電沉積TiB2的陰極過程
(1. 上海工程技術(shù)大學(xué) 材料工程學(xué)院, 上海 201600；
2. 華東理工大學(xué) 資源與環(huán)境工程學(xué)院, 上海 200237)
摘 要: 采用循環(huán)伏安法研究了700 ℃時46.5LiF-11.5NaF-42KF（摩爾分?jǐn)?shù), %）熔鹽中Ti(Ⅳ)（c(K2TiF6)=0.2 mol/L）和B(Ⅲ)（c(KBF4)=0.4 mol/L）在鉑電極上的電化學(xué)還原機(jī)理, 計(jì)算了各還原步驟傳遞的電子數(shù)。 研究了LiF-NaF-KF-K2TiF6-KBF4（c(K2TiF4)=0.3 mol/L, c(KBF4)=0.3, 0.6, 0.9 mol/L）熔鹽中電化學(xué)合成TiB2的陰極過程機(jī)理。 結(jié)果表明: Ti(Ⅳ)的電化學(xué)還原為三步電荷傳遞反應(yīng), 且陰極過程近似可逆； B(Ⅲ)在鉑電極上的電化學(xué)反應(yīng)機(jī)理為簡單的三電子一步反應(yīng), 陰極過程近似可逆； Ti(Ⅳ)和B(Ⅲ)可在同一電位下發(fā)生共沉積并反應(yīng)生成TiB2。
關(guān)鍵字: 二硼化鈦； 電化學(xué)還原； 熔鹽
KBF4 molten salt
（1. School of Materials Engineering,
Shanghai University of Engineering Science, Shanghai 201600, China;
2. School of Resource and Environment Engineering,
East China University of Science and Technology, Shanghai 200237, China）
Abstract: The mechanism of the electrochemical reduction of Ti(Ⅳ) (c(K2TiF6)=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-K2TiF6-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 be achieved.
Key words: titanium diboride; electrochemical reduction; molten salt
