Abstract:
After adding different content of Na
2CO
3 and C
6H
12O
6 into NaOH-Na
2SiO
3-Na
2B
4O
7 basic electrolyte, AZ31 magnesium alloy was treated by direct current anodizing and then the microstructure and corrosion resistance in neutral salt spray of the magnesium alloy anodized film were studied. The results show that all magnesium alloy anodized film consisted of MgO and Mg
2SiO
4 phase. After adding Na
2CO
3 and C
6H
12O
6 into electrolyte, the micropores evenly distributed on the surface of the anodized film, and the size decreased; the thickness of the anodized film increased. When the mass concentration of Na
2CO
3 increased from 10 g·L
-1 to 30 g·L
-1, the size of micropores increased, and the thickness of anodized film decreased. When the mass concentration of C
6H
12O
6 increased from 5 g·L
-1 to 15 g·L
-1, the size of micropores decreased, and the thickness of anodized film increased. The main corrosion form of magnesium alloy anodized film was pitting, which presented a distribution of fluvial pattern. After adding 10 g·L
-1 Na
2CO
3 into the electrolyte, the micropores had the smallest size with the diameter of 1-3 μm, and the thickness of the anodized film reached 16 μm; the anodized film had relatively good corrosion resistance.