Abstract:
A block copolymer is prepared by reacting an aluminum-nitrogen polymer and a silazane polymer at a temperature not greater than 400°C. Block copolymers containing alkenyl or alkynyl groups can be crosslinked by supplying energy to generate free radicals. An AlN/SiC-containing ceramic is formed by pyrolyzing the crosslinked block copolymer in a nonoxidizing atmosphere.
Abstract:
A sintered, Si₃N₄-containing ceramic article is prepared by a reaction injection molding process comprising (1) injecting into a heated mold a fluid, nondilatant mixture of (a) at least 40% by volume of a powder mixture of (i) Si₃N₄, (ii) a silicate glass-forming sintering aid and (iii) a high metal content silicide, and (b) a curable Si₃N₄ precursor binder, to cure the binder and produce a hardened molded article, (2) heating the hardened molded article under a suitable atmosphere to convert the cured binder to a Si₃N₄-containing ceramic, and (3) sintering the molded article under a vacuum to crystallize the silicate glass phase by deoxygenation.
Abstract translation:通过反应注射成型方法制备烧结的含Si 3 N 4的陶瓷制品,其包括(1)向加热的模具中注入(a)至少40体积%的(i)Si 3 N 4的粉末混合物的流体,非稀释剂混合物, (ii)硅酸盐玻璃形成烧结助剂和(iii)高金属含量硅化物,和(b)可固化Si 3 N 4前体粘合剂,以固化粘合剂并制备硬化的模制品,(2)将硬化的模制品加热到 将固化的粘合剂转化为含Si 3 N 4的陶瓷的合适气氛,和(3)在真空下烧结成型制品以通过脱氧使硅酸盐玻璃相结晶。
Abstract:
A silicon nitride ceramic having crystalline grain boundary phases is prepared by heating a composition comprising silicon nitride, a silicate glass-forming sintering aid and a high metal content transition metal silicide, to a temperature of 1300° to 1800°C under vacuum until a glass forms, oxygen is removed from the glass as SiO gas, and the glass crystallizes. Alternatively, the grain boundaries of a sintered composition comprising silicon nitride, a silicate glass and a high metal content transition metal silicide can be crystallized by heating to at least 1300°C under a vacuum.
Abstract:
Nouveau procédé de formation de corps macrocomposites par infiltration d'une masse perméable de matières de remplissage ou d'une préforme afin de former un corps composite matriciel en métal et, à l'aide d'un moyen approprié, par liaison dudit corps composite matriciel en métal formé à un autre corps. Dans un mode de réalisation préféré, notamment, une infiltration spontanée a lieu à l'aide d'un activateur d'infiltration et/ou d'un précurseur d'activateur d'infiltration et/ou d'une atmosphère d'infiltration lesquels sont en communication avec une matière de remplissage ou une préforme, au moins à un momnet donné pendant le processus, permettant ainsi à du métal matriciel fondu de s'infiltrer spontanément dns la matière de remplissage ou dans la préforme. Ladite infiltration spontanée a lieu sans application de pression ou de vide.
Abstract:
Disclosed is a wear resistant sintered ceramic product comprising (a) 40-98 weight percent silicon nitride having a high alpha-phase content, (b) 2-60 weight percent of a high metal content, mixed silicide of iron, cobalt or nickel and (c) up to 20 weight percent of at least one oxide, nitride, or silicate of an element of IUPAC groups 2, 3, 4, 13 or the lanthanide series. A method for making such a product is also disclosed.