Method for directly growing nano-crystal chromium nitride film on steel products

The process of growing nanometer crystalline chromium nitride film directly on steel includes the first nitriding and the salt bath chromizing of the nitrided steel at 500-650 deg.c after being cooledto room temperature and surface washing. The salt bath fluid for salt bath chromizing has base salt comprising NaC l20-25 wt%,BaCl2 30-35 wt% and CaCl2 40-50 wt%; and effective components including Cr powder 10-20 wt% of the base salt, Fe powder 5-10 wt% of the base salt, CrCl3.6H2O 25-50 wt% of the base salt, and Si powder 5-10 wt% of the base salt. The process grows nanometer crystalline CrN film directly on steel, and the film has great base bonding force, effect of reducing friction, fast growing speed and high suitability of steel types.