TC4表面WC/Ni-MoS_(2)钛基复合涂层组织与摩擦学性能

Organization and Tribological Properties of WC/Ni-MoS_(2) Titanium-based Composite Coating on TC4 Surface

拟在TC4表面合成Ti-S系自润滑耐磨熔覆层,并探究WC添加对涂层组织与摩擦学性能的影响,设计了TC4+Ni-MoS_(2)+xWC(x=5%、10%和15%)钛基材料体系,通过同轴送粉激光熔覆技术完成了涂层制备。研究表明,增加WC含量不利于改善涂层成形质量,但WC添加量变化并未影响涂层析出相种类,三种涂层均包括TiC、Ti_(2)Ni、Ti_(2)S和β-Ti基体;随着WC含量增大,TiC分布数量增多,粒径增大,生长形态由类球状逐渐演变为花瓣状;润滑相MoS_(2)未能在涂层中得到保留,其完全溶解后在钛基熔池体系下合成了与润滑相TiS等形态相似的条状相Ti_(2)S。三种WC含量的涂层显微硬度和耐磨性能均高于TC4基材,磨损机理均为磨粒磨损,但减摩性能均不低于TC4基材,说明原位Ti_(2)S相不具备自润滑功能;WC含量增加虽然有利于增大涂层的显微硬度和耐磨性能,但引起了涂层磨损面质量下降,摩擦系数波幅增大。

To synthesize Ti-S self-lubricating wear-resistant fused cladding on TC4 surface and to investigate the effect of WC addition on the coating organization and tribological properties,a titanium-based material system of TC4+Ni-MoS_(2)+x WC(x=5%,10%,and 15%)was designed,and the coatings were prepared by the coaxial feeding laser cladding technique.It was shown that increasing the WC content was not conducive to the improvement of the coating forming quality,but the change of WC addition did not affect the type of precipitated phase in the coatings,and the three coatings included TiC,Ti_(2)Ni,Ti_(2)S and β-Ti matrix;with the increase of the WC content,the distribution of TiC increased in number and particle size,and the growth morphology evolved from spherical to petal-like;the lubrication phase MoS_(2) was not retained in the coatings,and its complete dissolution synthesized under the titanium-based molten pool system with similar morphology to the lubricating phase TiS,etc.The microhardness and wear-resistant properties of the three WC content coatings were higher than those of the TC4 substrate,and the wear mechanism was abrasive wear,but the friction reduction performance was not lower than that of the TC4 substrate,which indicated that the in-situ Ti_(2)S phase did not have self-lubrication;the increase in the content of WC,although conducive to the increase in the microhardness and wear-resistant properties,but caused the coating to become more and more lubricated.Although the increase of WC content is favorable to increase the microhardness and wear resistance of the coating,it caused the decrease of the quality of the wear surface of the coating and the increase of the friction coefficient amplitude.