Effects of Nano-SiO_2 in Electrolytes on Surface Properties of Micro-arc Oxidation Ceramic Coatings Formed on New Casting Aluminum Alloy

摘要

Ceramic coatings were fabricated on a new casting aluminum alloy during micro-arc oxidation by mixing nano-SiO_2 into the phosphate electrolyte. The effects of nano-SiO_2 in electrolyte on thickness, hardness and microstructure of the ceramic coatings were analyzed. The results show that nano-SiO_2 is deposited on the surface layer of the ceramic coatings in micro-arc oxidation process. The compactness of the coatings is thus improved. Both the thickness and hardness of the ceramic coatings increase a lot. The optimal addition amount of nano-SiO_2 in the electrolyte is 3 g/L.