CAJ | 학술논문

通过化学气相沉积在短碳纤维表面制备C/SiC复合涂层，然后采用凝胶注模法制备纤维体积分数分别为2%和4%的Cf/Si3N4复合材料，利用X射线衍射与扫描电镜对该材料的物相与组织结构进行分析，研究短碳纤维对Si3N4陶瓷力学性能的影响。结果表明：随碳纤维体积分数增加，Cf/Si3N4复合材料的密度和抗弯强度降低，但断裂韧性明显提高。当纤维体积分数为4%时，材料的断裂韧性达到8.91 MPa·m1/2，比氮化硅陶瓷提高1.6倍，材料主要由长柱状的β-Si3N4基体、C/SiC涂层及碳纤维组成，碳纤维表面的C/SiC双涂层可防止高温下碳纤维与氮化硅基体发生反应，使碳纤维与氮化硅基体界面结合良好，以提高材料韧性并保证有合适的强度，满足功能材料在一定条件下的使用要求。
통과화학기상침적재단탄섬유표면제비C/SiC복합도층，연후채용응효주모법제비섬유체적분수분별위2%화4%적Cf/Si3N4복합재료，이용X사선연사여소묘전경대해재료적물상여조직결구진행분석，연구단탄섬유대Si3N4도자역학성능적영향。결과표명：수탄섬유체적분수증가，Cf/Si3N4복합재료적밀도화항만강도강저，단단렬인성명현제고。당섬유체적분수위4%시，재료적단렬인성체도8.91 MPa·m1/2，비담화규도자제고1.6배，재료주요유장주상적β-Si3N4기체、C/SiC도층급탄섬유조성，탄섬유표면적C/SiC쌍도층가방지고온하탄섬유여담화규기체발생반응，사탄섬유여담화규기체계면결합량호，이제고재료인성병보증유합괄적강도，만족공능재료재일정조건하적사용요구。
Carbon fiber reinforced silicon nitride matrix composites (Cf/Si3N4) with short carbon fibers of 0%,2% and 4%(volume fraction)were prepared by gel-casting . The phase composition and microstructure of Cf/Si3N4 were studied by XRD and SEM. The effect of volume fraction of short carbon fiber on mechanical properties of the composites was investigated. The results show that: with increasing the content of short carbon fiber, the density and bending strength of Cf/Si3N4composites decrease, while the fracture toughness increases obviously. The fracture toughness is 8.91 MPa·m1/2 which is 1.6 times higher than that of single phase silicon nitride ceramics when the volume fraction of short carbon fibers is 4%. The composite is mainly composed of long cylindricalβ-Si3N4 matrix, C/SiC coatings and carbon fiber. The C/SiC double coating can prevent the reaction between carbon fiber and SiC matrix, which is beneficial to the bonding of the interface, and then increasing toughness and providing suitable strength.