摘要:
A hafnium-containing silazane polymer is obtained through a polymerization reaction of which the reactants are(A) a halide of an organic silicon compound;(B) a hafnium compound having a the formula:HfX.sub.4 [I]wherein X is chlorine or bromine, and(C) a disilazane having the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or different and are hydrogen, methyl ethyl, phenyl or vinyl.
摘要:
Hollow ceramic fibers are prepared by melt spinning an organic silazane polymer, infusibilizing the fiber to form an infusible layer on the surface, and pyrolyzing the fiber to obtain a ceramic fiber having an empty interior. The infusibilizing step includes two steps of treating the fiber with a gas containing the vapor of an infusibilizing silicon, boron, phosphorus or metal compound and further treating with a water vapor-containing gas or ammonia-containing gas. The surface infusible fibers are efficiently sintered into hollow ceramic fibers without fusion bond.
摘要:
A process for manufacturing an organic silazane polymer which comprises reacting an organic silicon compound of the following formula (I): ##STR1## in which R represents hydrogen, chlorine, bromine, methyl radical, ethyl radical, phenyl radical or vinyl radical, R.sub.1 represents hydrogen or methyl radical and X represents chlorine or bromine, or a mixture of organic silicon compounds of the formula (I) above and an organic silicon compound of the following formula (II): ##STR2## in which R.sub.2 and R.sub.3 represent hydrogen, chlorine, bromine, methyl radical, ethyl radical, phenyl radical or vinyl radical and X represents chlorine or bromine with a disilazane of the following formula (III): ##STR3## in which R.sub.4, R.sub.5, R.sub.6 represents hydrogen, methyl radical, ethyl radical, phenyl radical or vinyl radical in an anhydrous state at a temperature of from 25.degree. to 350.degree. C. while distilling off by-produced organic ingredients out of the system to obtain an organic silazane polymer. The organic silazane polymer is useful for preceramic materials.
摘要:
A hafnium-containing silazane polymer is obtained through a polymerization reaction of which the reactants are(A) a halide of an organic silicon compound;(B) a hafnium compound having a the formula:HfX.sub.4 [I] wherein X is chlorine or bromine, and(C) a disilazane having the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or different and are hydrogen, methyl ethyl, phenyl or vinyl.
摘要:
Polytitanocarbosilazane polymers useful as ceramic precursors are prepared by reacting organic silicon compounds of first and second types, a titanium compound, and a disilazane. Ceramic fibers are obtained by melt spinning the polymers followed by infusibilization and pyrolysis.
摘要:
A process for manufacturing an organic silazane polymer which comprises reacting ammonia with a mixture of methyldichlorosilane, methyltrichlorosilane and dimethyldichlorosilane to obtain an ammonolysis product. The ammonolysis product is polymerized in the presence of a basic catalyst capable of deprotonation to obtain an organic silazane polymer. The silazane polymer may be further melted, shaped and infusibilized. The thus infusibilized product is finally sintered to obtain a ceramic material.
摘要:
The invention provides a novel inorganic fiber composed of the elements of silicon, carbon, boron and nitrogen of which the Si/B molar ratio is 2:1 to 200:1. The inorganic fiber is obtained by a method comprising the steps of: (a) preparing an organoborosilicon polymer by heating a mixture of an organopolysilane and an organoborazine compound, e.g. B-trimethyl-N-triphenyl borazine, to effect thermal decomposition and polycondensation reaction; (b) spinning the polymer into a fibrous form; (c) infusibilizing the fiber of the polymer by thermally oxidizing in an oxidizing atmosphere or by irradiating with ionizing radiations; and (d) calcining the infusibilized fiber at 900.degree. to 1800.degree. C. The inventive inorganic fiber is more stable at high temperatures than conventional silicon carbide fibers.
摘要:
A process for manufacturing an organic silazane polymer which comprises reacting ammonia with a mixture of at least one compound selected from the group consisting of organic silicon compounds of the following formulae (I) and (II) ##STR1## and at least one compound selected from the group consisting of organic silicon compounds of the following formula (III) ##STR2## in which R represents hydrogen, chlorine, bromine, methyl radical, ethyl radical, phenyl radical or vinyl radical, R.sub.1 represents hydrogen or methyl radical, R.sub.2 represents hydrogen, methyl radical, ethyl radical, phenyl radical or vinyl radical and X represents chlorine or bromine; to obtain an ammonolysis product. The ammonolysis product is polymerized in the presence of a basic catalyst capable of deprotonation to obtain an organic silazane polymer. The silazane polymer may be further melted, shaped and infusibilized. The thus infusibilized product is finally sintered to obtain a ceramic material.
摘要:
A process for manufacturing an organic silazane polymer which comprises reacting ammonia with a mixture of methyldichlorosilane, methyltrichlorosilane and dimethyldichlorosilane to obtain an ammonolysis product. The ammonolysis product is polymerized in the presence of a basic catalyst capable of deprotonation to obtain an organic silazane polymer. The silazane polymer may be further melted, shaped and infusibilized. The thus infusibilized product is finally sintered to obtain a ceramic material.
摘要:
An organic silazane polymer is prepared by passing a silazane compound in por form through a hollow tube heated at 400.degree. to 700.degree. C. for activation and thermally polymerizing the silazane compound in a liquid phase. Inorganic fibers can be prepared from the organic silazane polymer by melt spinning, infusibilizing, and sintering. An apparatus for preparing an organic silazane polymer is also provided, comprising a heated reactor vessel for evaporating and thermally polymerizing a silazane compound, a heated hollow tube in flow communication with said reactor vessel for receiving the silazane compound vapor and heating it at 400.degree. to 700.degree. C. for activation, and a conduit, with a condenser for condensing the vapor, for feeding the condensed silazane compound back to the reactor.