引用本文:
邱德瑜, 尹承滨. 铝在KOH溶液中的惰化[J]. 应用化学,
1986, 3(5): 54-57.
Citation: Qiu Deyu, Yin Chengbin. THE PASSIVATION OF AI IN KOH SOLUTION[J]. Chinese Journal of Applied Chemistry, 1986, 3(5): 54-57.
Citation: Qiu Deyu, Yin Chengbin. THE PASSIVATION OF AI IN KOH SOLUTION[J]. Chinese Journal of Applied Chemistry, 1986, 3(5): 54-57.
铝在KOH溶液中的惰化
摘要:
用恒电流充电曲线法研究了CKOH、CAl以及电流密度对铝电极惰化的影响,得到i~τ=1/2之间符合如下的不稳定扩散方程:(i-iL)τ1/2=(1/2)nF(CAlS-CAl°)(DAlπ)1/2=k (1)曲线由不同斜率的两条直线组成,iL系铝腐蚀产生H2搅拌的影响。同时,还求得了几种KOH溶液中CAlS和DAl的值。实验结果表明:低电流密度区,惰化过程受Al(OH)4-扩散控制,由过饱和Al(OH)4-溶液中析出成相的Al(OH)3或Al2O3膜,引起电极惰化。高电流密度区,除扩散外,还可能由电化学反应直接形成表面惰化层。
English
THE PASSIVATION OF AI IN KOH SOLUTION
Abstract:
The influence of the concentration of KOH and Al(OH)4- and current density on the passivation of Al has been investigated using galvanostatic charging method. It was shown that the relation between i and τ=1/2 obeys the well known non-steady state diffusion equation (i-iL)τ=1/2=(1/2)nF(CAlS -CAl0)(D(Al)π)1/2=k (1) The i~τ-1/2 curve was composed of two straight lines with different slops and CAlS, DAl have been calculated from the results based on equation(1). The results indicate that when current density is low the passivation of Al electrode is controlled by the diffusion of Al(OH)4- ions from the surface into the solution and an anodic passivation film is formed as a result of the precipitation of Al(OH)3 or Al2O3 from the super-saturated Al(OH)4- solution near the electrode surface. At higher current densities, the formation of the anodic passivation film is caused by both electrochemical reaction and the diffussion-controlled precipitation.
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