碳界面层制备工艺对SiC_f/SiC材料力学性能的影响  

Effect of Fabrication Process of Carbon Interlayer on Mechanical Properties of SiC_f/SiC Composites

作　　者：于新民[1] 周万城[1] 郑文景[1] 赵锴[1] 罗发[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710016

出　　处：《稀有金属材料与工程》2009年第A02期462-465,共4页Rare Metal Materials and Engineering

摘　　要：用低压化学气相沉积(LPCVD)法,以丙烯(C3H6)为碳源,氮气(N2)为稀释气制备了2.5维连续碳化硅纤维增韧碳化硅(SiCf/SiC)复合材料的碳界面层,其厚度为～0.1μm。研究了不同丙烯含量(体积分数,下同)(60%,50%,45%)对碳层形貌、微观结构及SiCf/SiC力学性能的影响。结果表明:当C3H6含量为60%时,热解碳层表面光滑,石磨化度高;当C3H6为50%和45%时,碳层粗糙,有很多较大颗粒存在,石磨化度低。3种复合材料的弯曲强度差别不大,分别为303,311和320MPa。然而,当C3H6含量为60%时,材料韧性断裂,断裂功高;为50%和45%时,材料脆性断裂,断裂功低。不同的纤维拔出滑移阻力是SiCf/SiC断裂行为不同的原因。Pyrocarbon interlayer of 2.5-dimension silicon carbide fiber reinforced silicon carbide composites was prepared by low pressure chemical vapor deposition （LPCVD） method using propylene as carbon source and nitrogen as diluent gas. The thickness of the interlayer is about 0.1μm. The effects of propylene content （60%, 50%, 45%） on the morphology, microstructure of the carbon coating and the mechanical properties of the composites were studied. The carbon coating has smooth surface, high graphitization degree when the propylene content is 60%; rough surface, low graphitization degree when the content is 50% and 45%. There is little difference between the flexural strength （303, 311 and 320 MPa） of the composites. However composite has a high work of fracture and fractures in a non-catastrophic mode when propylene content is 60%; a low work of fracture and fractures in a catastrophic mode when the content is 50% and 45%. Different interracial sliding resistances is the reason for the different fracture behaviors of the composites.

关 键 词：界面层 力学性能 SICF/SIC 

分 类 号：TB332[一般工业技术—材料科学与工程]