钛合金表面辉光离子渗铝耐蚀性

Study on Glow Discharge Plasma Aluminizing on Titanium Alloy Surface

利用双层辉光离子渗金属技术,在钛合金(Ti6Al4V)表面渗Al,形成均匀的钛铝合金扩散层。用显微硬度仪测量渗层的显微硬度,用SEM、XRD分析渗层的截面形貌和相结构,并在0.5mol/LH2SO4溶液和3.5%NaCl溶液中测试极化曲线方法。结果表明:经950℃,保温5h后Ti6Al4V合金基材表面形成厚度约为20μm的钛铝合金扩散层,扩散层由金属间化合物Ti3Al和TiAl组成;合金表面显微硬度值达到8100MPa;钛合金表面的耐蚀性能提高。

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 ℃ 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.