SURFACE MODIFICATION OF STAINLESS STEELS

A process involves the continuous surface treatment of stainless steel coils with aqueous suspensions of rare earth oxide nano or micro particles or aqueous rare earth nitrate solutions of nano or micro particles. The surface treatment can be applied by roll coating, spraying or other conventional application techniques. The treated material in coil form is then heated in an annealing box using an open coil process whereby a wire is placed between coil laps to promote uniform atmosphere exposure. The atmosphere can be reducing or oxidizing and the times can vary from 1 hr to 100 hr. The atmosphere can also be wet (high dew point) or dry (low dew point). The surface treatment promotes a more uniform color to the subsequently developed oxide formed during anneal-type heat treatment. It also improves corrosion resistance of the processed stainless steel material. Materials treated in this manner are suitable for a variety of applications in the building systems, automotive and appliance markets.