Electrochemistry of titanium in molten 2AlCl{sub 3}-NaCl
Electrochemistry of titanium in molten 2AlCl{sub 3}-NaCl
复制标题
钛在熔融2AlCl{sub 3}-NaCl中的电化学
DOI：
10.1149/1.2049976
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发表时间：
1995
影响因子：
3.9
通讯作者：
T. Moffat
中科院分区：
文献类型：
--
作者：
G. Stafford;T. Moffat
研究了钛在2AlCl{sub 3}-NaCl电解液中的电化学行为。钛可被氧化以产生Ti（II）、Ti（III）和Ti（IV）络合物。二价物质可用于电沉积铝-钛合金，而三价物质是微溶的。循环伏安法在钨电极上的溶液中具有不同的Ti（II）浓度已被用来检查与Ti（III）的沉淀反应的动力学。沉淀所需的诱导时间取决于Ti（II）的体相浓度，以类似于从水溶液中均匀沉淀所报道的方式。在较高的Ti（II）浓度和较慢的扫描速率下，电极被Ti（III）沉淀钝化。慢扫描速率伏安法表明钝化反应的i-E特性由与沉淀膜相关的电阻主导。该膜阻挡电极，防止Ti（II）氧化成Ti（IV）。钛金属的溶解动力学的平行研究揭示了由于Ti（III）沉淀的类似钝化现象。然而，钛上的钝化膜与钨电极上形成的沉淀膜不同，具有一定的导电性。这种区别可能是由于在沉淀膜和钛基体之间的界面处形成了致密的钝化膜。在更高的氧化电位下，钝化膜的保护性质随着Ti（IV）的产生而破坏。通过伏安法测定的Ti（II）浓度与从钛金属溶解中预期的Ti（II）浓度之间的比较揭示了在高Ti（II）浓度下偏离法拉第定律。这种差异是解决通过采用一个先前假设的模型，涉及形成低聚物的Ti（II）。从电池技术到铝基合金电镀的潜在应用正在探索中。«少
The electrochemistry of titanium has been examined in 2AlCl{sub 3}-NaCl electrolyte. Titanium may be oxidized to yield Ti(II), Ti(III), and Ti(IV) complexes. The divalent species may be used to electrodeposit al-Ti alloys, while the trivalent species is sparingly soluble. Cyclic voltammetry on a tungsten electrode in solutions with varying Ti(II) concentration has been used to examine the kinetics of the precipitation reaction associated with Ti(III). The induction time required for precipitation is dependent upon the bulk concentration of Ti(II), in a manner similar to that reported for homogeneous precipitation from aqueous solutions. At higher Ti(II) concentrations and slower sweep rats the electrode is passivated by the Ti(III) precipitation. Slow sweep rate voltammetry suggests that the i-E characteristics of the passivation reaction are dominated by the resistance associated with the precipitate film. The film blocks the electrode preventing oxidation of Ti(II) to Ti(IV). A parallel study of the dissolution kinetics of titanium metal reveals similar passivation phenomena due to Ti(III) precipitation. However, the passive film on titanium is somewhat conductive unlike that associated with the precipitated film formed on a tungsten electrode. This distinction presumably results from the formation of a compact passive film at the interface between the precipitated filmmore » and the titanium substrate. At more oxidizing potentials the protective nature of the passive film breaks down with the generation of Ti(IV). A comparison between the Ti(II) concentration determined by voltammetry and that anticipated from dissolution of titanium metal reveals a deviation from Faraday`s law at high Ti(II) concentrations. This discrepancy is resolved by adopting a previously postulated model involving the formation of oligomers of Ti(II). Potential applications ranging from battery technology to electroplating of aluminum-based alloys are being explored.« less