多孔C/SiC复合材料的制备及其性能  

Fabrication and properties of porous C/SiC composites

作　　者：吉洪亮[1,2] 张长瑞[1] 周新贵[1] 曹英斌[1] 

机构地区：[1]国防科技大学航天与材料工程学院CFC国防科技重点实验室,湖南长沙410073 [2]中国空气动力研究与发展中心超高速空气动力研究所,四川绵阳622663

出　　处：《新型炭材料》2011年第2期145-150,共6页New Carbon Materials

基　　金：国家863计划(2002AA724064)~~

摘　　要：以W丝作为成孔剂,采用孔隙预置技术制备了发汗多孔C/S iC复合材料,对其孔隙结构进行表征,研究了材料的力学性能和渗透行为。结果表明:采用孔隙预置技术能够有效的控制多孔C/S iC材料开孔率和孔隙结构,其孔隙主要由W丝去除后形成的直通孔组成,开孔率决定于W丝的体积含量,所制备的材料具有良好的力学性能和渗透性能。其弯曲强度达到358M Pa、弯曲模量达到124GPa,断裂韧性达到16.7M Pa.m1/2,空隙率为23.5%,渗透率为1.02×10-3mm2,材料表现为韧性断裂模式,其孔隙的存在并没有对材料的力学性能产生明显的影响。Preforms made of carbon fibers and sacrificial tungsten fibers as a pore forming agent were repeatedly infiltrated with polycarbosilane and pyrolysed for 14 cycles,followed by aqua regia leaching to remove the tungsten fibers to form porous C/SiC composites.The pore structure,mechanical properties and permeability of the porous C/SiC composites to water and kerosene were respectively studied by a scanning electron microscope,a universal materials testing machine and home-made permeation equipment based on a fluid flow model in capillaries.Results showed that the pores of the porous C/SiC composites were mostly straight and that the open porosity can be controlled by the volume fraction of tungsten fibers used.The bend strength,Young＇s modulus and fracture toughness were 358 MPa,124 GPa and 16.7 MPa·m1/2 respectively when the open porosity of the composite was 23.5%.The fluids permeated through the porous C/SiC composites by linear laminar flow（the osmosis rate value is 1.02×10-3 mm2）.The composites exhibited tough fracture behavior and the presence of pores didn＇t lead to a significant deterioration of their mechanical properties.

关 键 词：多孔C/SiC复合材料 孔隙预置技术 开孔率 渗透率 

分 类 号：TB332[一般工业技术—材料科学与工程]