Preparation, Characterization And Property Of The Microarc Oxidation Of Titanium And Titanium Alloys

MAO coatings have intensively attracted the attention of many research groups due to its desirable characteristics, especially the coatings on the substrates of titanium and its alloys. Recently years, the performances in all fields and application on the coatings fabricated by MAO have been developing and studying by many units in the world. Because MAO is a complicated process, which is controlled by multifactor, different technical parameters, as-deposited MAO coatings show various properties. Moreover, the experimental and theoretical results are not systematic or complete. Therefore, further research work on preparation and characterization of MAO coatings on the substrates of titanium and its alloys, which are extensively used in many various fields, is needed. In this thesis, evaluated as a new material, MAO coatings on the substrates of titanium and its alloys are studied systematically in which the effect of deposited parameters on coating properties is investigated. It is our goal to fabricate the MAO coatings with the outstanding characteristics. The coatings on titanium and its alloys substrates are prepared by means of a self-made industrial frequency power supply with a real data collecting system of electrical current and voltage. During experiments, the effect of basic deposited parameters on MAO coatings properties is studied, and the parameters are optimized. Simultaneously, the coatings with excellent properties are obtained in the optimized experimental conditions. On the basis of these, the effect of the electrical parameters on characterization of MAO coatings on pure titanium are studied by a self-made multifunctional MAO power supply.This thesis consists of three parts. In the first part, the coatings on TC4 titanium alloy substrate are fabricated under the condition of the constant voltage and current density. The variations of the electrics parameter against treatment time are studied during MAO process, and the effects of treating parameters on the coating characterization are also discussed. The results show that the current variations with treating time include obviously...