US5149338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Superpolishing agent, process for polishing hard ceramic materials, and polished hard ceramics
Assignee: Planar Technologies Inc
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Filing: 1991-07-22
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Granted: 1992-09-22
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Expires: 2011-07-22
Abstract
Abstract A process for superpolishing hard ceramic substrates, and super polished substrates having surface finishes below about 20 angstroms RMS. The process comprises applying a pitch to a lap tool and forming channels in the pitch. The pitch is wetted with a polishing compound comprising colloidal alumina and powder of a substance harder than that being polished. The substrate is brought into contact with the wetted pitch, and a relative motion is applied thereto to polish the substrate.
Inventors
- 👤 Kenneth W. Fulton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 04:18
CPC Classifications
B; B24; B24B; B24B37/00; B24B37/04; C; C09; C09K; C09K3/00; C09K3/14; C09K3/1454; C09K3/1463
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
79 words
A process for polishing hard ceramic materials to a surface roughness below about 20 angstroms RMS, comprising: a. forming a layer of petroleum pitch on a polishing tool; b. forming channels in said pitch; c. wetting said pitch with a polishing compound comprising colloidal alumina and a powder of a substance that is harder than the substrate to be polished; and d. contacting said substrate to be polished with said wetted pitch and imparting relative motion to said substrate.
Claim 2
Dependent Claim
79 words
A process for polishing hard ceramic materials to a surface roughness below about 20 angstroms RMS, comprising: a. forming a layer of petroleum pitch on a polishing tool; b. forming channels in said pitch; c. wetting said pitch with a polishing compound comprising colloidal alumina and a powder of a substance that is harder than the substrate to be polished; and d. contacting said substrate to be polished with said wetted pitch and imparting relative motion to said substrate.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein said powder is selected from the group consisting of diamond, boron carbide and imitation diamond powder.
Claim 4
Dependent Claim
22 words
The process of claim 2 wherein the powder is diamond powder having particles of diamond that average about 3 microns in diameter.
Claim 5
Dependent Claim
11 words
The process of claim 1 wherein said substrate comprises silicon carbide.
Claim 6
Dependent Claim
13 words
The process of claim 1 wherein said substrate comprises CVD coated silicon carbide.
Claim 7
Dependent Claim
26 words
The process of claim 1 wherein said relative motion is imparted by spinning said polishing tool and by moving said substrate horizontally across the spinning tool.
Claim 8
Dependent Claim
20 words
The process of claim 1 wherein said substrate is polished to a surface roughness less than about 10 angstroms RMS.
Claim 9
Dependent Claim
19 words
The process of claim 1 wherein said substrate is polished to a surface roughness of about 2 angstroms RMS.
Claim 10
Dependent Claim
19 words
The process of claim 1 wherein said substrate is polished to a surface roughness of about 0.5 angstroms RMS.
Claim 11
Dependent Claim
55 words
The process of claim 1 wherein said layer of pitch is formed on said polishing tool by forming a dam on said polishing tool; heating said pitch to a liquid state; and applying said pitch to said tool while said pitch is in the liquid state, said dam confining the liquid pitch to said tool.
Claim 12
Dependent Claim
14 words
The process of claim 1 wherein said polishing compound is continuously agitated during polishing.
Claim 13
Dependent Claim
29 words
The hard ceramic substrate of claim 1 wherein said substrate comprises a material selected from the group consisting of silicon carbide, CVD-coated silicon carbide, and pure CVD silicon carbide.
References Cited (Backward Citations)
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Cited
US4270932A
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US4242842A
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US4935039A
Cited
US5000761A
Cited
US4952240A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |