添加不同固体润滑剂铁基合金激光熔覆涂层的干滑动摩擦磨损性能

Dry Sliding Friction and Wear Properties of Fe-based Alloy Laser Cladding Coatings Added with Different Solid Lubricants

采用激光熔覆技术在CL60车轮钢表面分别制备不同含量WS_(2)(质量分数0~8.0%)和CaF_(2)(质量分数5.0%)固体润滑剂以及不同含量h-BN(质量分数0~2.0%)和CaF_(2)(质量分数0~2.0%)固体润滑剂的铁基合金涂层,对比研究了添加不同固体润滑剂铁基合金涂层的显微组织以及干滑动摩擦磨损行为和磨损机制。结果表明:所有涂层均主要由树枝晶和共晶组织组成,表面硬度均达到约800 HV,约为CL60钢的2倍。随着WS_(2)含量的增加,WS_(2)+CaF_(2)/铁基合金涂层的摩擦因数降低,磨损质量损失先降低后基本稳定,当WS_(2)质量分数为6.0%时,磨损质量损失最低,与未添加固体润滑剂的铁基合金涂层相比降低了26.7%,此时孔隙最少,磨损表面损伤轻微,磨损机制为磨粒磨损。随着h-BN含量的增加以及CaF_(2)含量的降低,h-BN+CaF_(2)/铁基合金涂层的摩擦因数与磨损质量损失均先降后增,且当CaF_(2)和h-BN的质量分数均为1.0%时,稳定摩擦因数与磨损质量损失均最小,与未添加固体润滑剂的铁基合金涂层相比,分别降低了32.7%和33.3%,此时晶粒最细小,组织最为致密,磨损表面以细小磨痕为主,磨损机制为轻微的磨粒磨损。

Fe-based alloy coatings with different content of WS_(2)(mass fraction 0-8.0%)and CaF_(2)(mass fraction 5.0%)solid lubricants and different content of h-BN(mass fraction 0-2.0%)and CaF_(2)(mass fraction 0-2.0%)solid lubricants were prepared on the surface of CL60 wheel steel by laser cladding technique,respectively.The microstructures of Fe-based alloy coatings added with different solid lubricants as well as the dry sliding friction and wear behavior were investigated.The results show that all coatings were mainly composed of dendritic and eutectic structures,and the surface hardnesses all reached about 800 HV,which was about twice as much as that of CL60 steel.The friction factor of WS_(2)+CaF_(2)/Fe-based alloy coating decreased with the increase of the content of WS_(2),and the wear mass loss first decreased and then was basically stabilized.When the mass fraction of WS_(2) was 6.0%,the wear mass loss was the lowest,which was reduced by 26.7%compared with that of the Fe-based alloy coating without solid lubricant;at this time,the pore structure amount was the least,the damage of the wear surface was slight,and the wear mechanism was abrasive wear.With the increase of h-BN content and the decrease of CaF_(2) content,the friction factor and wear mass loss of h-BN+CaF_(2)/Fe-based alloy coating both decreased first and then increased,and when the mass fractions of CaF_(2) and h-BN were both 1.0%,the stabilized friction factor and the wear mass loss were the smallest,which were reduced by 32.7%and 33.3%,respectively,compared with those of the Fe-based alloy coating without solid lubricant;at this time,the grain was the finest,the microstructure was the most dense,the wear surface was dominated by fine abrasions,and the wear mechanism was slight abrasive wear.