Thermal Stability and Oxidation Resistance of Pt–10 Al–4Cr Alloy at Super-High Temperatures

Abstract

The isothermal-oxidation behavior of refractory superalloy Pt-10Al-4Cr (in at.%) was investigated up to a period of 312 hr in air from 1200 to 1400°C. A comparison of the oxidation behavior of this alloy with a conventional Ni-base superalloy (Inconel 713C) shows an order of magnitude higher oxidation resistance. This experimental alloy oxidizes by forming Al 2 O 3 and Cr 2 O 3 (and perhaps trace amounts of PtO) with Al 2 O 3 as the oxide layer in contact with air. Optical and scanning-electron microscopy (SEM) were used to study the microstructure, morphology, and composition of the scale formed after oxidation. The thermal stability of the alloy after extended periods at 1200, 1300, and 1400°C was studied using transmission-electron microscopy (TEM).