基于耦合机制的宽温度自润滑陶瓷刀具材料

摘要

采用真空热压烧结工艺,制备TiB2/(W,Ti) C/Ag(TWA)双润滑机制耦合从低温到高温均具有润滑性能的陶瓷刀具材料.X射线衍射(XRD)分析表明烧结过程中各组分化学相容性较好,断口形貌扫描电子显微镜(SEM)照片显示润滑剂Ag不仅能有效填充晶粒间隙,还能增强晶粒间黏结强度.以TiB2/(W,Ti)C(TW)作为对比进行摩擦磨损实验,结果表明:室温下磨损表面均出现轻微机械犁沟,随着温度升高,TWA磨损表面形成富含润滑剂Ag的润滑膜,能有效减少摩擦系数与磨损量,400℃时其磨损量仅为TW磨损量的一半,TW、TWA主要磨损机制分别为磨粒磨损和黏结磨损.TiB2在700℃原位生成的反应膜能提高复合材料减磨与耐磨性能,TW、TWA磨损机制主要为轻微磨粒磨损和氧化磨损.%TiB2/(W,Ti)C/Ag (TWA) coupling mechanisms ceramic tool material possessing the lubricity from room temperature to 700℃ was prepared by the hot pressing sintering.X-ray diffraction patterns showed that the composites with wide chemical compatibility in sintering possess.It can be seen from scanning electron microscope (SEM) photographs of fracture surfaces that lubricant Ag can not only fill into the gap between (W,Ti)C(TW) and TiB2 grains,but also enhance the bonding strength.Friction and wear testing results indicated that mechanical furrows exist in TWA and TW worn surface at room temperature.With increasing temperature,the lubricant Ag was smeared on TWA worn surface and they exhibit lower friction coefficient,only a half of that of the TW ceramic.Abrasive wear and adhesive wear are found dominant in both TW and TWA.The properties of antifriction and wear resistance can be improved by in-situ generated reaction film of TiB2 at 700℃,mild abrasive wear and tribo-oxidation are the dominant wear mechanisms in TW and TWA.