FORMATION OF CHROMIUM-OXIDE ON 316L AUSTENITIC STAINLESS-STEEL

The new technology using electrochemical buffed 316L austenitic stainl ess steel was developed to form an oxide scale as a passivation film w hich consists of an outer surface that is a perfect chromium oxide (Cr 2O3) layer of several tens nanometers thickness, and an inner part tha t contains iron and nickel oxides. This technology first makes the sta inless steel surface feature a very fine grain structure and introduce s Cr to the stainless steel surface through grain-boundary diffusion. Then a weak oxidizing ambience or a strong reductive ambience is creat ed to perform oxidation to form a perfect Cr2O3 film. Growth behavior of Cr2O3 film was analyzed with x-ray photoelectron spectroscopy by va rying each parameter of moisture, concentration, temperature, and dura tion of thermal treatment in ambience. The corrosion resistance of thi s film showed an excellent characteristic compared with the convention al electropolished surface. This shows a possibility of its applicatio n to specialty gas handling in semiconductor device manufacturing. (C) 1996 American Vacuum Society.