ESCAによるチタン窒化層の測定

Abstract

Titanium surfaces nitrided in a N2 or NH3 stream and ion-nitrided in an atmosphere of N2 or a N2-H2 gas mixture were examined by ESCA. The following results were obtained. (1) The ESCA spectrum of Ti2p3⁄2 obtained from nitrided titanium was able to decovoluted into three peaks. A peak at a B.E. of 457.3 eV was interpreted as originating from TiNx (x>1), which was a hyperstoichiometric mononitride. The other peaks at 458.8 and 455.4 eV was identified as TiO2 and TiN, respectively. (2) As the N1s spectrum excited by Mg-Kα radiation exhibited two peaks, the existence of two kinds of titanium nitrides, that is, TiN and TiNx, is thought to be reasonable; the main peak at 397.2 eV seemed to be due to TiN and the minor one at 395.8 eV due to TiNx. (3) The dependence of ESCA peak intensities on the take-off angle of photo-electrons suggested that the nitrided titanium surface consisted of three layers; a topmost layer of TiO2, a midle layer of TiNx and an inner layer of TiN. (4) TiNx was readily formed when hydrogen was contained in the nitriding atmosphere. (5) The titanium nitrides were formed temperatures above 823 K by N2 gas-nitriding, and above 623 K by ion-nitriding. The formation of titanium nitride at low temperature by ion-nitriding seemed to suggest the essential difference in the nitriding process between gas and ion-nitriding.