作　　者： ; ;

机构地区： 华南师范大学化学与环境学院化学系

出　　处： 《中国腐蚀与防护学报》 2005年第1期25-29,共5页

摘　　要： 用线性电位扫描、循环伏安、计时电量及电位衰减等电化学方法 ,研究了铟在 3mol/LKOH溶液中的阳极钝化过程 铟在强碱性溶液中表现为一种活化—钝化金属 在活化区铟发生两步氧化 ,首先一电子氧化形成[InOH]ad,接着 [InOH]ad二电子氧化成 [In(OH) 3 ]ad,较低电位下前者较快后者较慢 ,表现为一电子反应 ;较高电位下两者均较快 ,表现为三电子反应 ,两者均受扩散步骤控制 单层 [In(OH ) 3 ]ad形成后使铟进入钝化区 [In(OH) 3 ]ad不稳定 ,在碱液中可以溶解和转变为In2 O3 在钝化区 ,铟直接氧化成三价铟 ,较高电位下形成稳定的In2 O3 ,较低电位下形成非化学计量的三价铟氧化物 ,其稳定性介于 [In(OH) 3 ]ad和In2 O3 The anodic passivation processes of indium in 3mol/L KOH solutions are investigated by using linear potential sweep,cyclic voltammetry,chronocoulometry and chronopotentiometry.Indium behaves as an active-passive metal in concentrated alkaline solution.The oxidation processes of indium proceed by two steps at active region,forming [InOH]_ ad from In and [In(OH)_3]_ ad from [InOH]_ ad .At lower potential,the formation of [InOH]_ ad is fast but the formation of [In(OH)_3]_ ad is slow,so the reaction behaves as one electron transfer.At higher potential,both formations of [InOH]_ ad and [In(OH)_3]_ ad are fast,so the reaction behaves as three electron transfer.Two kinds of the reactions at active region are controlled by mass transport step.With the formation of monolayer [In(OH)_3]_ ad,indium goes into the passive region.[In(OH)_3]_ ad is not stable.It can dissolve into the solution and be transformed into more stable In_2O_3.Indium is oxidized directly to trivalent indium at the passive region.Within the passive region,the oxidation product is stable In_2O_3 at higher potential,and nonstoichiometric In_2O_3 which is more stable than [In(OH)_3]_ ad but less than In_2O_3 at lower potential.

关 键 词： 铟 碱性溶液 阳极氧化 钝化

领　　域： [哲学宗教]