Papers by Author: Li Kun Jiang

Abstract: Microarc oxidation coatings were prepared on the surface of AZ31 magnesium alloy profiles. Oxidation time of the coatings was between 5min-10min. The phase structure, surface morphology and corrosion resistance of the coatings were investigated using SEM, XRD, copper sulfate spot test and polarization curve test. The results indicate: the main phase compositions of the microarc oxidation coatings are MgO, Mg₂SiO₄ and MgSiO₃; with increasing pulse voltage, the micropore diameter of the coating surface becomes larger, the micropore number reduces and the coating surface roughness increases; the corrosion current density of magnesium alloy reduces significantly after microarc oxidation treatment. The pulse voltage of microarc oxidation should be controlled between 240V-360V to obtain the best corrosion resistance.

Abstract: Long route and high inclusion content are two common problems existing in the present process for magnesium alloys. To solve these problems, a new process technology, in which the crystalline magnesium is used as the raw material, is developed. The process is melting flux→ adding raw materials in batches → stirring→ holding→ pouring (MASHP). The mechanisms of protection and purification mechanisms are also analyzed. The results show that the MASHP process has high protection and purification effects on magnesium alloys. By the in-batches addition mode of raw materials, no oxidation and evaporation loss of magnesium produce during heating and melting, and the inclusions that self-contained in the crystalline magnesium and that produced by oxidation during heating and melting can be minimized. High quality magnesium alloys can be produced by the new process.