In order to improve the wear resistance and corrosion resistance of the plastic mold surface, appropriate surface treatment is often performed on it.
1. Chrome plating of plastic molds is the most widely used surface treatment method. The chromium plating layer has strong passivation ability in the atmosphere, can maintain metallic luster for a long time, and does not undergo chemical reactions in a variety of acidic media.
The hardness of the coating reaches 1000HV, so it has excellent wear resistance. The chromium plating layer also has high heat resistance, and its appearance and hardness do not change significantly when heated to 500°C in the air.
2. Nitriding has the advantages of low processing temperature (generally 550~570℃), minimal mold deformation and high hardness of the nitrided layer (up to 1000~1200HV), so it is also very suitable for surface treatment of plastic machining.
Steel types containing alloy elements such as chromium, molybdenum, aluminum, vanadium and titanium have better nitriding properties than carbon steel. Nitriding treatment when used as plastic molds can greatly improve the wear resistance.
Surface treatment methods suitable for plastic parts molds include: nitrocarburizing, electroless nickel plating, ion plating of titanium nitride, titanium carbide or titanium carbonitride, hard film or super hard film deposited by PVD and CVD methods, etc.