An Experiment Adopting Rare-earth Thermal Diffusion Penetration Technology To Improve The Comprehensive Performance Of Plastic Injection Mould Cavity Surface

Injection mould is the important process equipment of plastic products production, cavity surface often losses working precision because of some factors such as corrosion, wear, oxidation, fatigue, which lowers the service life of the injection mould and increases the cost of mould repair. Surface engineering technology could effectively improve the comprehensive performance of the mould cavity surface, wherein, the mechanical properties of the mould cavity surface will be enhanced by carburizing process, and then its wear resistance performance will be further enhanced after quenching process; Nitriding process could improve the micro-hardness, but the process cycle is too long, and nitrided layer is unstable; Carbonitriding process could not only improve the mechanical properties of the injection mould cavity surface, but also could improve the comprehensive performance; Carbonitriding process adopting rare earth elements accelerative penetration could substantially improve various aspects performance of the injection mould cavity surface.Lanthanum chlorinated is chosen as the rare earth additive in the article, dissolve lanthanum chlorinated in ethanol and confect permeability agent of different concentrations of rare earth. Choose the parameter which effects performance of the carbonitriding process layer by experiment. The most appropriate parameter is850℃of diffusion penetration temperature and4h of diffusion penetration time. Under the same experimental conditions, contrasting and analyzing the sample penetration layer adding on different concentration of rare earth, the best optimal addition amount of rare earth elements is between0.005g/ml and0.006g/ml.7The advantages of rare earth thermal diffusion penetration technology mainly include the effective accelerative diffusion permeability and increasing the penetration layer thickness, hardness, the amount of the carbon and nitrogen, making the hardness gradient of penetration layer tend to flat, improving the comprehensive performance of the injection mould cavity surface remarkably such as wear resistance, high temperature resistance, corrosion resistance, high-temperature oxidation resistance, effectively improving the service life of injection mould thereby.Rare earth elements accelerative diffusion carbonitriding process is increasingly mature, but its applications in injection mould cavity surface treatment are just beginning. The penetration mechanism of rare earth elements is analyzed in the article through the research of the rare earth thermal diffusion penetration experiment on the injection mould cavity surface treatment, Explained the rare earth elements’ accelerative penetration and increasing the thickness of the penetration layer and many other effects, make some meaningful tries for the industrial production and application of the rare earth carbonitriding technologies.