Oxidation behavior of platinum-aluminum alloys and the effect of Zr doping

The isothermal and cyclic oxidation behavior of PtAl and PtAl+Zr was studied followed by postoxidation microstructural and microchemical analyses. Their isothermal oxidation performance at 1200 degree sign C was similar to that of NiAl and NiAl+Zr. In short (1-h) cycles, the cyclic oxidation resistance of undoped PtAl was found to be substantially better than NiAl. However, with longer (100-h) cycles, little improvement in the metal consumption rate was observed relative to NiAl. The addition of Zr to PtAl significantly improved cyclic oxidation performance in both short- and long-cycle tests. Spatially resolved energy dispersive spectroscopy indicated Zr segregation to both the metal-oxide interface and Al{sub 2}O{sub 3} grain boundaries. (c) 1999 Materials Research Society.