磷酸介质中钼酸盐对镁合金的缓蚀作用

采用失重法、自腐蚀电位法研究了钼酸钠对AZ61镁合金在磷酸介质中的缓蚀作用及温度的影响,并对相关腐蚀动力学数据进行了计算.结果表明:钼酸钠对镁合金在磷酸介质中的溶解有一定的抑制作用,在试验缓蚀剂浓度范围(0～0.10mol/L)内,缓蚀效率与缓蚀剂浓度之间很好地符合线性关系;缓蚀机理属于阴极型被膜缓蚀作用;镁合金在不含和含0.10mol/L钼酸钠的0.50mol/L磷酸介质中反应的表观活化能分别为1092 J/mol和2499 J/mol;升高温度不能提高钼酸钠的缓蚀效率,但却有助于其较快发挥缓蚀作用.

Inhibition of Molybdate Salt on Dissolution of Magnesium Alloys in Phosphoric Acid

Corrosion inhibition of AZ61 magnesium alloys in phosphoric acid solution by molybdate salt was studied with gravimetric and corrosion potential measurements. Results show that the dissolution of magnesium alloys in 0.50mol/L phosphoric acid is reduced by the addition of molybdate salt. The inhibition efficiency and the concentration of inhibitor follow linear function within the experimental concentration range. The molybdate salt mainly inhibits the cathodic reactions of magnesium alloy through forming a passive layer and covering the cathodic active sites. The apparent activation energy for AZ61 magnesium alloys in 0.50mol/L phosphoric acid solution with and without 0.10 mol/L molybdate sah is respectively 2499 J/mol and 1092 J/mol. Increasing the temperature is not helpful to improve the inhibition efficiency while it can fasten the occurrence of inhibition.