Study on glow discharge plasma aluminizing on titanium alloy surface

The Ti-Al alloying diffusion layer was fabricated on the surface of titanium alloy (Ti6Al4V) by double glow discharge plasma alloying technique. The pure aluminum was selected as the source cathode and Ar as the working gas. The microhardness of the surface of the sample was tested by HMV-1T micro-sclerometer. The cross sectional microstructure and the phase structure of the Ti-Al alloying layer were analyzed by means of scanning electron microscopy (SEM) and X-ray diffraction (XRD). The corrosion resistance of the Ti-Al alloying layer was studied using the method of the polarization curve in the 0.5 mol/L H2SO4 and the 3.5% NaCl solution. The results showed that it was feasible to prepare a Ti-Al alloying layer of 20 μm thickness by the process at 950 °C for 5 h. The microhardness of the Ti-Al alloying layer was as high as 8100 MPa, which was much larger than that of the Ti6Al4V. The phases were mainly Ti3Al and TiAl in the Ti-Al alloying layer. It was found that the Ti-Al alloying layer had excellent corrosion resistance properties.