Surface Oxidation of TiNiSn (Half-Heusler) Alloy by Oxygen and Water Vapor.

TiNiSn-based half-Heusler semiconducting compounds have the highest potential as -type thermoelectric materials for the use at elevated temperatures. In order to use these compounds in a thermoelectric module, it is crucial to examine their behaviour at a working temperature (approximately 1000 K) under oxygen and a humid atmosphere. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were utilized to study the surface composition and oxidation of the TiNiSn alloy at elevated temperatures.