Non-hydrogen Carbrization On The Surface Of Commercially Pure Titanium By The Equipotential Hollow-cathode Glow Discharge

Titanium and its alloy are developed in the middle of twentieth Century and they are the important structural metal materials. Because of its low density, high specific strength, corrosion resistance and good biocompatibility, they are used widely. But the surface hardness of titanium is low, leading to its poor wear resistance, and easy to adhesive wear, and easy in reducing acid corrosion. In order to make up for its shortcomings, the surface alloying of titanium is used to improve it.In this experiment, the surface modification of equipotential hollow cathode plasma glow discharge technology is applied on commercially pure titanium TA1, the graphite is the source material, and the graphite source on the design of the structure, the cover body are the double graphite covers, and the outer cover of the graphite cover is made by carbon steel, and the commercially pure titanium TA1 work piece is placed in the inner graphite cover, and the uniform distribution of needle graphite source in commercially pure titanium TA1 work piece, which has the advantages of graphite source structure design is lower than the commercially pure titanium TA1 phase transition temperature, the equipotential hollow cathode glow discharge plasma non-hydrogen carburizing, which can guarantee the efficiency of graphite sputtering source, as well as the carbon concentration around the work piece, and stable the carburizing atmosphere, eventually to improve the surface physical and chemical properties of the commercially pure titanium at the same time, and ensure no loss of mechanical properties of commercially pure titanium.This experiment has the working temperature are 700 ℃、750 ℃ and 800 ℃. The results shows that the 4.0~8.0 μm alloy layer is formed on the surface, which is consisted of TiC phase. The maximum microhardness of the samples is 1298 HV0.2 that is 5.43 times than the original sample.The static tensile test shows that the tensile strength of the samples has improved than the original sample titanium surface after equipotential hollow cathode glow discharge non-hydrogen carburizing, and the tensile strength can reach 496.95 MPa, which has increased nearly 35.6% than the original commercially pure titanium TA1 366.57 MPa, and the elongation is not much different with the original sample, but the reduction rate decreased slightly. The tribological properties and the corrosion resistance of samples in the NaCl, H2SO4 and HCl solution are analyzed by the friction and wear tester and the electrochemical workstation. The results show that the wear resistance of the samples are improved. In 3.5% NaCl solution, the corrosion rate of the individual sample is 2.35×10-4 mm/a, that just is 1/10 of commercially pure titanium substrate; and in 0.5 mol/L H2SO4 solution, the corrosion rate of the individual sample is 1.67×10-3 mm/a, that just is 1/20 of commercially pure titanium substrate; and in 0.5 mol/L HCl, the corrosion rate of the individual sample is 4.89×10-3 mm/a, that just is 1/20 of commercially pure titanium substrate.