Titanium, boron and titanium diboride deposition in alkali fluorochloride melts

Frédéric Lantelme , Abdeslam Barhoun , El Mamoune Zahidi , Jens H. von Barner
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引用次数: 7

Abstract

The mechanism of the electroreduction of K2TiF6 and KBF4 in fused KCl–NaCl–NaF was determined from transient electrochemical techniques at temperatures ranging from 650 to 800 °C. The reduction of titanium occurred in a two-step reaction Ti4+ + e→ Ti3+ and Ti3+ + 3e→ Ti similar to that obtained in all-fluoride melts. The deposition of boron is obtained from the reduction of boron at oxidation state III: B3+ + 3e→ B. Cyclic voltammetry showed that when KBF4 was introduced in the KCl–NaCl–NaF–K2TiF6 melt a new peak appeared corresponding to the reaction Ti3+ + 2B3+ + 9e→ TiB2. Analysis by numerical simulation of the transient curves was used to obtain accurate values of the reaction parameters: rate constants, coverage factors, diffusion coefficients and standard potentials. From these measurements the thermodynamic properties of the solutions are calculated. It is shown that the Gibbs energy of formation of TiB2 deduced from the present experiments is in good agreement with the values in the literature.

钛、硼和二硼化钛在氟氯化碱熔体中的沉积
在650 ~ 800℃的温度范围内,采用瞬态电化学技术研究了熔融KCl-NaCl-NaF中K2TiF6和KBF4的电还原机理。钛的还原过程为Ti4+ + e−→Ti3+和Ti3+ + 3e−→Ti两步反应,与全氟熔体的还原过程类似。循环伏安法表明,在KCl-NaCl-NaF-K2TiF6熔体中加入KBF4后,出现了Ti3+ + 2B3+ + 9e−→TiB2反应峰。通过对瞬态曲线的数值模拟分析,得到了反应参数速率常数、覆盖系数、扩散系数和标准电位的精确值。根据这些测量结果,计算了溶液的热力学性质。结果表明,由本实验推导出的TiB2的吉布斯生成能与文献值吻合较好。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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