Content area
Abstract
Poor corrosion resistance of magnesium alloys remains a major obstacle to their extensive application. Phosphate conversion coating (PCC) is one of the most direct and effective strategies to enhance the corrosion resistance of magnesium alloys. To overcome the environmental damage of traditional phosphating technology, a PCC free of fluorine, chromium and nitrite was prepared in the present work. The effects of surface pre-activation process and preparation temperature on the surface morphology and corrosion resistance of PCC on ZK60 magnesium alloy were investigated. Surface pre-activation could significantly reduce the ultimate grain size of phosphate. At 90 °C, the prepared PCC showed perfect morphology and corrosion resistance. To better understand the phosphating nucleation and growth process, the surface and cross-sectional morphologies of PCC prepared for different times were observed. The phase composition of the prepared PCC was detected to be Hureaulite (Mn5(PO4)2(PO3OH)2·4H2O) and the coating growth mechanism was suggested in the end.
Details
1 Qilu University of Technology (Shandong Academy of Sciences), Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials, Advanced Materials Institute, Jinan, China (GRID:grid.443420.5) (ISNI:0000 0000 9755 8940); Chinese Academy of Sciences, Institute of Metal Research, Shenyang, China (GRID:grid.9227.e) (ISNI:0000000119573309)
2 Qilu University of Technology (Shandong Academy of Sciences), Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials, Advanced Materials Institute, Jinan, China (GRID:grid.443420.5) (ISNI:0000 0000 9755 8940); Qilu University of Technology (Shandong Academy of Sciences), Shandong Engineering Research Centre of Lightweight Automobiles Magnesium Alloys, Advanced Materials Institute, Jinan, China (GRID:grid.443420.5) (ISNI:0000 0000 9755 8940)
3 Qilu University of Technology (Shandong Academy of Sciences), Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials, Advanced Materials Institute, Jinan, China (GRID:grid.443420.5) (ISNI:0000 0000 9755 8940)