Pilling-Bedworth ratio for oxidation of alloys

Based on the theory of Pilling-Bedworth ratio (PBR) for metals, PBR for oxi dation of alloys is suggested PBRAlloy = Volume of a mole of BxOy/Volume of x moles of B in alloy. Three Al2O3 forming alloys (Ni3Al, NiAl and NiAl3) were used as examples to calculate PBR with this method. The results showed significant discrepanci es compared with the PBR calculated with aluminium metal. Calculation with the traditional method gave the PBR value for oxidation of Al as 1.29; calc ulations with the modified method gave the PBR values for Ni3Al, NiAl and N iAl3 alloys as 1.71 similar to 1.88, 1.64 similar to 1.78, and 1.48 similar to 1.57, respectively.