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US 5,635,250 AGranted
Hydridosiloxanes as precursors to ceramic products
AssigneeSRI International
InventorsYigal D. Blum, Sylvia M. Johnson, Michael I. Gusman
Life of this patent
Estimating the term…
Abstract
A method is provided for preparing ceramic precursors from hydridosiloxane starting materials and then pyrolyzing these precursors to give rise to silicious ceramic materials. Si--H bonds present in the hydridosiloxane starting materials are catalytically activated, and the activated hydrogen atoms may then be replaced with nonhydrogen substituents. These preceramic materials are pyrolyzed in a selected atmosphere to give the desired ceramic product. Ceramic products which may be prepared by this technique include silica, silicon oxynitride, silicon carbide, metal silicates, and mullite.
Claims55
A method for preparing a ceramic material, comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a hydroxyl-containing compound of the formula R'--OH, wherein R' is (i) hydrogen, (ii) C.sub.1 -C.sub.10 alkyl or aryl of 1-2 rings, optionally substituted with hydroxyl, lower alkyl, halogeno, silyl, or amino groups, or combinations thereof, (iii) silyl optionally containing additional hydroxyl groups, or (iv) a metal optionally bound to one or more ligands and/or containing additional hydroxyl groups, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by oxygen-containing pendant groups OR' or oxygen-containing bridging moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing said cured preceramic mixture at a temperature of at least about 500.degree. C. to give said ceramic material.
5 more elements
A method for preparing a ceramic material, comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing carbon-containing moieties into said hydridosiloxane starting material by reaction with a compound containing an unsaturated carbon-carbon bond, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by pendant or bridging carbon-containing moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds and unsaturated carbon-carbon bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing said cured preceramic mixture at a temperature of at least about 500.degree. C. to give said ceramic material.
5 more elements
A method for preparing a ceramic material, comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing nitrogen-containing moieties into said starting material by reaction with a compound HNR".sub.2 wherein the R" are independently selected from hydrogen, lower alkyl, silyl, and aryl of 1-2 rings, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane polymer have been replaced with nitrogen-containing pendant or crosslinking groups;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing said cured preceramic mixture at a temperature of at least about 500.degree. C. to give said ceramic material.
5 more elements
A method for preparing a ceramic material, comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a compound selected from the group consisting of ML.sub.a and L.sub.a M-OH, wherein M is a metal atom, L is an organic or inorganic ligand associated therewith, and a represents the molar ratio L/M, to give a ceramic precursor in which said activated Si--H bonds have been replaced by Si--M bonds;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing said cured preceramic mixture at a temperature of at least about 500.degree. C. to give said ceramic material.
5 more elements
A method for preparing a ceramic material, comprising:
- (a) providing a starting material comprising a silicon-containing polymer having a plurality of Si--H groups;
- (b) curing said silicon-containing polymer with light, by dehydrocoupling or by reaction with a coupling agent, to provide a ceramic precursor;
- (c) admixing (i) a catalyst effective to activate Si--H bonds, and (ii) a metal powder, with either the silicon-containing polymer, the ceramic precursor, or both;
- and
- (d) pyrolyzing the mixture of step (c).
2 more elements
A ceramic coating prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a hydroxyl-containing compound of the formula R'--OH, wherein R' is (i) hydrogen, (ii) C.sub.1 -C.sub.10 alkyl or aryl of 1-2 rings, optionally substituted with hydroxyl, lower alkyl, halogeno, silyl, or amino groups, or combinations thereof, (iii) silyl optionally containing additional hydroxyl groups, or (iv) a metal optionally bound to one or more ligands and/or containing additional hydroxyl groups, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by oxygen-containing pendant groups OR' or oxygen-containing bridging moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing the preceramic mixture on a substrate, at a temperature of at least about 500.degree. C., to provide a ceramic coating thereon.
5 more elements
The ceramic coating composition of 21, wherein, in step (c), the ceramic precursor is admixed with a metal powder selected from the group consisting of aluminum, barium, boron, calcium, copper, hafnium, iron, magnesium, molybdenum, niobium, silicon, titanium, tungsten, yttrium and zirconium.
A ceramic coating prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing carbon-containing moieties into said hydridosiloxane starting material by reaction with a compound containing an unsaturated carbon-carbon bond, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by pendant or bridging carbon-containing moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds and unsaturated carbon-carbon bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing the preceramic mixture on a substrate, at a temperature of at least about 500.degree. C., to provide a ceramic coating thereon.
5 more elements
The ceramic coating composition of 26, wherein, in step (c), the ceramic precursor is admixed with a metal powder selected from the group consisting of aluminum, barium, boron, calcium, copper, hafnium, iron, magnesium, molybdenum, niobium, silicon, titanium, tungsten, yttrium and zirconium.
A ceramic coating prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing nitrogen-containing moieties into said starting material by reaction with a compound HNR".sub.2 wherein the R" are independently selected from hydrogen, lower alkyl, silyl, and aryl of 1-2 rings, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane polymer have been replaced with nitrogen-containing pendant or crosslinking groups;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing the preceramic mixture on a substrate, at a temperature of at least about 500.degree. C., to provide a ceramic coating thereon.
5 more elements
A ceramic coating prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a compound selected from the group consisting of ML.sub.a and L.sub.a M-OH, wherein M is a metal atom, L is an organic or inorganic ligand associated therewith, and a represents the molar ratio L/M, to give a ceramic precursor in which Said activated Si--H bonds have been replaced by Si--M bonds;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- and
- (e) pyrolyzing the preceramic mixture on a substrate, at a temperature of at least about 500.degree. C., to provide a ceramic coating thereon.
5 more elements
A ceramic coating composition prepared by the process comprising:
- (a) providing a starting material comprising a silicon-containing polymer having a plurality of Si--H groups;
- (b) curing said silicon-containing polymer with light, by dehydrocoupling or by reaction with a coupling agent, to provide a ceramic precursor;
- (c) admixing (i) a catalyst effective to activate Si--H bonds, and (ii) a metal powder, with either the silicon-containing polymer, the ceramic precursor, or both, to provide a preceramic mixture;
- (d) coating a substrate with the preceramic mixture, whereby a preceramic coating is provided;
- and
- (e) pyrolyzing the preceramic ceramic coating on the substrate, to provide a ceramic coating thereon.
3 more elements
A fiber-reinforced ceramic matrix composite prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a hydroxyl-containing compound of the formula R'--OH, wherein R' is (i) hydrogen, (ii) C.sub.1 -C.sub.10 alkyl or aryl of 1-2 rings, optionally substituted with hydroxyl, lower alkyl, halogeno, silyl, or amino groups, or combinations thereof, (iii) silyl optionally containing additional hydroxyl groups, or (iv) a metal optionally bound to one or more ligands and/or containing additional hydroxyl groups, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by oxygen-containing pendant groups OR' or oxygen-containing bridging moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- (e) incorporating ceramic fibers into the preceramic mixture, either prior to or during step (d), to provide a fiber-containing preceramic mixture;
- and
- (f) pyrolyzing the fiber-containing preceramic mixture, at a temperature of at least about 500.degree. C., to provide a fiber-reinforced ceramic matrix composite.
6 more elements
A fiber-reinforced ceramic matrix composite prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing carbon-containing moieties into said hydridosiloxane starting material by reaction with a compound containing an unsaturated carbon-carbon bond, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane starting material have been replaced by pendant or bridging carbon-containing moieties;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds and unsaturated carbon-carbon bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- (e) incorporating ceramic fibers into the preceramic mixture, either prior to or during step (d), to provide a fiber-containing preceramic mixture;
- and
- (f) pyrolyzing the fiber-containing preceramic mixture, at a temperature of at least about 500.degree. C., to provide a fiber-reinforced ceramic matrix composite.
6 more elements
A ceramic matrix composite prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) introducing nitrogen-containing moieties into said starting material by reaction with a compound HNR".sub.2 wherein the R" are independently selected from hydrogen, lower alkyl, silyl, and aryl of 1-2 rings, to give a ceramic precursor in which hydrogen atoms in the hydridosiloxane polymer have been replaced with nitrogen-containing pendant or crosslinking groups;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- (e) incorporating ceramic fibers into the preceramic mixture, either prior to or during step (d), to provide a fiber-containing preceramic mixture;
- and
- (f) pyrolyzing the fiber-containing preceramic mixture, at a temperature of at least about 500.degree. C., to provide a fiber-reinforced ceramic matrix composite.
6 more elements
A fiber-reinforced ceramic matrix composite prepared by the process comprising:
- (a) providing a hydridosiloxane starting material containing a plurality of Si--H bonds, and wherein at least about 20% of the silicon atoms present in the starting material have a hydrogen atom bound thereto;
- (b) reacting said hydridosiloxane starting material with a compound selected from the group consisting of ML.sub.a and L.sub.a M-OH, wherein M is a metal atom, L is an organic or inorganic ligand associated therewith, and a represents the molar ratio L/M, to give a ceramic precursor in which said activated Si--H bonds have been replaced by Si--M bonds;
- (c) adding a metal powder, a ceramic powder, or both, either prior to, during, or after step (b),
- wherein a catalyst effective to activate Si--H bonds is added in step (b), step (c) or both,
- such that a preceramic mixture is provided;
- (d) curing the preceramic mixture at a temperature between approximately 20.degree. C. and 250.degree. C., to provide a cured preceramic mixture;
- (e) incorporating ceramic fibers into the preceramic mixture, either prior to or during step (d), to provide a fiber-containing preceramic mixture;
- and
- (f) pyrolyzing the fiber-containing preceramic mixture, at a temperature of at least about 500.degree. C., to provide a fiber-reinforced ceramic matrix composite.
6 more elements
A fiber-reinforced ceramic matrix composite prepared by the process comprising:
- (a) providing a starting material comprising a silicon-containing polymer having a plurality of Si--H groups;
- (b) curing said silicon-containing polymer with light, by dehydrocoupling or by reaction with a coupling agent, to provide a ceramic precursor;
- (c) admixing (i) a catalyst effective to activate Si--H bonds, and (ii) a metal powder, with either the silicon-containing polymer, the ceramic precursor, or both, to provide a preceramic mixture;
- (d) incorporating ceramic fibers into the preceramic mixture to provide a fiber-containing preceramic mixture;
- and
- (e) pyrolyzing the fiber-containing preceramic mixture, at a temperature of at least about 500.degree. C., to provide a fiber-reinforced ceramic matrix composite.
3 more elements
Dependencies are inferred from the claim text.