缓蚀剂阳极脱附现象的研究──Ⅲ．缓蚀剂阳极脱附机制

ANODIC DESORPTION OF INHIBITORS Ⅲ.MECHANISM OF INHIBITOR DESORPTION

用电化学方法研究了缓蚀剂发生阳极脱附的机制。实验中发现缓蚀剂复盖度在低于脱附电位时保持不变，达到脱附电位后迅速降低。脱附电位则随缓蚀剂抑制能力的增强、浓度增加和氯离子的存在而正移。然而，缓蚀剂层对阳极溶解的阻力在脱附电位之前就逐渐降低。依据这些结果提出离子化金属粒子对吸附层的冲击导致缓蚀剂发生阳极脱附，而大量缓蚀剂脱附则发生在达到脱附电位后、缓蚀剂再吸附修补吸附层速度低于脱附速度时。

he mechanism of inhibitor desorption from an anodically polarized electrode was studied on basis of electrochemical measurements. It was indicated that the inhibitor coverage on electrode surface remained unchanged in the range of applied potential lower than the desorption potential (Edes), and decreased rapidly as it reached the Edes. It was also showed that the inhibitor with stronger adsorbility possessed a relatively high desorption potential and that increasing inhibitor concentration and addition of chloride also resulted in a positive shift in Edes. The resistance of adsorbed layer to anodic dissolution, however,had begun to decrease gradually even before the potential reached the Edes. According to the analysis mentioned above, an assumption was proposed that the inhibitor desorption was caused by the lash of dissolving metal ions against the adsorbed inhibitor layer, and the large scale desorption occurred only after attainment of the desorption potential because the reabsorption rate of inhibitor for mending the inhibitor layer destroyed was lower than the desorption rate.