Improvement in Oxidation Resistance of Cu-Al Dilute Alloys by Pre-annealing in H₂ 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.