The Hardness and Corrosion Properties of Trivalent Chromium Hard Chromium

Abstract

The formulation of hard chromium plating from trivalent chromium electrolyte and its related process have been intensively studied in this work. Through optimized conditions, the coating hardness can achieve more than HV0.1900 without any treatment and HV0.11700 after heat treatment for five minutes at 300°C, and the thickness of hard chromium coating was about 100 μm. The hard chromium coatings show good adhesion on the carbon steel and low alloy structural steel. The corrosion resistance of hard chromium coatings was enhanced by the adding nanometer materials into trivalent chromium plating coatings. More than 120 hours salt spray corrosion resistance can be achieved with 40 to 50 microns thickness of trivalent chromium plating coatings.