Study On The Anti-corrosion And Tribological Characteristics Of Cold Spray Coating On The Working Surface Of Hydraulic Piston Pump

Plunger pump is widely used in hydraulic power system,and the protection of the core component plunger is very important.In the marine working environment with a large number of corrosive media and organisms,the friction pairs formed between the outer surface of the plug and the inner wall of the plunger cylinder will cause serious friction and wear.At the same time,the electrochemical corrosion and biological fouling will occur on the outer surface of the plug,which will cause the damage of the plunger and the leakage of the liquid in the plunger pump,and affect the working efficiency and service life of the plunger.Based on reading a large number of relevant literature on anti-corrosion and wear-resistant coatings and surface processing methods,it is finally determined to use cold spraying technology to prepare Zn₆₅Al₁₅Mg₅ZnO₁₅5 and Zn₄₅Al₃₅Mg₅ZnO₁₅5 composite coatings.Starting from the analysis of the physical characteristics of the metal powder particles,it is found that the metal powder particles are mechanically mixed evenly and have high sphericity,which is more conducive to the deposition of the cold spraying coating.Zn₆₅Al₁₅Mg₅ZnO₁₅5 and Zn₄₅Al₃₅Mg₅ZnO₁₅5 composite coating samples were prepared by cold spraying technology.The thickness and hardness of the coating were measured.Scanning electron microscopy（SEM）was used to observe and analyze the microstructure of the coating,and energy dispersive spectroscopy（EDS）was used to characterize the elements of the composite coating.It was found that the microstructure of the composite coating prepared by cold spraying was compact without holes and cracks,and the powder coating was well mixed.Through the analysis of neutral salt spray test（NSS）and electrochemical workstation test,the datas show that the two composite coatings have good corrosion resistance and can effectively protect the substrate,and the Zn₄₅Al₃₅Mg₅ZnO₁₅5 composite coating has better corrosion resistance and durability.In addition,the mechanism of the whole corrosion process of the coating is analyzed,and the chemical equation is used to reflect the whole corrosion process.It is verified that Zn element is the first corrosion element of the coating,and the passivation film of the oxidation product generated after corrosion is conducive to slow down the corrosion rate,and the corrosion product will further corrode and dissolve in the later stage.Through the photocatalytic degradation test of the coating on methyl orange,it can be found that the two composite coatings have good photocatalytic performance,and the photocatalytic efficiency of Zn₄₅Al₃₅Mg₅ZnO₁₅5 composite coating is higher and the strong oxidation is better.In order to analyze the wear mechanism of the plunger,the friction and wear tests were carried out on the samples.The comparison of the friction and wear data shows that the Zn₄₅Al₃₅Mg₅ZnO₁₅5 composite coating has higher hardness and better wear resistance than the Zn₆₅Al₁₅Mg₅ZnO₁₅5 composite coating.The results show that the wear volume and wear amount of Zn₆₅Al₁₅Mg₅ZnO₁₅5 are larger than that of Zn₄₅Al₃₅Mg₅ZnO₁₅.According to the wear trace phase diagram and data in the friction and wear test,the wear amount of Zn₆₅Al₁₅Mg₅ZnO₁₅5 is larger than that of Zn₄₅Al₃₅Mg₅ZnO₁₅.The conclusion of friction and wear test is consistent with that of mathematical modeling.In addition,starting from the mechanism of corrosion and wear,the corrosion of the plunger surface in the corrosive medium and the friction and wear mechanism in the corrosive state are analyzed.The mathematical model of corrosion and wear shows that the quality of corrosion and wear is not a simple combination of corrosion and wear,but includes four processes:simple wear,corrosion promoting wear,simple corrosion and wear promoting corrosion.There is obvious interaction between corrosion and wear.In addition,using SolidWorks 3D modeling plunger pump,the working principle of plunger pump is analyzed.Combined with the working environment of the plunger,ANSYS static structure,ANSYS modal and other simulation analysis are carried out to explore the pressure of metal powder particles sprayed on the matrix,the displacement,stress,strain of the plunger surface,and the mode analysis of the plunger.The residual thermal stress between composite coating,zinc coating and aluminum coating is analyzed by ABAQUS simulation.The results show that the residual thermal stress between composite coating and matrix is smaller,and the tensile stress of coating is also the smallest.It is not necessary to select the single element coating of zinc and aluminum as the transition coating between coating and matrix.