Liquid nitriding, liquid oxygen-nitriding, QPQ, and OPO surface treatment technologies are metal salt bath surface strengthening and modification techniques. Through more than two decades of scientific research and practice, these two technologies have been widely applied in industry, involving dozens of industries such as automobiles, motorcycles, locomotives, textile machinery, construction machinery, hydraulic machinery, electrical appliances, light industry machinery, chemical equipment, instruments and meters, cameras, gears, tools, and molds.

Liquid Nitriding: Involves diffusing nitrogen, carbon, sulfur, and other elements into the metal surface, significantly enhancing its hardness with a uniform diffusion layer, and providing mechanical parts with excellent wear resistance and fatigue strength. It also boasts advantages such as minimal deformation, non-toxicity, and energy efficiency. Liquid Oxygen Nitriding: Based on liquid nitriding, this process adds an oxidation step, resulting in a metal surface that, while maintaining high hardness and wear resistance, also boasts greatly improved corrosion resistance. The surface is a glossy black, and can withstand neutral salt spray testing for up to 96-960 hours.