Influence Of Nitrogen Ion Implantation At Elevated Temperature And Pretreatment Processes On Modified Surface Of Steel

The strengthened layer of ion implantation is too thin for the ion implantation to be widely applied. On basis of the study of nitrogen ion implantation at elevated temperature and metal ion implantation of the steel surface, the influence of pre-implantation of W, Mo, Cr, Cu, Ti, ultrasonic surface nanocrystalline modifacation on the surface modified layers is studied. And a hybrid surface modification technique composed of metal ion pre-implantation and nitrogen ion implantation at elevated temperature, which can greatly improve both the depth and hardness of the alloyed surface layer of ion implantation, was proposed. It is unveiled that:With the increase of the dose of nitrogen ion implantation at elevated temperature, the depth of the alloyed surface layer of the implanted 45 steel is increased while the friction coefficients and wear rates are reduced, but the influence of implantation dose on the peak of nitrogen content and surface hardness of the implanted 45 steel is unobvious. The peak of nitrogen content and surface hardness, the depth of the alloyed surface layer of implanted H13 steel increase with the increase of the dose of nitrogen ion implantation at elevated temperature, while the friction coefficients and wear rates of the implanted H13 steel samples are reduced. The inhomogeneous distribution of alloy element in M2 steel causes the non-uniform of the structure and properties of the implanted M2 surface treated by nitrogen ion implantation at elevated temperature, and the intermittent nitrogen ion implantation at elevated temperature can abate the unbeneficial effect of the inhomogeneous distribution of alloy element in M2 steel.W ion implantation can obviously improve the hardness of 45 steel; the friction coefficients of 45 steel sample can be reduced by ion implantation of W, Mo, Cr, Ti, and the improvement by Cr ion implantation is the best; the wear rate of 45 steel can be improved by ion implantation of Cr or W. The increase of ion energy is beneficial for the increase of the depth of the alloyed surface layer of the implanted samples, and the peak content of implanted element increase with increasing implantation dose.The diffusion of atoms during ion implantation at elevated temperature can be enhanced by Ti pre-implantation, Cr pre-implantation, and ultrasonic surface nanocrystalline modification, which increases the depth of the alloyed surface layer and reduces the gradient of the implanted element. The depth of the alloyed surface layer and the surface hardness of the implanted 45 steel can be increased by 110% and 50% respectively by Ti ion pre-implantation prior to the nitrogen ion implantation at elevated temperature. The depth of the alloyed surface layer and the surface hardness of the implanted 45 steel can be increased by 120% and 50% respectively by the application of ultrasonic surface nanocrystalline modification prior to nitrogen ion implantation at elevated temperature.