WC-(W,Cr)_2C-Ni/Ag复合涂层的制备及摩擦学性能

针对众多运动部件存在严重的摩擦磨损问题,使用大气等离子喷涂(APS)设备在1Cr18Ni9Ti不锈钢金属基材上喷涂制备WC-(W,Cr)2C-Ni和WC-(W,Cr)2C-Ni/Ag两种防护涂层,使用CSM摩擦磨损试验机考察两种涂层在室温下与Si3N4球配副时的滑动摩擦磨损性能。结果表明:Ag相的添加可明显降低涂层在干摩擦条件下的摩擦因数,并能减轻涂层的磨损程度;APS制备的WC-(W,Cr)2C-Ni/Ag复合涂层不仅具有优良的自润滑性能,而且具有极佳的耐磨性能,有望作为一种新型耐磨自润滑涂层材料。     

Microstructure and Tribological Properties of TiB2/TiB/TiNx（x=1,0.3）/Ti Composite Coating Produced on Pure Ti by Laser Surface Alloying

TiB2/TiB/TiNx(x=1,0.3)/Ti composite coating was prepared on pure Ti by laser surface alloying by using powders of boron as starting materials.The composite coating was examined by X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM)and scanning electron microscopy(SEM).The friction and wear properties of the composite coating were examined using a pin-on-disk tester under dry sliding wear condition.The results showed that the top surface of the composite coating was mainly composed of TiB2,TiB,TiN0.3,TiN and Ti phases,while the interface of the composite coating was composed of TiB and Ti phases.The composite coating showed sticklike structure near the top surface,and dendrites structure near the interface.The friction and wear test showed that the composite coating had better wear resistance than pure Ti due to their higher microhardness than that of pure Ti substrate.     

超重力场反应加工自增韧（Ti,W）C-TiB2凝固陶瓷刀具材料研究

采用超重力场反应加工技术制备出用于高速切削刀具的自增韧(Ti,W)C-TiB2凝固陶瓷。XRD、FESEM与EDS分析表明,(Ti,W)C-TiB2凝固陶瓷主要由大量细小的TiB2片晶及形状不规则的(Ti,W)C相构成,且TiB2片晶的形成是由其低生长速率的小平面晶体特性所致,而(Ti,W)C的晶体形貌则是由其高生长速率的非小平面晶体特性形成的。陶瓷相对密度、维氏硬度、弯曲强度及断裂韧性分别为98.3%、20.8GPa、(610±25)MPa与12.5MPa·m0.5。FESEM断口分析及裂纹扩展路径观察发现,(Ti,W)C-TiB2凝固陶瓷增韧是通过小尺寸TiB2片晶的裂纹偏转、裂纹桥接及摩擦互锁协同作用予以实现,而陶瓷的优异耐磨性主要取决于高硬度、高模量的细小TiB2基体相片晶。     

Cr3C2-25%（Ni,Cr）超音速火焰喷涂层的耐磨及耐蚀性能研究

采用超音速火焰(HVOF)喷涂技术在奥氏体不锈钢上制备了Cr3C2-25%(Ni,Cr)金属陶瓷涂层。采用光学显微镜、扫描电镜、能谱仪、X射线衍射仪、高速高温摩擦磨损试验机和电化学分析仪研究了涂层的显微组织、相结构、耐磨损和耐腐蚀性能。结果表明,该金属陶瓷涂层主要由(Ni,Cr)相、Cr3C2和Cr7C3组成,而且致密、硬度高,与基材结合牢固。涂层的高温磨损可分为黏结相切削和随后的碳化物剥落两个阶段,碳化物的剥落对涂层的磨损起主导作用。涂层在3.5%ZnCl2溶液中具有优良的耐蚀性,其腐蚀产物中含Ni、Cr元素而无Fe的氧化物,说明涂层对基体具有良好的保护作用。