Effect of pre-oxidation treatments on the structural, microstructural, and chemical properties of (Ni,Pt)Al systems

Abstract

The effect of isothermal pre-oxidation treatments on the \b{eta}-(Ni,Pt)Al + Ren\'e N5 system degradation is here reported. The oxidation treatments were carried out from 900 (mostly {\theta}-Al2O3 growing conditions) to 1200{\deg}C (mainly {\alpha}-Al2O3 growing conditions) for 5 h, under a purified Ar-stream with a fixed pO2= 1 x 10-5 atm. Results are discussed based on the correlation between the structural, microstructural and chemical properties of the \b{eta}-(Ni,Pt)Al BC showing that pre-oxidation parameters have an important effect on the multi-elemental counter diffusion phenomena along BC. For instance, a significant BC+IDZ thickness increase of 55% at 1200 {\deg}C was observed with respect to as-received sample just after 5 h of oxidation resulting in a severe BC degradation.