Research On Preparation And Properties Of FeS/Cu-Bi Copper-based Sliding Bearing Materials

In this paper,the non-toxic metal elements Bi and FeS with low-melting point are selected as the composite lubricating component.Considering the synergistic effect of FeS and Bi in antifriction and anti-adhesion,it is expected to replace the harmful element lead with FeS and Bi in the copper-lead bearing material,so as to acquire lead-free copper-based bearing material.Firstly,FeS/Cu-Bi copper-based alloy powder was prepared by mechanical alloying high-energy ball milling,and the lead-free FeS/Cu-Bi copper-based bearing materials were prepared by powder metallurgy.At the same time,the tribological properties of different materials under different mechanical conditions and different working conditions were studied,and the friction and wear mechanism of FeS/Cu-Bi copper-based bearing materials was analyzed.Study shows that the content of Bi and ball milling time both have a great impact on the mechanical and tribological properties of copper-based materials.With the increase of the content of Bi,the hardness of the material becomes smaller and smaller,and the relative density and crushing strength increase first and then decrease.While with the increase of ball milling time,the relative density and hardness of the material increase first and then decrease and the trend of crushing strength and impact toughness is getting smaller and smaller.The tribological properties of FeS/Cu-Bi copper-based materials containing Bi are better than those of FeS/copper-based materials,and the friction and wear resistance of the material is the best when the Bi content is 6%.Appropriate ball milling time can improve the antifriction and wear resistance of the material.However,when the ball milling time is too long,the work hardening of power will enhance,which will in turn reduce the friction and wear resistance of the material.The results show that the friction and wear properities of the material is best when the content of Bi is between 4 and 8% and the ball milling time is 10 hours.Bi and FeS have a good synergistic effect.During the friction and wear process,FeS and Bi aggregate and adhere to the surface of the material and the melting plate to form a lubricating transfer film,which has a good antifriction and anti-adhesion effect.However,Bi and FeS in the un-milled material are mutually divided and mutually agglomerated,and the quality of bonding with the matrix is poor,and the formation of the lubricating transfer film is incomplete and easy to peel off,which limits its antifriction and anti-adhesive ability.Appropriate ball milling time can effectively improve the uniform distribution of FeS and Bi,improve the bonding quality of FeS,Bi and matrix interface,and at the same time,the synergistic effect of Bi and FeS on antifriction and anti-adhesion get better.However,when the ball milling time is too long,the mechanical properties of the material are degraded,the support and stabilization of the lubricating transfer film are weakened,and the friction reduction effect is lowered.The appropriate increasing of the load is beneficial to improve the contact of the friction pair,promote the formation and stability of the lubricating transfer film,and improve the self-lubricating performance;however,when the load is too high,the damage to the lubricating transfer film is increased,and the tribological properties of the material is deteriorated.