Improvement in Oxidation Resistance of Cu-Al Dilute Alloys by Pre-annealing in H<SUB>2</SUB> and Ar Atmospheres

Abstract

The formation of protective Al2O3 thin layers on Cu-Al dilute alloys and their effect on the oxidation resistance has been investigated at high temperatures. Since selective and preferential oxidation of Al in Cu-Al alloys would take place under the very low oxygen pressures, Cu-Al (Al: 0.2∼2 mass%) alloys were annealed at various temperatures in H2 and/or Ar atmosphere. Continuous stable Al2O3 thin layers were formed on the specimens annealed in Ar after H2 annealing. Owing to the protective thin Al2O3 layers, the high temperature oxidation rates decreased to about 1/20 to 1/40 times lower than that of pure Cu.