Patent Number: 050930729
Section: description

EXAMPLE 1 Nature of the treated surface: stainless steel 316 L. Oxidizing pretreatment in the acid medium: Solution of KMnO.sub.4, whose molarity is 0.006 M. and HNO.sub.3, whose molarity is 0.035 M. Solution temperature: 80.degree. C. Treatment duration: 24 h. Rinsing with demineralized water: 1 h. Reducing treatment: Solution of sodium gluconate with a molarity of 1 M. and soda with a molarity of 0.25 M. Solution temperature: 80.degree. C. pH=11. Treatment time: 24 h. The erosion obtained is 1.28 .mu.m, i.e. 10 g/m.sup.2. EXAMPLE 2 Nature of the treated surface: stainless steel 316 L. Oxidizing pretreatment in acid medium: Solution and conditions identical to those of Example 1. Rinsing with demineralized water: 1 h. Reducing treatment: Solution of sodium gluconate with a molarity of 0.5 and soda with a molarity of 0.1 M. Solution temperature: 80.degree. C. pH=11. Duration of treatment: 24 h. Result: the erosion obtained is 0.05 .mu.m, i.e. 0.04 g/m.sup.2.