Study On SiC Particle Reinforced Of Micro-arc Oxidation Coatings Formed On AZ91D Magnesium Alloy

Micro-arc oxidation (MAO) of magnesium alloys is a plasma discharge that occurs at the metal/electrolyte interface when the applied voltage exceeds a certain critical breakdown value. This article in uses for reference had in the chemical reagent formula composition allocated proportion foundation, the reference preliminary attempt test result, through increases the SiC powder in the existing linear element oxidation formula composition (particle size≤5μm), and has carried on the optimization to its technological parameter, to the linear element oxidation compound film's characteristic which prepares has carried on the thorough discussion.In the electrolyte formula constituent, uses the existing silicate system's electrolyte formula, the increase enhancement body SiC powder (particle size≤5μm), and has carried on the optimization to this system's linear element oxidation electrolyte formula and the technological parameter, a good MAO composition of the electrolyte system for magnesium AZ91D alloy is found out: Na2SiO415g/L, NaOH 2g/L,KF 13g/L, SiC powders3 g/L; The best technological parameter is, constant flow pattern, frequency 600Hz, duty cycle 30%, oxidation time 50 minutes.In the film performance study part, the linear element oxidation compound film which and the linear element oxidation film which prepares in this electrolyte formula and under the technological parameter condition prepares under the same condition (in electrolyte has not joined the SiC powder) to carry on the comparison, the linear element oxidation compound film membrane thick even, sends the density to be high, degree of hardness high, the anti-corrosive performance and the wear resistant performance surpass the linear element oxidation film, carries on the SEM observation analysis to the linear element oxidation compound film and the linear element oxidation film's microscopic superficial appearance to discover: The film surface is the network structure which constitutes by many pores, but the former is more compact, the aperture to be small, the micro crack to be relatively few. Carries on the XRD phase analysis to the linear element oxidation compound film to discover: This film is mainly by Mg, MgO, Mg2SiO4 and SiC is composed. Carries on the EPMA element density change analysis to the linear element oxidation compound film to discover: In the film Mg, Si, C, the O element along designates in the straight line direction the density change situation. Carries on the EDS element content and the distribution analysis to the linear element oxidation compound film discovered: The oxidized time to elements and so on Si, C, O enters the oxidized film to be influential, as a result of the electric field to the element function and the adsorption result, causes along with the run time extension, in the magnesium alloy surface oxidation film this three kind of element content also obviously to increase.