Research On Tribological Properties Of FeS/Copper Base Bearing Materials

Lead is widely used in copper base sliding bearing materials, but lead is a harmful substance, which has serious harm to the human body and the environment. With the continuous enhancement of people’s awareness of environmental protection, the product of lead-free is the inevitable trend. In this paper, the anti-friction and anti-adhesion of FeS is used to replace the lead in the sliding bearing material of copper base; The FeS/copper-bearing materials were prepared by conventional powder metallurgy process, using X-ray diffraction and optical microscopy to observe and analyze its composition and microstructure, the porosity, hardness, density of copper base sliding bearing materials were tested, the friction and wear properties of FeS/copper base sliding bearing materials were tested by using the MM-200 tribometer, and using scanning electron microscopy, energy dispersive spectroscopy, X-ray photoelectron spectroscopy to analyze the mechanism of friction and wear.Research shows that the FeS has the characteristic of lubrication in the pressing process, when the FeS content is below 5%, with the increase content of FeS, the surface porosity of the material show a trend of decrease, when the FeS content exceeds 5%, due to the FeS and matrix are combined not closely, with the increase content of FeS, the surface porosity of material are increased, because the FeS particle is porous, with the increase content of FeS, the oil storage capacity of material is also improved. When the FeS content is less, it has dispersion strengthening effect on the matrix. However, if the content of FeS is excessive, the characteristics of its soft and slippage will be its dominant position, and the hardness will decrease.Under the dry friction conditions, the FeS particles can continuously gather to the friction surface, and then forming a layer of solid lubricating film, to ensure the FeS/copper base bearing materials have good anti-friction and wear-resisting performances. Under the condition of presoak oil dry friction, due to the FeS particle has the function of reserving oil, the material will spill more lubricating oil. Under the synergistic effect of the solid lubrication film and lubricating oil film, the anti-friction and wear-resisting performance of FeS/copper-bearing materials is very good. Under the condition of presoak oil lubrication, lubricating oil plays a leading role in reducing friction, the material with higher FeS content has more pores. Under the external load, lubricating oil is easy to leak from the pores, so it is not conducive to the stability of lubricating oil film. At the same time, when the FeS content is higher, the strength and hardness of the material is decreased and the material is easy to be deformed, which is also not conducive to the stability of the lubricating oil film. Under different loading conditions, the FeS has an optimum content, which makes the FeS/ copper base bearing material has a good anti friction and wear resistance. When Fes/ copper base bearing material and 45# steel friction occurs, hard asperities and the hard particles which are fallen off the material are easy to scratch the surface of copper based materials owning to the hardness of 45# steel, then the abrasive wear occurs; When the dual part is stainless steel, so the abrasive wear is slight due to the softness and adhesion of stainless steel, but adhesive wear is serious.