An environmentally friendly and practical method for obtaining color on stainless steel by interference

The coloration of AISI-304 stainless steel in 5.0 mol L-1 H2SO4 was investigated at different temperatures by applying the triangular current scan method. Thickest films were obtained at 50 degrees C using the following experimental parameters: i(min) = -0.81 mA cm(-2), i(max) = 1.40 mA cm(-2), and tau = 2.5 s. The film thickness increased (< 100-270 nm) with electrolysis time (20-60 min). The predominant colors were gold, red, and blue. The method used was successfully applied for coloring stainless steel in an aqueous solution of H2SO4 only, avoiding the use of chromic acid. (c) 2005 The Electrochemical Society.