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

Abstract

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 25 g/L, NaH2PO4 10 g/L, NaAc 20 g/L, time 5 min, and temperature 75 °C. After such treatment, the contact angle of magnesium alloy with 760E resin was 36.4°. When the concentration of KMnO4 was 25 g/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 5 wt% NaCl solution at 95 °C for 168 h. Results showed that there were no signs of corrosion on magnesium alloy surface.

Effect of Temperature on Corrosion Resistance of Layered Double Hydroxides Conversion Coatings on Magnesium Alloys Based on a Closed-Cycle System

“…Surface treatment has been, so far, one of the most effective and convenient ways of improving the corrosion resistance of magnesium alloys [12][13][14]. The porous oxide/hydroxide coatings formed on the surface of magnesium alloys are not able to protect anti-corrosion.…”