Rare-earth surface engineering in China

摘要

It has long been a challenge to industry to accelerate various surface engineering processes, so as to reduce energy consumption and to improve the properties of the resultant surface/subsurface system.One of the most significant achievements lies in the development of rare-earth surface engineering technologies, which started in HIT of China in the early of 1980s.At that time, the thermochemical treatments with the RE addition were investigated.In the following many years, a number of advantages of this new technique have been ascribed to addition of RE.These researchers suggest that the RE elements could diffuse into a significant depth of steels during gas carburizing, gas carbonitriding, gas nitrocarburizing, and plasma nitriding.The incorporated RE elements can help interstitial species (such as carbon and nitrogen) diffuse into a significant depth of the steel and enhance mass transfer as well as kinetics, and then improve the microstructures and properties of the modified layers.