Preparation Of Electroplated Coating And Fretting Wear Performance Test

Corrosive wear is a common form of failure on the surface of parts.More and more scholars pay attention to the study of anti-wear in corrosive environment.Zinc-nickel alloy coating has high corrosion resistance and wear resistance,and is widely used in metal protection.At present,most of the zinc-nickel alloy coatings are prepared by plasma implantation and spraying technology.The results from literature show that compared with plasma implantation and spraying technology,the electroplating process has the characteristics of low cost,saving materials and easy control of process parameters.Therefore,in this paper,a zinc-nickel alloy coating is prepared on the surface of stainless steel,and its corrosion and wear resistance wear performed by a fretting wear set-up.Based on the research of the exiting wear test equipment,the design scheme of the fretting wear set-up is proposed using modern design methods.The driving system,transmission system,loading system,fixing system,and the detection system have been designed in detail.The numerical model is built using 3D software.Then the parts were manufactured and assembled.Finally,the set-up was verified by comparing the measured data with a commercial wear test platform.In this paper,chemical electro-plating is used to prepare the mono-metal coating and the alloy coating on stainless steel surface,with the purpose of enhancing the corrosion and wear resistance of the substrate.The electroplating deposition mechanism was analyzed,and then the zinc coating,the nickel coating,and the zinc-nickel alloy coating were prepared.The adhesion of coating to the substrate was tested by a scratch test.The S-4800scanning electron microscope was used to observe and analyze the coating morphology and element content.The electrochemical workstation was used to test the corrosion resistance of the coating.At the end,the corrosion and wear properties of the coating were analyzed by the self-designed set-up.The results show that:(1)the prepared zinc-nickel alloy coating has strong bonding strength with the substrate.(2)The SEM results show that the micro-structure of the coating is dense,crack-free and smooth.The EDS results show that the Zn content in the zinc-nickel alloy coating is 69.53%,the Ni content is 13.17%,and the C content is 5.63%,O content is 5.38%,Si content is 4.11%,and Cr content is2.18%.(3)The minimum corrosion current density of the zinc-nickel alloy coating is2.65μA/cm~2,and the maximum polarization resistance is about 11800Ω/cm~2.The prepared zinc-nickel alloy coating has good corrosion resistance.(4)The friction coefficient of 304stainless steel changes greatly with the increase of the load.After the zinc-nickel alloy is coated,the friction coefficient becomes stable.Under the same load condition,the wear depth of the 304 stainless steel is higher than the wear depth of the zinc-nickel alloy.Furthermore,the depth difference becomes more and more obvious with an increase in load.It can be seen from the wear surface topography that as the load increases,the wear scar surface becomes rough.Finally,at the wear area,the cracks appear,and the coating peeled off.The main failure form of the coating is crack.