Preparation of highly preferred orientation TiB₂ coatings

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• 作者：Jun LI ; Bing LI ; Lushan JIANG ; Zheng'e DONG ; Yifu YE
• 关键词：coatings ; titanium diboride ; electrodeposition ; molten salt
• 刊名：Rare Metals
• 出版年：2006
• 出版时间：April 2006
• 年：2006
• 卷：25
• 期：2
• 页码：111-117
• 全文大小：964 K

文摘

This paper focuses on the preparation of titanium diboride (TiB₂) coatings on the graphite substrate by continuous current plating (CCP) and pulse current plating (PIC) electrochemical techniques in fluoride electrolytes (LiF-NaF-KF) containing K₂TiF₆ and KBF₄ as the electrochemically-active components at 700°C. Thick leveled and uniform coatings were obtained and were composed of relatively pure TiB₂. The effect of the experimental parameters on the microstructure of the coatings was studied. The results showed the electrodeposition with PIC produced coatings with better quality, when compared with those obtained by CCP, under the conditions of the current density i = 0.6 A/cm², frequency = 100 Hz, and t_on/t_off = 4/1. XRD analysis indicated that the preferred orientation of coatings is (110) plane, which is in accordance with the prediction of the two-dimensional crystal nuclei theory. The effect of a ratio of t_on/t_off and frequency on the crystal size, texture coefficient and microstress was also investigated.