KF-KCl熔体中电沉积TiB2镀层

在铝工业中TiB2是一种非常有前途的阴极内衬取代材料.本研究首先通过热力学分析验证了在Ti-B-C体系生成TiB2的可能性,然后在K2TiF6和KBF4作为活性物质的KF-KCl熔体中以石墨为基体通过直流电沉积(CCP)和周期断开电流电沉积(PIC)技术制备了TiB2镀层,并且研究了电流密度和电镀技术对镀层表面平整度、致密度和晶粒尺寸的影响.结果表明,当电流密度为0.8 A/cm2时,能够得到厚度均匀且和基体具有良好附着的TiB2镀层;和CCP相比,采用PIC技术制备的TiB2镀层表面平整度和致密度都得到明显改善,并且晶粒也更为细小.XRD分析表明镀层由相对纯净的TiB2组成,并且镀层择优取向均为(001)面,这和二维晶核理论的预测相吻合.

Preparation of TiB2 Coatings by Electroplating in KF-KCl Molten Salt

Titanium diboride (TiB2) appears to be a promising material for corrosion prevention in aluminium industries. This paper first predicted the possibility of TiB2 formation in Ti-B-C system, and then focused on the preparation of TiB2 coatings by electroplating on the graphite in fluoride-chloride electrolytes (KF-KCl) containing K2TiF6 and KBF4 as the electrochemically-active components. The effect of current density and electroplating techniques on the surface leveling, compaction and grain size of coatings was investigated. The results show thick, adherent and uniform TiB2 coatings are obtained when the current density is 0.8 A/cm2; compared with continuous current plating (CCP), the surface leveling and compaction of coatings deposited by periodically interrupted current (PIC) are remarkably improved, and the crystal grain is finer. XRD analysis indicats that the coatings are composed of relatively pure TiB2 and the preferred orientation of coatings is (001) plane under experimental conditions, which is in accordance with the prediction of the two-dimensional crystal nuclei theory.