Reseach On The Preparation Of Micro-arc Oxidation Film On Titanium Ally TC4 Base On Low Current Density

Micro-arc oxidation is a new surface treatment technology developed in the recent years, which is mainly used in the aluminum, magnesim, titanium and other valve mental, consists of the complex physical, electrochemical, thermal chemical and plasma discharge. The micro-arc oxidation coating of metal surface has excellent wear resistance, corrosion resistance and other great characteristics, to a certain extent, which solves the critical problems of the key componentSpark discharge phenomenon with releasing a lot of heat occours in the Micro-arc oxidation process, so Micro-aro oxidation is the large comsuption. The current density which is used in the specimen generally is more than 10A/dm², because the power of MAO equipment is limited, which limits the scope of the MAO application.This Artical is based on the needs of the practical applications to study the preparationg of MAO on the titanium with no more than 1A/dm².Fist, study the reflection of electrolyte on the titatium ally MAO coating performance, to determine the value of the main agent of the phosphate, silicate and aluminum and then the optimal electrolyte component is obtained by orthogonal design. Second, by studying the reflection of electrical parameters on the MAO coating performance, to determine the value of electrical parameters, the optimal electrical parameters are obtained by orthogonal design. Last the optimal electrolyte component and the corresponding electrical parameters are obtained by comparation. Study the reflection of the electrolyte stability on the MAO coating properity.Study the reflection of nano-Al₂O₃ on the charateristics of the MAO coating. To establish the prediction model based on orthogonal design and the neural network that the nano-Al₂O₃ and electrical parameters reflect the MAO coating properity. Propose the quantitative method of calculating the pore area and the comparation of density of the looser and compact layer. Study the mechanism that addition Al₂O₃ improves the corrosion resistance by the AC impedance.By analysising the XRD figure of the MAO coating, chemical reactions are speculcated, the possibility of reaction is verified by thermodynamics, the reaction condition is deduced. The mechanism of two approches improving the corrosion resistance of the MAO coating is prosposed.