LiF-NaF-KF-K_2TiF_6-KBF_4熔体中电沉积TiB_2的阴极过程

Cathode process of titanium diboride electrodeposition in LiF-NaF-KF-K_2TiF_6-KBF_4 molten salt

采用循环伏安法研究了700℃时46.5LiF-11.5NaF-42KF(摩尔分数,%)熔盐中Ti(Ⅳ)(c(K2TiF6)=0.2 mol/L)和B(Ⅲ)(c(KBF4)=0.4 mol/L)在铂电极上的电化学还原机理,计算了各还原步骤传递的电子数。研究了LiF-NaF-KF-K2TiF6-KBF4(c(K2TiF4)=0.3 mol/L,c(KBF4)=0.3,0.6,0.9 mol/L)熔盐中电化学合成TiB2的阴极过程机理。结果表明:Ti(Ⅳ)的电化学还原为三步电荷传递反应,且阴极过程近似可逆;B(Ⅲ)在铂电极上的电化学反应机理为简单的三电子一步反应,阴极过程近似可逆;Ti(Ⅳ)和B(Ⅲ)可在同一电位下发生共沉积并反应生成TiB2。

The mechanism of the electrochemical reduction of Ti （Ⅳ） （c （K2 TiF6 ）= 0. 2 mol/L） and B （Ⅲ） （c（KBF4） =0.4 mol/L） on the platinum electrode in 46.5LiF-11.5NaF-42KF （mole fraction, %） molten salt at 700 ℃ were investigated by means of the cyclic voltammetry technique. The cathode process of titanium diboride （TiB2） formation was also studied on the platinum electrode in the 46.5LiF-11.5NaF-42KF-Kz TiF6-KBF4 （c（K2TiF4 ）= 0. 3 mol/L, c（KBF4）=0.3, 0.6, 0.9 mol/L）molten salt at 700 ℃. It is found that the electrochemical reduction of Ti （Ⅳ） proceeds in three-step charge transfer, the cathodic process is quasi-reversible. The electrochemical reduction of B（ Ⅲ ） occurs in one-step charge transfer, the cathodic process is quasi-reversible. The electrolytic codeposition of Ti（ Ⅳ ） and B（ Ⅲ ） with the formation of TiB2 can he achieved.