C／C—SiC复合材料的反应熔渗法制备与微观组织.pdf

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1、C／C—SiC复合材料的反应熔渗法制备与微观组织赵彦伟孙文婷李军平刘宏瑞张国兵(航天材料及工艺研究所，先进功能复合材料技术重点实验室，北京100076)文摘采用无压反应熔渗法在1550℃下将熔融si或Si。Zro浸渗入多孔C／C预制体中制备了高致密的C／C—SiC复合材料。系统研究了多孔C／C预制体中酚醛树脂热解碳(PIP—C)和化学气相渗透碳(CVI-C)对反应熔渗si或si0．qzr0的浸渗行为、反应程度、物相成分和微观组织的影响。结果表明：熔融si或si0．9zr0．完全渗入到相邻碳纤维柬间的大孔和碳纤维形成的小孔中，多孔PIP—C／C预制体较易浸渗，且反应较充分，熔渗s。zrn后复合材

2、料中除了生成大量SiC外，还有少量ZrC和ZrSi生成，未发现游离Si。多孔PIP-C／C预制体中部分碳纤维与熔体反应，损伤纤维，而多孔CVI—C／C预制体中的沉积碳仅与熔体反应生成了一薄层，很好地保护了碳纤维，保持了碳纤维的高性能。提出反应熔渗制备C／C—SiC复合材料的形成机制：由初期的溶解一沉淀控制和后期的C向SiC层扩散控制为主。关键词多孔C／C预制体，C／C—SiC复合材料，反应熔渗法，微观组织，化学气相渗透PreparationandMicrostructureofC／C——SiCCompositesbyReactiveMeltInfiltrationZhaoYanweiSunWe

3、ntingLiJunpingLiuHongruiZhangGuobing(ScienceandTechnologyonAdvancedFunctionalCompositesLaboratory，AerospaceResearchInstituteofMaterials＆ProcessingTechnology，Beijing100076)AbstractAhighrelativedesityC／C-SiCcompositeswerepreparedbypressurelessreactiveinfiltrationofmol-tenSiorSi0Zr01alloyintotheporousC

4、／Cpreformat1550~2．EffectsofdifferentcarbonmatrixesofporousC／C．9．preformincludingpyrolyticcarbonandchemicalvapordepositedcarbononthebehaviorsofmeltSiorSio9Zr01alloy．infiltrationintotheporousperform，thedegreeofreaction，thereactionphasescontentsandmicrostructureswerein‘vestigated．Theresultsshowedthatth

5、emoltenSiorSi0Zro1alloywasinfiltratedintothelargeporesamongadjacent．9．carbonfiberbundlesandsomesmallporesamongcarbonfibers．ThemeltswereinfiltratedmoreeasilyintotheporousC／Cpreformwithpyrolyticcarbonandreactedcompletelybetweenpyrolyticcarbonandmelts．ThecompositewascomposedofSiC，ZrC，ZrSi2phasesandwith

6、outfreeSi．SomecarbonfibersreactedpartiallywithmeltintheporousC／Cpreformwithpyrolyticcarbon，whichleadedtopotentialdamageofthecarbonfibers．However，thechemicalva—pordepositedcarbonofoutersurfaceofthecarbonfiberonlyreactswithinfiltratingmeltstoformathinSiClayer，whichprotectedcarbonfibersandmaintainedthe

7、improvedperformances．ThemicrostructuralformationmechanismoftheC／C-SiCcompositespreparedbyreactivemeltinfiltrationwasproposed：theformationoftheearlystagewascon。trolledbysolution—precipitation，andthesub