陶瓷復(fù)合材料
( 國防科技大學(xué) 新型陶瓷纖維及其復(fù)合材料國防科技重點(diǎn)實(shí)驗(yàn)室， 長沙 410073)
摘 要: 以聚硅氧烷為先驅(qū)體， SiC為惰性填料， Al為活性填料， 考察了活性填料Al在聚硅氧烷轉(zhuǎn)化制備Si-O-C復(fù)合材料中的應(yīng)用。 研究發(fā)現(xiàn)： 600℃時，活性填料Al能與聚硅氧烷裂解產(chǎn)生的含碳小分子氣體反應(yīng)生成Al4C3， 800℃時能與N2反應(yīng)生成AlN； 這2個反應(yīng)同時伴有體積膨脹， 能有效彌補(bǔ)聚硅氧烷裂解時的線收縮。 活性填料Al的引入能起到增強(qiáng)作用； 含20%Al（體積分?jǐn)?shù)）的SiC/Si-O-C復(fù)合材料的彎曲強(qiáng)度是不含Al的1.36倍； 活性填料Al的引入能顯著改善SiC/Si-O-C復(fù)合材料的耐高溫和抗氧化性能， 但不能提高其抗熱震性能。
關(guān)鍵字: 活性填料； 鋁； Si-O-C陶瓷；先驅(qū)體裂解
derived silicon oxycarbide composites
ZHENG Wen-wei, HU Hai-feng
（ Key Laboratory of Advanced Ceramic Fibers and Composites,College of Aerospace and Materials Engineering,National University of Defense Technology, Changsha 410073, China）
Abstract: Polysiloxane loaded with SiC as inert filler and Al as active filler, was pyrolyzed in N2 to fabricate Si-O-C composites, and the processing and properties of the filled Si-O-C composites were investigated. Al fillers can react with hydrocarbon generated during polysiloxane pyrolysis at 600℃ and N2 at 800℃ to create Al4C3 and AlN, respectively. The volume expansions resulting from the two reactions are in favor of the reduction in linear shrinkage and the improvement in flexural strength of SiC/Si-O-C composites. The flexural strength of Al-containing SiC/Si-O-C composites is 1.36 times of that of SiC/Si-O-C composites without Al at an Al filler content of 20%. The addition of Al fillers can remarkably improve the high temperature resistance and the oxidation resistance of SiC/Si-O-C composites, but not the thermal shock resistance.
Key words: active filler； aluminum； silicon oxycarbide ceramics； preceramic polymer pyrolysis
