An XPS study of titanium-chromium nitride (Ti,Cr)N nanopowder prepared by heat treatment in flowing nitrogen gas

The electrical wire explosion of Cr-coated Ti wires produced nanosized particles consisting of various phases such as β(Ti,Cr), α-Ti, TiCr ₂ and TiN. The particles were heat treated at 800°C - 1100°C in flowing N ₂ gas in an effort to synthesize a ternary nitride, (Ti,Cr)N. An X-ray diffraction study revealed that they transformed to a single-phase (Ti,Cr)N during heating at 1100°C for 1 h. An X-ray photoelectron spectroscopy (XPS) was used to examine the electronic configurations of Ti, Cr, and O after nitriding at various temperatures. After heating at 800°C, the metallic Cr 2p peak vanished in accord with the disappearance of the β(Ti,Cr) phase confirmed by XRD. The inspection of XPS spectra suggested that the electronic configuration of (Ti,Cr)N is identical to that of TiN. The metal to nitrogen ((Ti + Cr)/N) ratio decreased with the nitriding temperature becoming 1 after heating at 1100°C. XPS quantification revealed that the ternary nitride had the composition of (Ti _0.6 Cr _20.4)N.