Process parameters optimization of increasing depositing rate for jet electrodeposition of engine cylinder

Abstract: The cylinder is an extremely important easily wearing part of a tractor engine, whose service life and production cost are directly affected by the wear resistance of the component. With excellent wear resistance, corrosion resistance, and greater hardness, a Ni-P alloy deposited layer can significantly enhance the service life and reliability of the cylinder, and the capability and quality of the tractor engine can be improved. The lower limiting current density of the traditional electrodeposited Ni-P alloy method leads to a lower depositing rate and lower production efficiency. Jet electrodeposition has been developed in recent years, which can significant increase the depositing rate because the jet electrolyte can accelerate the transfer process of the electrodeposition material and augment limiting current density. So jet electrodeposition is a type of high-velocity, selective electrodeposition technique with high deposition current density and high velocity. Furthermore, optimization of the process parameters of jet electrodeposition is the way to further increase the depositing rate. In this paper, technological experimentation is investigated by using a custom design of JMP to optimize process parameters of jet electrodeposition. The JMP software is Six Sigma statistical software developed by SAS, which is a professional statistical analysis tool. The JMP software can be used for processing data and designing of experiments. To the best of our knowledge, there is currently no report about applications of JMP in electrochemical use domestically. Voltage, electrolyte temperature, dipolar space, flow velocity of electrolyte, and dipolar relative velocity are the influence factors, and the depositing rate of deposited layers is the experimental index, and the relationships between the experimental index and the influence factors are analyzed through the response surface analysis method and sub-stepping method. The quadratic regression mathematical models that described the relations between the experimental index and the influence factors were established. The optimal technological parameters for depositing rate of a deposited layer were obtained through conducting a multivariable function optimization by the method of a quadric spindle gradient. The results suggest that JMP software can obtain more accurate optimal values by calculating than by orthogonal test. Voltage, electrolyte temperature, dipolar space, and dipolar relative velocity affect the depositing rate of a deposited layer markedly. The quadratic term of dipolar space have a high-impact on the surface effect of the depositing rate. And furthermore, voltage and flow velocity of the electrolyte, electrolyte temperature and flow velocity of electrolyte, flow velocity of electrolyte, and dipolar relative velocity have interactive effects on the changes of the depositing rate. The quadratic regression mathematical models reach a significant level and the equation has good fitting effects. So the models can be applied to predict the depositing rate of a deposited layer. The response surface methodology obtained the influences of voltage, electrolyte temperature, dipolar space, flow velocity of the electrolyte, and dipolar relative velocity on depositing rate of a deposited layer. And the optimal parameters are as follow: voltage of 15V, electrolyte temperature of 72℃, dipolar space of 1mm, flow velocity of electrolyte of 1.2 m/s, and dipolar relative velocity of 170 mm/min. Under these conditions, the depositing rate of a deposited layer is 79.13 μm/min and the quality of the deposited layer is better. The depositing rate of jet electrodeposition is about 130 times that of a traditional electrodeposition, and use of jet electrodeposition improves production efficiency. It can help to promote the development of high-speed plating.