EP0228022A2
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Process for preparing a silicon nitride powder mixture
Assignee: Mitsubishi Chemical Corp
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Filing: 1986-12-16
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Granted: —
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Expires: 2006-12-16
Abstract
Abstract A process for preparing a silicon nitride powder mixture with at least one metal oxide, which comprises mixing silicon nitride powder with a solution containing at least one nitrate of metal selected from the group consisting of metals of Groups IIA, IIB, IIIA, IIIB and IVA of the Periodic Table, then evaporating the solvent of said solution to dry the mixture, and baking the dried mixture to convert the metal nitrate to the corresponding metal oxide.
Inventors
- 👤 Tsugio Kaneko
- 👤 Yoshinobu Nishiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 00:39
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/515; C04B35/58; C04B35/584
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
76 words
A process for preparing a silicon nitride powder mixture with at least one metal oxide, which comprises mixing silicon nitride powder with a solution containing at least one nitrate of metal selected from the group consisting of metals of Groups IIA, IIB, IIIA, IIIB and IVA of the Periodic Table, then evaporating the solvent of said solution to dry the mixture, and baking the dried mixture to convert the metal nitrate to the corresponding metal oxide.
Claim 2
Dependent Claim
76 words
A process for preparing a silicon nitride powder mixture with at least one metal oxide, which comprises mixing silicon nitride powder with a solution containing at least one nitrate of metal selected from the group consisting of metals of Groups IIA, IIB, IIIA, IIIB and IVA of the Periodic Table, then evaporating the solvent of said solution to dry the mixture, and baking the dried mixture to convert the metal nitrate to the corresponding metal oxide.
Claim 3
Dependent Claim
31 words
The process according to Claim l, wherein the metal is magnesium, calcium, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, aluminum or zirconium.
Claim 4
Dependent Claim
36 words
The process according to Claim l, wherein the solvent of the solution containing the nitrate is at least one member selected from the group consisting of water and alcohols having from l to 4 carbon atoms.
Claim 5
Dependent Claim
34 words
The process according to Claim l, wherein the metal oxide is incorporated in an amount of from l to 30% by weight as calculated as the oxide, relative to the silicon nitride powder mixture.
Claim 6
Dependent Claim
43 words
The process according to Claim l, wherein the slurry concentration of the mixture obtained by mixing the silicon nitride powder with the nitrate-containing solution, is from l to 60% by weight, and the baking is conducted at a temperature of at least 450°C.
Claim 7
Dependent Claim
82 words
A process for preparing a silicon nitride powder mixture with at least one metal oxide, which comprises mixing silicon nitride powder with a solution containing at least one nitrate of metal selected from the group consisting of metals of Groups IIA, IIB, IIIA, IIIB and IVA of the Periodic Table, then evaporating the solvent of said solution to dry the mixture, baking the dried mixture to convert the metal nitrate to the corresponding metal oxide, and pulverizing the powder mixture thus obtained.
Claim 8
Dependent Claim
82 words
A process for preparing a silicon nitride powder mixture with at least one metal oxide, which comprises mixing silicon nitride powder with a solution containing at least one nitrate of metal selected from the group consisting of metals of Groups IIA, IIB, IIIA, IIIB and IVA of the Periodic Table, then evaporating the solvent of said solution to dry the mixture, baking the dried mixture to convert the metal nitrate to the corresponding metal oxide, and pulverizing the powder mixture thus obtained.
Claim 9
Dependent Claim
31 words
The process according to Claim 6, wherein the metal is magnesium, calcium, scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, aluminum or zirconium.
Claim 10
Dependent Claim
36 words
The process according to Claim 6, wherein the solvent of the solution containing the nitrate is at least one member selected from the group consisting of water and alcohols having from l to 4 carbon atoms.
Claim 11
Dependent Claim
79 words
The process according to Claim 6, wherein the pulverization is conducted until the pore size distribution of a compact obtained by monoaxially pressing the pulverized silicon nitride powder mixture under a pressure of l ton/cm², has a mode pore diameter ratio of at most l.5 and a relative half value width ratio of at most l.5, as compared with the pore size distribution of a compact obtained by pressing the starting material silicon nitride powder under the same conditions.
Claim 12
Dependent Claim
19 words
l0. The process according to Claim 6, wherein the pulverization is conducted in the presence of a non-aqueous solvent.
Claim 13
Dependent Claim
34 words
The process according to Claim 6, wherein the metal oxide is incorporated in an amount of from l to 30% by weight as calculated as the oxide relative to the silicon nitride powder mixture.
Claim 14
Dependent Claim
43 words
The process according to Claim 6, wherein the slurry concentration of the mixture obtained by mixing the silicon nitride powder with a nitrate-containing solution, is from l to 60% by weight, and the baking is conducted at a temperature of at least 450°C.
References Cited (Backward Citations)
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