Sherardizing (Thermal Diffusion)

Sherardizing (Thermal Diffusion) is a specialized zinc coating process often called Vapor Galvanizing.

Process: Steel parts are tumbled in a drum with zinc dust and sand, then heated to ~400°C. The zinc turns into vapor and diffuses into the steel surface.

Result: A uniform, matte-grey coating that follows the exact shape of the part. It is perfect for threaded bolts and screws because it doesn't clog the threads like hot dipping can.