Study On The Structure And Properties Of Titanium Surfaces By Double Glow Discharge Plasma Non-Hygrogen Carburizing

Titanium is used extensively in aerospace,chemical and hioengincering application because of many advantages such as high ratio of strength to toughness,light weight, excellent corrosion resistance, and biocompatibility . But titanium is restricted in application owing to its poor wear resistance and a tendency to galling . How to solve this question is the major concerns to potentials users.Numerous surface engineering technologies have been explored to enhance wear resistance of titanium and titanium while maintaining theirexcellent corrosion resistance and biocompatibility. Coating , plasmaimmersion ion implantation and plasma nitriding are amongst the technologies explored. Whereas the wear resistance of titanium and titanium alloy at low stresses and low velocities can be improved by the above techniques, cracking and debonding often occur at the modified layers at high sheer stresses. One of the solutions to the problem is increase the thickness of themodified layers to withstand the high shear stresses and (he risk of debonding .However thick modified layers are difficulty obtained using above technologies .Moreover increasing the thickness of the modified .layers may result in an increase in residual stress and risk of debonding .The thick, adhesive and wear resistant surface modified layer is obstained using an innovative plasma alloying technology .The improvement of material's tribological function is reflected by the main two aspects: first, reduce the material's friction coefficient; second, increase the wear resistance of material. Consider the graphite to have very excellent property of reducing friction. On the other hand, TiC exhibits high hardness and high tribological compatiblity. So if we had evolved a special penetrated layer which composed of the TiC and the dissociative C that we would provide titanium surfaces with improved tribological properties in terms of low friction and high resistance to wear. But now a major concern when using titanium as structural components is their compatility with hy -drogen. In carburizing technologies hydrogen can permeat titanium with carburizing and affect carburizing effect. It directly shows the material's plasticity and tenacity descend , intensity of materials greatly reduces ,and titanium surfaces shows crack,and so on. In order to solve this question non-hydrogen carburizing on titanium surfaces is studied in this paper by the Double-glow discharge plasma.Results show the carburizing layer of 50um was obstained .The carburizing layer is composed of the TiC and dissociative C. The microhardness of titanium surfaces attained 1000 (HV), the coefficient of friction declined to 0.25. The technology improves wear resistance of titanium.Moreover, passing the PS168 electricity chemical corrosion experiment, w> leaned that the corrosion resistance of titanium was also enhanced. Thi corrosion resistance of non-hydrogen carburizing layer was improved.Using the XRD,GDS,WS-92,M4()() phases and structure of carburizin{ layer were determined.