HANG Yu 1, 2, SONG Renguo 3
(1. School of Mechanical Engineering, Zhejiang Industry Polytechnic College, Shaoxing 312000, Zhejiang, China; 2. Key Lab of E &
M, Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China; 3. School of
Materials Science and Engineering, Changzhou University, Changzhou 213164, Jiangsu, China)
Abstract: Due to the high content of silicon in cast aluminum alloy, it is difficult to cause arc when using micro-arc oxidation to prepare coatings. In this paper, sodium hexametaphosphate, sodium hydroxide and sodium tungstate were used as electrolytes, and the microarc oxidation coatings were prepared with a bidirectional pulse constant-current source. The influence of different oxidation time on the microstructure of the coatings was studied by scanning electron microscope (SEM), X-ray diffraction (XRD) and stereo microscope. The results showed that the composite performance was optimized with the increase of the oxidation time, and the hardness, surface roughness,and density of the coatings prepared after 20min oxidation were the best.
Key words: micro-arc oxidation; aluminum alloy; oxidation time