Patent ID: 7850791
Filing Date: 2010-12-14
Classification: C23C

Abstract:
1. A method for preparing a stable α-aluminum oxide protective layer for (i) an aluminum-containing alloy foil Fe—Al or Ni—Al having a thickness of 0.003 to 0.1 mm and an Al content of at least 8% by weight or for (ii) an aluminum-containing alloy foil Fe—Cr—Al or Ni—Cr—Al having a thickness of 0.003 to 0.1 mm and an Al content of at least 3% by weight, the method comprising the steps of: (a) depositing Ni, Fe, Cr or Ti on the surface of the aluminum-containing alloy foil (i) or (ii) in an oxygen atmosphere to form on the aluminum-containing alloy foil, an oxide layer of a non-aluminum-containing oxide having a thickness of up to 1000 nm effective to suppress formation of metastable forms of aluminum oxide; and (b) heating the aluminum-containing alloy foil (i) or (ii) on which is formed an oxide layer of a non-aluminum-containing oxide to a temperature of at least 800° C., whereby the oxide layer of the non-aluminum-containing oxide acts on the surface of the aluminum-containing alloy foil (i) or (ii) as a nucleating agent to promote formation of the stable α-aluminum oxide while suppressing formation of metastable forms of aluminum oxide.