Phosphating for Investment casting

Phosphating treatment is widely used pretreatment technology, a kind of chemical layer converting process. Such process are mainly used as the surface treatment for steel castings and iron castings. Sometime, they are also used for the ferrous metal castings, such as aluminium die castings or zinc castings.

Below are the processes for the phosphating treatment,

*Degrease preparation
*Degreasing
*Anti-rust protecting
*Water clearing
*Phosphating
*Water clearing
*Finish treatment, such as electrophoresis or powder coating

According to the tempurture control, thhere are several phosphating treatment types.

*High temperature phosphating
*Midium temperature phosphating
*Low temperature phosphating
*Normal temperature phosphating

Application for the phosphating treatment,

*Strength the binding force between the painting layer and the products.

*Increase the corrosion resistance of the casting surface

*Better the decorative surface of the casting

Several factors effect the phosphating treatment,

*Temperature
*Free acidity
*Total acidity
*PH value
*Ionic concentration
*Surface condition of the castings
*Water quality
*Preparation for phosphating