Research on potassium permanganate-phosphate treatment of magnesium alloy surface and fiber/magnesium alloy composite laminate

摘要

Firstly, the influence of potassium permanganate-phosphate treatment on surface topography and wettability of AZ31B sheet was studied in this work. Then, the fiber-reinforced resin/magnesium alloy composite laminate was prepared, and its properties were measured. Results showed that the concentration of KMnO4 had a significant influence on the contact angle of AZ31B sheet with resin. The optimum process parameters were as follows: KMnO4 25g/L, NaH2PO4 10g/L, NaAc 20g/L, time 5min, and temperature 75 degrees C. After such treatment, the contact angle of magnesium alloy with 760E resin was 36.4 degrees. When the concentration of KMnO4 was 25g/L, a uniform and compact conversion coating formed. Component analysis showed that the conversion coating mainly consisted of phosphate and oxides of Mg, Zn, and Ca. After the optimum process of potassium permanganate-phosphate treatment, the magnesium alloy sheet was used for the preparation of fiber reinforced resin/magnesium alloy composite laminate. At last, the corrosion resistance of such composite laminate was tested in 5wt% NaCl solution at 95 degrees C for 168h. Results showed that there were no signs of corrosion on magnesium alloy surface.