Black Oxide Finishing Process Operates at Room Temperature

The Presto Black room-temperature black oxide metal finishing process from Birchwood Technology is designed for small- to medium-size production operations which require corrosion resistance and galling protection on critical surfaces for machine components. The process produces a non-dimensional coating thickness of less than 0.5 microns for components that require a black finish for visual appeal and rust protection. The 15-min. process is said to eliminate the hazards of the hot oxide process by operating at room temperature, about 70°F. The company says that it provides high corrosion resistance and is tested for 800 hrs. of humidity exposure when sealed with an appropriate rust preventive.

The finishing process provides a friable crystal structure that serves as a sacrificial barrier on sliding surfaces to protect the underlying steel itself from galling and deformation. The company recommends the coating for finishing hot rolled steels, alloy steels and tool steels as well as cast iron, forged steels and powdered metal. Birchwood’s Ion Exchange System enables the process to operate with zero discharge of rinse waters, cleaning and purifying them so they can be reused rather than sent to the drain.