Effects of Duty Cycles on Microstructure and Properties of Micro-Arc Oxidation Films Prepared on SiCp/Al Based Composite Materials

Abstract

Using NaAlO2 + NaOH as the electrolyte system, under constant pressure mode, the volume fraction of SiC was 45%, and the particle size was 5 μm, the surface of SiCp/Al based composite material was subjected to micro-arc oxidation treatment, and the effect of duty cycle on the microstructure and properties of the micro-arc oxidation film of SiCp/Al based composite material was studied. SEM was used to analyze the morphology of micro-arc oxidation film under different duty cycles. The phase composition of the film was studied by X-ray diffractometry. The roughness, micro-hardness and bonding force of the film were analyzed by roughness meter, Vickers hardness tester and scratch meter. The corrosion resistance of the film was studied by electrochemical workstation. Results showed that with the increase of duty cycle, the micro-arc oxidation film became continuous, the thickness showed an increasing trend, the roughness gradually increased, and the porosity gradually decreased. The duty cycle had a certain effect on the phase composition of micro-arc oxidation film. The adhesion between the micro-arc oxidation film and the substrate of SiCp/Al based composite materials first increased and then decreased with the increase of the duty cycle. The micro-arc oxidation film prepared under different duty cycles all improved the corrosion resistance of SiCp/Al based composite materials. The corrosion resistance of SiCp/Al based composite materials was the best when the duty cycle was 70%.

Keywords

• sicp/al based composite materials|micro-arc oxidation|duty cycle|microstructure|corrosion resistance