Research On Process Parameters And Performance Of Self-lubricating Coating By ESD

The Cu/BN and Cu/MoS2coating are prepared by the electric spark depositionprocess on the surface of carbide (YT15) and high speed steel (W18Cr4V) respectively,and the coating preparation process, phase composition, microstructure, thickness,hardness, friction and wear properties systematically studied in depth.Chemical compatibility and physical compatibility analysis are studied by usingthe method of thermodynamic. Through the chemical compatibility analysis, thecoating of the phase is predicted. Through the finite element simulation analysis, thephysical compatibility is analyzed between the coating and substrate material. What’smore, the temperature field distribution in single deposition is also analyzed atdifferent positions. The results show that there is a large difference in a single point ofdeposition temperature distribution in three directions. Among them, when thedeposition point moves on the coating line, temperature change at three direction showa linear relationship with the distance from the heat center distance, but the variation isdifferent. When the deposition point is located in the intermediate coating, thetemperature change is relatively similar in two mutually perpendicular directions, andthe temperature of the heat source with the distance from the center is linear.Cu/BN coatings preparing on the surface of hard alloy (YT15) is test by X-raydiffraction (XRD) and scanning electron microscope (SEM), the results show thatCu/BN coatings does not produce new substances during the deposition.When usingthe diameter2.2mm copper capillary tube as the electrode, the coating surface is themost smooth at the3files capacitance. The coatings thickness are measured by theoverlay gauge, and the results show that there is some relationship between thethickness and the deposition time of coatings, but the thickness of the coating is notincreased with the increase of deposition time. The friction and wear is tested on a pinon disc friction and wear testing machine, and the results show that the coating wearproperties is best at the3files capacitance, when using the diameter2.2mm coppercapillary tube and BN as the electrode. The wear is mainly dominated by abrasive wearon the grinding process, when the load is700g, and the rotate speed is400r/min. While Cu/MoS2coatings preparing on the surface of hard alloy (YT15) is test by X-raydiffraction (XRD) and scanning electron microscope (SEM), the results show thatCu/MoS2coatings produce new substances during the deposition. When using thediameter2.0mm copper capillary tube and MoS2as the electrode, the coating surface isthe most smooth at the3files capacitance. the result of friction and wear show that thecoating wear properties is best at the3files capacitance, when using the diameter2.2mm copper capillary tube and MoS2as the electrode.Cu/BN coatings preparing on the surface of high speed stee（lW18Cr4V）is test byX-ray diffraction (XRD), the results show that Cu/BN coatings does not produce newsubstances on the surface of the coatings during the deposition. It can be seen from theSEM picture that partial coatings exist cracks. When using the diameter2.2mm coppercapillary tube and BN as the electrode, the coating surface is the most smooth at the3files capacitance. By systematic analysis of the hardness between the substrate surfaceto the coatings surface, we can included that the hardness on the surface of coatings isthe minimum. Along the direction close to the substrate, the coating hardness increasesgradually, and the coatings hardness reach the maximum value in the boundarybetween the coating and the substrate. When the load is500g, and the rotate speed is400r/min, and the friction time is20minutes, and the diameter1.8mm copper capillarytube and BN are selected as the electrode, then the coatings wear properties is best.When MoS2is selected as the solid lubricant, the new substances can not be tested onthe coatings surface, and the preparation of the coatings under various parameters areslight defect. When the load is500g, and the rotate speed is400r/min, and the frictiontime is20minutes, the friction coefficient of coatings is the minimum, which prepareon the surface of high speed steel, and the diameter2.2mm copper capillary tube andBN are selected as the electrode.Cu/BN and Cu/MoS2self-lubricating coatings are prepared on high speed steelsurface with end face drilling method respectively, and the morphology, coatingthickness, friction and wear properties are studied. The results show that the coatingssurface is smooth, when the coatings are prepared on high speed steel surface withCu/MoS2. The wear are mainly abrasive wear for two kinds of coating.