Glossary

Phosphate and oil is a two-step finish applied to steel fasteners to improve corrosion resistance and reduce friction during installation. The process begins with a phosphate conversion coating, usually zinc or manganese phosphate, which creates a textured, matte surface. A light oil is then applied to enhance corrosion resistance and aid in handling.

Appearance - Phos & Oil fasteners typically have a dark gray to black matte finish with a slightly oily feel.

Zinc phosphate coating is a type of conversion coating applied to steel and iron fasteners to improve corrosion resistance, wear resistance, and paint adhesion. It is created through a chemical reaction in a phosphating solution, where zinc phosphate crystals form and bond tightly to the metal surface, creating a thin, matte, gray-to-black protective layer.

Unlike zinc plating, which deposits a layer of metallic zinc, zinc phosphate is a non-metallic crystalline coating that serves as a base for further treatments. It is often combined with oils, paints, or other topcoats to provide enhanced protection against rust. The microcrystalline structure also reduces friction, making it useful in fasteners where controlled torque and lubrication are important.