Characterization of titanium particles treated with N2 plasma using a barrel-plasma-treatment system

Metallic titanium (Ti) particles treated with N2 plasma via the barrel-plasma-treatment system were thoroughly evaluated, to investigate changes in physical and chemical properties resulting from the treatment. The color of the Ti particles changed from gray to uniform brown upon plasma-treatment, indicating good surface uniformity. Depth profiling using X-ray photoelectron spectroscopy showed that the nitrogen implanted by plasma-treatment formed Ti-N bonds at or near the surface of the particles, resulting in the formation of a stoichiometric TiN layer. It was determined from cross-sectional transmission electron microscopy and nanobeam diffraction measurements that the resulting TiN layer had two different structures. Nanoindentation data showed that the surface of a treated sample was about five times harder than that of untreated particles.