Steel parts are immersed in an aqueous Zn phosphate bath to form a thin Zn phosphate film of fine crystals that is not readily soluble. The layers bond well with the subsurface.

Advantages:
The capillary type of layer formation acts as a good sponge for oils and lacquers and provides an ideal bonding surface for subsequent surface treatment. This improves the anti-friction properties, providing the part with good temporary protection against corrosion.

Areas of application (examples):

• Motor industry
• Mechanical engineering industry