高速钢表面HT-CVD TiC/TiCN复合涂层微观结构与耐磨性能研究

摘要

以TiCl4-CH4-N2-H2为反应体系,通过改变N2/CH2体积比(V(N2)/V(CH)),采用高温化学气相沉积法(HT-CVD)在高速钢基体表面制备不同微结构的TiC-TiCN复合涂层.分析了V(N2)/V(CH4)对TiCN层微观结构的影响规律以及TiCN层微观结构对复合涂层耐磨性能的影响机制,并研究了不同载荷下复合涂层的磨损行为.结果表明,随着V(N2)/V(CH4)的增加,TiCN涂层生长择优取向由(111)晶面转变为(200)晶面,涂层晶粒由长条状转变为锥状.当V(N2)V(CH4)=4∶1时,具有(111)择优取向的复合涂层硬度最高、耐磨性能最好;随着载荷的增加,复合涂层耐磨性能逐渐下降.当载荷≥20 N时,由于表面氧化层及碳转移膜的减摩-润滑作用削弱,导致复合涂层发生严重磨损,其磨损行为由磨粒磨损转变为粘结磨损.%Through changing the volume ratio of NfCH4,different microstructures of TiC /TiCN composite coatings were deposited by high temperature chemical vapor deposition (HT-CVD) according to TiCl4-CH4-N2-H2system.The effect of volume rate of N2/CH4(V(N2)/V(CH4)) on the microstructure of the as-deposited TiCN coating was analyzed,the effect of microstructure of TiCN layer on the anti-friction performance of the composite coating was investigated,and the effect of applied loads on the wear behavior of the composite coating was also studied.Results show that,with the increase of V(N,2)/V(CH4),the preferred growth direction of TiCN coating is transformed from (111) plane to (200) plane,and the profile of TiCN grain changes from lathlike to conoid.The composite coating with (111) preferred growth direction deposited at V(N2)/V(CH4) of 4∶1 exhibits the highest hardness value and the best anti-friction property.As the increase of applied loads,the anti-wear performance of composite coating decreases gradually.When the applied load is more than 20 N,the severe wear loss of composite coating occurs due to the weaken antifriction and lubrication effect of oxide layer and carbon transfer film formed on the coating surface,and its wear behavior changes from abrasive wear to adhesive wear.