Patent ID: 6451130
Filing Date: 2002-09-17
Classification: C23C

Abstract:
A method for forming a chromium oxide film on a stainless steel surface, comprising:(a) placing a sample having a stainless steel surface into a vacuum furnace, evacuating the vacuum furnace to a pressure of 2Ã—10âˆ’7 to 3Ã—10âˆ’7 Torr, and heating the vacuum furnace to 450 to 600Â° C. at a rate of 5 to 10Â° C./min; (b) maintaining the pressure in the vacuum furnace for 10 to 20 minutes at a temperature of 450 to 600Â° C. to remove foreign materials from the surface of the stainless steel sample and to diffuse chromium atoms from the interior of the stainless steel; and (c) supplying oxygen to the vacuum furnace while maintaining the pressure and temperature until oxygen partial pressure reaches 1Ã—10âˆ’9 to 2.5Ã—10âˆ’7 Torr, so the chromium atoms diffused react with the oxygen, producing a chromium oxide (Cr2O3) film on the stainless steel surface.