双稀土处理液对H62黄铜成膜耐蚀性能的影响

Effect of Double Rare Earth Salt Solution Treatment on Corrosion Resistance of H62 Copper Alloy

为了提高H62黄铜合金的表面性能,通过正交试验获得了最佳锅、钵双稀土处理液配方。利用硝酸点滴、中性盐雾试验评价了H62黄铜合金钝化膜的耐蚀性能,通过电子探针(EPMA)观测了其表面形态结构及元素分布,利用电化学方法表征了 H62黄铜表面钝化膜在3.5%NaCl溶液中的缓蚀行为,采用XRD对H62黄铜表面钝化膜的成分进行了检测。结果表明:H62黄铜合金由镉、钵双稀土处理液钝化成膜的主要成分为Cu2O,CeO2,La(OH)3,Ce(OH)4;致密的钝化膜耐硝酸点滴时间达到21.98s,在3.5%NaCl溶液自腐蚀电位增加,腐蚀电流降低,腐蚀速度明显降低,耐蚀性能增加,耐中性盐雾性能明显优于鋪单一稀土处理液。

In order to improve the surface properties of H62 copper alloys, the formula of double rare earth salt solution was obtained by orthogonal test. The corrosion resistance of H62 copper alloy was evaluated by nitric acid drop and neutral salt spray test, and the surface morphology and elemental analysis were observed by electron probe (EPMA). The corrosion inhibition behavior of the copper alloy specimens in 3.5% NaCl solution was characterized by electrochemical method, and the composition of the copper alloy surface conversion film was examined by X-ray diffractometer. Results showed that the main components of the film layer on the copper alloy treated by the double rare earth salts were Cu2O, CeO2, La(OH) 3 and Ce(0H)4. The passivation film was dense, and the time of the resistance to nitric acid reached 21.98 s. The double rare earth conversion coating improved the self-corrosion potential in 3.5% NaCl solution, and the corrosion current decreased and the corrosion rate consequently decreased significantly. Besides, the neutral salt spray resistance of the coating by the double rare earth treatment was significantly better than that of the coating treated by the single rare earth salt.