Study on double-glow plasma niobium surface alloying of pure titanium

A niobium modified layer on a pure titanium surface was obtained by means of a double-glow plasma surface alloying technique. Microstructure and phases resident in the alloy layer were analyzed. The processing parameters and effects of cathode sputtering before the diffusion process were also studied. The results show that the surface niobium content in the modified layer is similar to that in the Ti–45Nb alloy, and decreases gradually from the surface into the underlying substrate. The oxidation behavior of the modified pure titanium at 900 °C was noticeably improved after the niobium alloying process. Characterization was performed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The oxidation mechanism is also discussed.