Study On The Technology Of Wear-resisting Composite Coatings

Friction and wear are the important reasons for causing the failure of equipment parts, and composite plating technology as an important surface engineering technology, either can work as an surface strengthening technology, and can play as an important repair technology which not only makes the equipment parts restore to the right size, also improves the surface quality of equipment parts. This paper adopts composite plating technology generates coating layer on the surface of sample, the coating layer makes the surface hardness and wear-resisting performance improved greatly.By using contrast test methods, we succeed in making SiC particles have a better dispersibility by adding dispersant and with ultrasonic wave oscillation. That will make a solid foundation for the composite plating.This paper takes the hardness and current efficiency as evaluation standards to get the optimal processing parameters about the Ni-based, Fe-based and Fe/Ni-based composite plating with SiC powder by the design of orthogonal experiment and a single factor experiment. The optimal parameters are as follows:the Ni-based composite plating with temperature 50℃, current density 1A/dm2, n-SiC value 8g/L; the Fe based composite plating with temperature 40℃, current density 12A/dm2, n-SiC value 8g/L; the Fe/Ni-based composite plating with temperature 60℃, current density 1.5A/dm2, n-SiC value 8g/L. And three sorts of composite coating hardness value have been increased significantly than with no composite plating (150HV).The results of friction and wear test show that the Fe-based composite coating with nano SiC is much better than the two other composite coatings by the analysis of friction coefficients, weight loss and so on; The thermal shock trials indicate that the Ni-based composite coating with nano SiC performs much more inferior than the two other composite coatings by comparison of the surface roughness changes and the optical microscope analysis; The electrochemical corrosion test(EC test) show that the three kinds of composite coatings have excellent corrosion resistance through the analysis of the before and after surface metallographic photos.In the end of the paper, we have got three kinds of composite coating on the surface of internal combustion engine cylinder liner, through the friction and wear test, we've also got the same conclusion:the Fe-based composite coating with nano SiC have much more superior than two other composite coatings.