US4983555A
Expired / Lapsed
US
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Application of transparent polycrystalline body with high ultraviolet transmittance
Assignee: Coors Ceramics Co
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Filing: 1988-04-22
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Granted: 1991-01-08
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Expires: 2008-04-22
Abstract
Abstract A transparent polycrystalline body having high ultraviolet transmissivity is provided. The body is preferably a sintered magnesia-alumina spinel body having a transmittance of at least 85 percent in the wavelength range from 0.4 microns to 0.8 microns and a transmittance at some wavelength in the wavelength range between about 0.2 and about 0.4 microns of at least about 86 percent and a porosity of less than about 0.001 percent. The sintered body is produced by a two-step method comprising forming a closed porosity body from a spinel powder and subjecting the closed porosity body to a hot isostatic pressure treatment. The resulting body has high transmissivity of electromagnetic radiation in the range between about 0.2 microns and about 6 microns, is resistant to abrasion or erosion, does not substantially deteriorate after exposure to ultraviolet light, and has high strength. A number of applications of the magnesia-alumina spinel body are disclosed for which the material is advantageous.
Inventors
- 👤 Donald W. Roy
- 👤 James L. Hastert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:14
CPC Classifications
H; H01; H01Q; H01Q1/00; H01Q1/42; C; C04; C04B; C04B35/00; C04B35/01; C04B35/44; C04B35/443
Claims Analysis
Total Claims: 108
Claim 1
Independent Claim
79 words
A sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said body having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 2
Dependent Claim
79 words
A sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said body having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 3
Dependent Claim
22 words
A sintered polycrystalline body, as claimed in claim 1, wherein: said body has a flexural strength of at least about 15,000 psi.
Claim 4
Dependent Claim
26 words
A sintered polycrystalline body, as claimed in claim 1, wherein: said sintered body has a knoop hardness of at least about 1350 kg mm -2 .
Claim 5
Dependent Claim
21 words
A sintered polycrystalline body, as claimed in claim 1, wherein: said body has a grain size less than about 150 microns.
Claim 6
Dependent Claim
22 words
A sintered polycrystalline body, as claimed in claim 1, wherein: said body has a tensile strength of at least about 12,000 psi.
Claim 7
Dependent Claim
41 words
A sintered polycrystalline body, as claimed in claim 1, wherein: said body has a strength such that a 3 inch diameter disk having a thickness of about 0.6 inches bursts when subjected to a pressure of more than about 25 psi.
Claim 8
Dependent Claim
15 words
A sintered polycrystalline body as claimed in claim 1 comprising at least 99.9% magnesia-alumina spinel.
Claim 9
Dependent Claim
43 words
A sintered polycrystalline body as claimed in claim 1 wherein said step of heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20.000 psi to reduce residual porosity is accomplished by hot isostatic pressing.
Claim 10
Dependent Claim
17 words
A sintered polycrystalline body as claimed in claim 1 wherein said body has less than 0.01% porosity.
Claim 11
Dependent Claim
82 words
A window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 12
Dependent Claim
82 words
A window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 13
Dependent Claim
80 words
A pressure vessel sight glass consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said sight glass having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 14
Dependent Claim
80 words
A pressure vessel sight glass consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said sight glass having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 15
Dependent Claim
80 words
A furnace sight glass consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said sight glass having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 16
Dependent Claim
80 words
A furnace sight glass consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said sight glass having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 17
Dependent Claim
80 words
A windshield for a vehicle consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said windshield having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 18
Dependent Claim
80 words
A windshield for a vehicle consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said windshield having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 19
Dependent Claim
92 words
A UPC bar code scanning device window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said UPC bar code scanning device window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 20
Dependent Claim
92 words
A UPC bar code scanning device window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said UPC bar code scanning device window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 21
Dependent Claim
82 words
A waveguide comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said waveguide having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 22
Dependent Claim
82 words
A waveguide comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said waveguide having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 23
Dependent Claim
98 words
A feed-through in an optical downhole well logging sensing system comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said feed-through in an optical downhole well logging sensing system having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 24
Dependent Claim
98 words
A feed-through in an optical downhole well logging sensing system comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said feed-through in an optical downhole well logging sensing system having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 25
Dependent Claim
86 words
An optical fiber connector comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber connector having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 26
Dependent Claim
86 words
An optical fiber connector comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber connector having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 27
Dependent Claim
90 words
A pump piston for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pump piston for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 28
Dependent Claim
90 words
A pump piston for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pump piston for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 29
Dependent Claim
90 words
A pump cylinder for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pump cylinder for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 30
Dependent Claim
90 words
A pump cylinder for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pump cylinder for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 31
Dependent Claim
88 words
A column for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said column for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 32
Dependent Claim
88 words
A column for chromatography applications comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said column for chromatography applications having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 33
Dependent Claim
86 words
A thermoset mold window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said thermoset mold window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 34
Dependent Claim
86 words
A thermoset mold window comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said thermoset mold window having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 35
Dependent Claim
86 words
A water-jet cutting flow-shaper comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said water-jet cutting flow-shaper having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 36
Dependent Claim
86 words
A water-jet cutting flow-shaper comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said water-jet cutting flow-shaper having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 37
Dependent Claim
88 words
A nozzle for process fluids comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said nozzle for process fluids having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 38
Dependent Claim
88 words
A nozzle for process fluids comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said nozzle for process fluids having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 39
Dependent Claim
84 words
A valve flap comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said valve flap having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 40
Dependent Claim
84 words
A valve flap comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said valve flap having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 41
Dependent Claim
84 words
A valve seat comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said valve seat having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 42
Dependent Claim
84 words
A valve seat comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said valve seat having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 43
Dependent Claim
90 words
A component in integrated-circuit imaging equipment comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said component in integrated-circuit imaging equipment having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 44
Dependent Claim
90 words
A component in integrated-circuit imaging equipment comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said component in integrated-circuit imaging equipment having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 45
Dependent Claim
86 words
A high-pressure arc-lamp enclosure comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said high-pressure arc-lamp enclosure having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 46
Dependent Claim
86 words
A high-pressure arc-lamp enclosure comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said high-pressure arc-lamp enclosure having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 47
Dependent Claim
88 words
A high-pressure arc lamp lens comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said high-pressure arc lamp lens having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 48
Dependent Claim
88 words
A high-pressure arc lamp lens comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said high-pressure arc lamp lens having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 49
Dependent Claim
94 words
A port for receiving and transmitting radiation signals comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said port for receiving and transmitting radiation signals having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 50
Dependent Claim
94 words
A port for receiving and transmitting radiation signals comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said port for receiving and transmitting radiation signals having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 51
Dependent Claim
92 words
A port for missile guidance and detection comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said port for missile guidance and detection having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 52
Dependent Claim
92 words
A port for missile guidance and detection comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said port for missile guidance and detection having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 53
Dependent Claim
84 words
A ball bearing comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said ball bearing having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 54
Dependent Claim
84 words
A ball bearing comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said ball bearing having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 55
Dependent Claim
91 words
Components in a high speed printer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said components in a high speed printer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 56
Dependent Claim
91 words
Components in a high speed printer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said components in a high speed printer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 57
Dependent Claim
88 words
A liquid ink plotting pen comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said liquid ink plotting pen having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 58
Dependent Claim
88 words
A liquid ink plotting pen comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said liquid ink plotting pen having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 59
Dependent Claim
84 words
An optical lens comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical lens having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 60
Dependent Claim
84 words
An optical lens comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical lens having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 61
Dependent Claim
87 words
Components for optical computers comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said components for optical computers having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 62
Dependent Claim
87 words
Components for optical computers comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said components for optical computers having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 63
Dependent Claim
84 words
An optical fiber comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising; providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 64
Dependent Claim
84 words
An optical fiber comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising; providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 65
Dependent Claim
82 words
A thermometer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said thermometer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 66
Dependent Claim
82 words
A thermometer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said thermometer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 67
Dependent Claim
86 words
An optical fiber sensor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber sensor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 68
Dependent Claim
86 words
An optical fiber sensor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said optical fiber sensor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 69
Dependent Claim
84 words
A flow meter comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said flow meter having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 70
Dependent Claim
84 words
A flow meter comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said flow meter having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 71
Dependent Claim
84 words
A capillary tube comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said capillary tube having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 72
Dependent Claim
84 words
A capillary tube comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said capillary tube having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 73
Dependent Claim
84 words
A pressure transducer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pressure transducer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 74
Dependent Claim
84 words
A pressure transducer comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said pressure transducer having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 75
Dependent Claim
88 words
A wafer for electronic application comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said wafer for electronic application having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 76
Dependent Claim
88 words
A wafer for electronic application comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said wafer for electronic application having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 77
Dependent Claim
86 words
A cryogenic temperature sensor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said cryogenic temperature sensor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 78
Dependent Claim
86 words
A cryogenic temperature sensor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said cryogenic temperature sensor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 79
Dependent Claim
84 words
A watch crystal comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said watch crystal having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 80
Dependent Claim
84 words
A watch crystal comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said watch crystal having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 81
Dependent Claim
83 words
Safety goggles comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said safety goggles having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 82
Dependent Claim
83 words
Safety goggles comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said safety goggles having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 83
Dependent Claim
81 words
Cookware comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said cookware having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 84
Dependent Claim
81 words
Cookware comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said cookware having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 85
Dependent Claim
84 words
A rotary encoder comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said rotary encoder having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 86
Dependent Claim
84 words
A rotary encoder comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said rotary encoder having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 87
Dependent Claim
88 words
A fiber optic beam splitter comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said fiber optic beam splitter having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 88
Dependent Claim
88 words
A fiber optic beam splitter comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said fiber optic beam splitter having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 89
Dependent Claim
90 words
A covering for a submarine port comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said covering for a submarine port having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 90
Dependent Claim
90 words
A covering for a submarine port comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said covering for a submarine port having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 91
Dependent Claim
90 words
A covering for a tank port comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said covering for a tank port having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 92
Dependent Claim
90 words
A covering for a tank port comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said covering for a tank port having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 93
Dependent Claim
84 words
A carrier disk comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said carrier disk having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 94
Dependent Claim
84 words
A carrier disk comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said carrier disk having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 95
Dependent Claim
88 words
A radiation hardened RAM substrate comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said radiation hardened RAM substrate having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 96
Dependent Claim
88 words
A radiation hardened RAM substrate comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said radiation hardened RAM substrate having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 97
Dependent Claim
84 words
A trimmer capacitor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said trimmer capacitor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 98
Dependent Claim
84 words
A trimmer capacitor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said trimmer capacitor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 99
Dependent Claim
82 words
A prism comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said prism having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 100
Dependent Claim
82 words
A prism comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said prism having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 101
Dependent Claim
81 words
Armor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said armor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 102
Dependent Claim
81 words
Armor comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said armor having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 103
Dependent Claim
84 words
A fuse cover comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said fuse cover having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 104
Dependent Claim
84 words
A fuse cover comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said fuse cover having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 105
Dependent Claim
84 words
A holographic grating comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said holographic grating having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 106
Dependent Claim
84 words
A holographic grating comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said holographic grating having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 107
Dependent Claim
84 words
A diffraction grating comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said diffraction grating having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
Claim 108
Dependent Claim
84 words
A diffraction grating comprising a sintered polycrystalline body consisting essentially of magnesia-alumina spinel produced by a process comprising: providing a powder comprising magnesia-alumina spinel; producing a closed porosity body from said powder; and heating said closed porosity body to at least about 1400° C. at elevated pressure of at least about 20,000 psi to reduce residual porosity; said diffraction grating having a transmittance per 1.88 millimeter thickness in all wavelengths from about 0.3 to about 0.8 microns of not less than about 85 percent.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |