影响腐蚀的结构因素课件.ppt

1、123This is one of the most common forms of corrosion as well as one of the most destructive.Heres a classic example of galvanic corrosion;a stainless screw in contact with a cadmium plated steel washer.电偶腐蚀是最常见的腐蚀形式之一，也是最电偶腐蚀是最常见的腐蚀形式之一，也是最具破坏性的腐蚀之一。图为不锈钢螺丝与镀具破坏性的腐蚀之一。图为不锈钢螺丝与镀镉垫片接触，发生电偶腐蚀。镉垫片接触，发生电

2、偶腐蚀。4567Cathodic Reaction 1Anodic Reaction 2icorr 1+2Ecorr 1+2 E(V)log Current Density A/cm2Cathode Reaction 3Anode Reaction 3Total Cathode 1+3891011121314151617181920212223Brass bolt in a steel structureSteel bolt in a brass structureSmall brass cathode will cause small increase in corrosion of ste

3、el structure.Bolt will be protected from corrosion by coupling to steelSmall steel anode will suffer large increase in corrosion due to coupling with brass structure.24A milk cooler has an inner liner of stainless steel,and an outer casing of mild steel.Chilled brine（冷盐水冷盐水）is used between the steel and stainless steel to cool the milk.Corrosion of the mild steel is occurring-would it be a good idea to paint the inside of the mild steel casing?2526