Cl. Chu et al., OXIDATION BEHAVIOR OF EQUIATOMIC TINI ALLOY IN HIGH-TEMPERATURE AIR ENVIRONMENT, Materials science & engineering. A, Structural materials: properties, microstructure and processing, 216(1-2), 1996, pp. 193-200
The isothermal oxidation behavior of equiatomic TiNi shape memory allo
y in dry air from 550 to 1000 degrees C is studied with thermogravimet
ric analysis. The alloy's scale layer is further investigated by X-ray
diffraction (XRD), scanning electron microscopy (SEM) and electron pr
obe microanalyzer. Experimental results indicate that a multi-layered
scale is formed, consisting of an outer rutile layer, a porous interme
diate layer of mixture of TiO2 and Ni(Ti), and a thin inner TiNi3 laye
r. The intermediate layer, furthermore, exhibits a stripe-like lamella
r structure at the TiNi3 interface. The apparent activation energy of
TiNi alloy oxidation is 226 kJ/mol, and the oxidation rate follows a p
arabolic law. A schematic oxidation mechanism of TiNi alloy is propose
d to explain the observed results.