US4613490A — Process for preparing silicon nitride, silicon ca…

Claim 1

Independent Claim 170 words

A process for preparing fine silicon nitride powders, which comprise carrying out a vapor phase reaction of a silicon compound comprising an aminosilane compound represented by the following general formula: RnSi(NR'R").sub.m where R, R' and R" represent hydrogen atoms, alkyl groups, allyl groups, and phenyl groups, excluding R, R' and R" being hydrogen atoms at the same time, n=0 to 3, and m=4-n, or a cyanosilane compound represented by the following general formula: RnSi(CN).sub.m where R represents a hydrogen atom, an alkyl group, an allyl group, and a phenyl group, n=0 to 3 and m=4-n, or a silazane compound represented by the general formula: [R R' R" Si].sub.2 NR'", or --RR'Si--NR"].sub.n where R, R', R", and R'" represent hydrogen atoms, alkyl groups, allyl groups, methylamino groups, and phenyl groups, excluding R, R', R" and R"' being hydrogen atoms at the same time, and n is 3 or 4, in the presence of ammonia, and heat treating the resulting fine silicon nitride powders in an inert gas or non-oxidizing gas atmosphere.

Claim 2

Dependent Claim 170 words

A process for preparing fine silicon nitride powders, which comprise carrying out a vapor phase reaction of a silicon compound comprising an aminosilane compound represented by the following general formula: RnSi(NR'R").sub.m where R, R' and R" represent hydrogen atoms, alkyl groups, allyl groups, and phenyl groups, excluding R, R' and R" being hydrogen atoms at the same time, n=0 to 3, and m=4-n, or a cyanosilane compound represented by the following general formula: RnSi(CN).sub.m where R represents a hydrogen atom, an alkyl group, an allyl group, and a phenyl group, n=0 to 3 and m=4-n, or a silazane compound represented by the general formula: [R R' R" Si].sub.2 NR'", or --RR'Si--NR"].sub.n where R, R', R", and R'" represent hydrogen atoms, alkyl groups, allyl groups, methylamino groups, and phenyl groups, excluding R, R', R" and R"' being hydrogen atoms at the same time, and n is 3 or 4, in the presence of ammonia, and heat treating the resulting fine silicon nitride powders in an inert gas or non-oxidizing gas atmosphere.

Claim 3

Dependent Claim 19 words

A process according to claim 1 wherein a molar ratio of the ammonia to said silicon compound is 1-50:1.

Claim 4

Dependent Claim 76 words

A process for preparing fine silicon nitride powders which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere including nitrogen and ammonia of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R' represent alkyl groups, allyl groups and phenyl groups, and n=0, 1, 2, or 3, and heat treating the resulting fine powders containing 28.6 to 70%, by weight, of carbon based on the total weight of powders.

Claim 5

Dependent Claim 76 words

A process for preparing fine silicon nitride powders which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere including nitrogen and ammonia of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R' represent alkyl groups, allyl groups and phenyl groups, and n=0, 1, 2, or 3, and heat treating the resulting fine powders containing 28.6 to 70%, by weight, of carbon based on the total weight of powders.

Claim 6

Dependent Claim 21 words

A process according to claim 3, wherein the heat treatment is carried out at a temperature of 1,350° to 1,550° C.

Claim 7

Dependent Claim 58 words

A process for preparing fine silicon nitride powders which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas including ammonia in a molar ratio of the inert carrier gas to silicon of 3-5:1, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 8

Dependent Claim 58 words

A process for preparing fine silicon nitride powders which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas including ammonia in a molar ratio of the inert carrier gas to silicon of 3-5:1, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 9

Dependent Claim 162 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction of a silicon compound comprising an aminosilane compound represented by the following general formula: RnSi(NR'R").sub.m where R, R' and R' represent hydrogen atoms, alkyl groups, allyl groups, and phenyl groups excluding R, R' and R" being hydrogen atoms at the same time, and n=0 to 3 and m=4-n, or a cyanosilane compound represented by the following general formula: RnSi(CN).sub.m where R represents a hydrogen atom, an alkyl group, an allyl group and a phenyl group, n=0 to 3 and m=4-n, or a silazane compound represented by the following general formula: [R R' R" Si].sub.2 NR", or --RR'Si-NR"].sub.n where R, R', R" and R"' represent hydrogen atoms, alkyl groups, allyl groups, methylamino groups and phenyl groups, excluding R, R', R" and R"' being hydrogen atoms at the same time, and n is 3 or 4, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 10

Dependent Claim 162 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction of a silicon compound comprising an aminosilane compound represented by the following general formula: RnSi(NR'R").sub.m where R, R' and R' represent hydrogen atoms, alkyl groups, allyl groups, and phenyl groups excluding R, R' and R" being hydrogen atoms at the same time, and n=0 to 3 and m=4-n, or a cyanosilane compound represented by the following general formula: RnSi(CN).sub.m where R represents a hydrogen atom, an alkyl group, an allyl group and a phenyl group, n=0 to 3 and m=4-n, or a silazane compound represented by the following general formula: [R R' R" Si].sub.2 NR", or --RR'Si-NR"].sub.n where R, R', R" and R"' represent hydrogen atoms, alkyl groups, allyl groups, methylamino groups and phenyl groups, excluding R, R', R" and R"' being hydrogen atoms at the same time, and n is 3 or 4, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 11

Dependent Claim 43 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 12

Dependent Claim 43 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 13

Dependent Claim 73 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R'represent alkyl groups, allyl groups and phenyl groups, and n is 0, 1, 2, or 3, and heat treating the resulting fine powders containing 37.5 to 70%, by weight, of carbon based on the total weight of powders.

Claim 14

Dependent Claim 73 words

A process for preparing fine silicon carbide powders which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R'represent alkyl groups, allyl groups and phenyl groups, and n is 0, 1, 2, or 3, and heat treating the resulting fine powders containing 37.5 to 70%, by weight, of carbon based on the total weight of powders.

Claim 15

Dependent Claim 85 words

A process for preparing a fine powdery mixture of silicon nitride and silicon carbide which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere including nitrogen and ammonia of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R' represent alkyl groups, allyl groups and phenyl groups, and n is 0, 1, 2, or 3, and heat treating the resulting fine powders containing 37.5 to 70%, by weight, of carbon based on the total weight of the powders.

Claim 16

Dependent Claim 85 words

A process for preparing a fine powdery mixture of silicon nitride and silicon carbide which comprises carrying out a vapor phase reaction in a non-oxidizing gas atmosphere including nitrogen and ammonia of an alkoxysilane compound represented by the following general formula: RnSi(OR').sub.4-n where R and R' represent alkyl groups, allyl groups and phenyl groups, and n is 0, 1, 2, or 3, and heat treating the resulting fine powders containing 37.5 to 70%, by weight, of carbon based on the total weight of the powders.

Claim 17

Dependent Claim 21 words

A process according to claim 9, wherein the heat treatment is carried out at a temperature of 1,450° to 1,550° C.

Claim 18

Dependent Claim 67 words

A process for preparing a fine powdery mixture of silicon nitride and silicon carbide, which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas including ammonia, where a molar ratio of ammonia as a carrier gas to silicon is 0.1 to 3:1, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 19

Dependent Claim 67 words

A process for preparing a fine powdery mixture of silicon nitride and silicon carbide, which comprises carrying out a vapor phase reaction of a siloxane compound free from a halogen substituent together with an inert carrier gas including ammonia, where a molar ratio of ammonia as a carrier gas to silicon is 0.1 to 3:1, and heat treating the resulting fine powders in a non-oxidizing gas atmosphere.

Claim 20

Dependent Claim 21 words

A process according to claim 11 wherein the heat treatment is carried out at a temperature of 1,350° to 1,850° C.

Claim 21

Dependent Claim 14 words

A process according to claim 1 wherein said silicon compound is said aminosilane compound.

Claim 22

Dependent Claim 14 words

A process according to claim 1 wherein said silicon compound is said cyanosilane compound.

Claim 23

Dependent Claim 14 words

A process according to claim 1 wherein said silicon compound is said silazane compound.

Claim 24

Dependent Claim 14 words

A process according to claim 6 wherein said silicon compound is said aminosilane compound.

Claim 25

Dependent Claim 14 words

A process according to claim 6 wherein said silicon compound is said cyanosilane compound.

Claim 26

Dependent Claim 14 words

A process according to claim 6 wherein said silicon compound is said silazane compound.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-09-22	1990-03-24	1990-09-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-09-22	1994-03-24	1994-09-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-09-22	1998-03-24	1998-09-23	$7700.00	Window Closed / Lapsed

Process for preparing silicon nitride, silicon carbide or fine powdery mixture thereof

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