Microstructure And Properties Of Stellite Alloy Coating By Electro-spark Deposition

Electro-spark surface deposition technology can improve surface property ofmaterials, save resources and energy and reduce environmental pollution, therefore ithas been widely appreciated. Due to the advantages of the low substrate temperature,firmly bonded between coating and substrate deposition, deposition processing complexparts and high input-output ratio, this technique becomes one of the rapid developmenttechnologies in recent years.In this investigation, by utilizing a new electro-spark deposition equipment. Steelssurface are deposited by Stellite6alloy electrode. The microstructure, phaseidentification and microhardness of the deposition layers were examined by usingmicroscope, scanning electron microscopy (SEM), X-ray diffraction (XRD) andmicrohardness instrument. Moreover, through friction tests and thermal fatigue tests, theproperty for samples of resistance to friction and thermal fatigue were analyzedsystematically.The test results show that many dense deposition points and discharge pitsconstitute the deposited coating of uneven surfaces. The coating of Stellite6alloy has agood metallurgical combination with the H13steel substrate. Electro-spark depositionparameters have an impact on the deposition of the coating surface roughness andthickness. XRD patterns of the contrast can be found that the structure of the coatingcomposition obtained by different processes is analogous. The coatings are consisted ofM7C3and Co-based solid solution, there may be other phases, because some of thediffraction peaks has not yet been determined. Stellite6alloy coating of the multi-sectional microhardness measurements performed, the hardness of the alloy coatingsurface was significantly improved, the average hardness of Stellite6alloy coating isabout572~637HV, which is2times higher than that of steel substrate. By somefriction wear tests, Stellite6alloy coating have excellent wear resistance. The studyfound wear resistance will become better when deposition capacitance increase.Samples which are deposited in the large-capacity will appear coating off by thermalfatigue tests200cycles, but only a small area of the coating peeling off, this state until1600times. Coatings which are deposited in small capacity will preserve intact bythermal fatigue tests from200cycles to1600cycles.