The Surface treatment of Aluminum Alloy Die casting parts is divided into pre-treatment and Post-treatment.The purpose of pre-treatment is to remove the surface oxide scale and greasy dirt, by that means increasing the adhesion of post-treatment and improving the appearance effect.The most commonly methods of pre-treatment are shot peening, sand blasting and phosphating. While Post-treatment generally uses spraying, oxidation, electroplating, electrophoresis. Other surface treatment methods only apply to products with special requirements for cost reasons.
From the cost point of view, the pre-treatment in turn are shot peening→sand blasting→phosphating→polishing, spray→ electrophoretic coating→oxidation→plating.After phosphating it can only be sprayed, electrophoresis, but can not be oxidized, electroplating.
In terms of decoration and anti-corrosion,the pre-treatment in turn are polishing→phosphating→sand blasting→shot blasting, oxidation→ plating→ spraying→electrophoretic coating.The shell of the automobile engine is generally treated by shot blasting and spraying.