STEM-EELS identification of TiOXNY, TiN, Ti2N and O, N dissolution in the Ti2642S alloy oxidized in synthetic air at 650 °C

Oxide-alloy interface of Ti6242S Ti-based alloy was investigated by STEM-EELS technique, after oxidation in both N-2-free and synthetic air atmospheres at 650 degrees C for 1000 h. The chemical shift of Ti-L-2,L-3 edge and its specific fine structure along the oxide-alloy interface were used as fingerprint to distinguish the different compositions of titanium nitrides and oxynitrides. TiN, Ti2N and TiNXOY were identified in the sample oxidized in synthetic air at the oxide-alloy interface. Moreover, a decreasing in the oxidation state of Ti oxides was found along with Sn segregation at the oxide-alloy interface for the sample oxidized in N-2-free atmosphere.