Study On Sulphur And Tribological Properties Of Iron Based Powder Metallurgy Materials

Iron based powder metallurgy materials are widely used in friction pairs because of its good self lubrication performance,such as sliding bearings and engine bushes.However,with the development of science and technology,the self-lubricating properties of iron-based powder metallurgy materials are not enough to meet the requirements of complex working conditions such as high temperature,high load and high speed.Therefore,it is urgent to improve the antifriction and wear resistance of iron-based powder metallurgy materials.For this reason,the low temperature chemical sulphation technology on the surface of iron-based powder metallurgy materials and the antifriction and anti adhesion properties and mechanism of the sulphide layer are studied.The composition of the formula is optimized,and the tribological characteristics of the sulphide layer and the mechanism of friction reducing and adhesion resistance are clarified.The initial test formula on the surface of Fe based powder metallurgy material of low temperature chemical sulfide is firstly used in friction coefficient of friction and wear test and the wear depth as the basis,through the control of single factor method of aluminizing agent formula was studied,and use the optimized formula of infiltration temperature,infiltration time of sulfur,sulfur sulphurizing before pickling activation time and substrate surface roughness sulfurizing of sulfide layer friction and wear properties of sulfide layer,then carry out different lubrication conditions,different loads and different speed conditions of the friction and wear properties,using scanning electron microscopy(SEM),X ray diffraction(XRD)micro device analysis of morphology and structure,infiltration of sulfide layer composition,distribution of elements and the morphologies of the worn surfaces after friction wear test and wear surface composition,analysis and research The mechanism of antifriction and wear resistance of sulfur permeable layer.The research shows that the test formulation and process conditions have an important influence on the wear and wear properties of sulphide coating.Under the optimized formulation and process conditions,sulphur reduction on the surface of iron-based powder metallurgy material can significantly improve its friction and wear resistance.Under the condition of oil lubrication with lubricating oil,sulfide layer can exert synergistic liquid-solid lubrication,friction condition is better than the effect of reducing friction and wearresistance;sulfide layer load in the lower layer play the better properties of antifriction and wear resistance,but when the load exceeds the infiltration capacity of sulfide layer when the sulfide layer will soon wear failure,very serious;forming an appropriate increase in the friction velocity contribute to the permeability between sulfur layer and a sample of the lubricating film,improve the wear resistant performance of Sulphurized specimens,but if the speed is too high will cause damage to the oil film,is not conducive to the lubricant film the stability of Sulphurized specimens increased wear.