Electrodeposition of Tungsten from Molten KF–KCl–WO3 and CsF–CsCl–WO3. Issue 4 (7th April 2021)

• Record Type: Journal Article
• Authors: Nohira, Toshiyuki; Ide, Tatsuya; Meng, Xianduo; Norikawa, Yutaro; Yasuda, Kouji
• Is Part Of: Journal of the Electrochemical Society. Volume 168:Issue 4(2021)
• Publication Date: 2021-04-07
• Subjects: Electrodeposition -- Molten Salts - High Temperature Molten Salts -- X-ray diffraction -- Tungsten; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/1945-7111/abf266
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : Electrodeposition of W coatings in KF–KCl eutectic melts was investigated after adding 0.5–2.0 mol% of WO3 at 923 K. Cyclic voltammetry at a Ag electrode suggested that the electrodeposition of W from W(VI) ions proceeds from 1.65 V vs K + /K. Electrodeposition of the α -W phase was confirmed by X-ray diffractometry (XRD). The effects of current density and amount of WO3 on the morphology of W coatings were investigated by surface and cross-sectional scanning electron microscopy (SEM). The smoothest W coating with a thickness of ∼15 μ m was formed at 12.5 mA cm −2 and 2.0 mol% WO3 in KF–KCl eutectic melts. By increasing the charge density, a coating thickness of ∼30 μ m was attained; however, it significantly increased the surface roughness of the coating. The electrodeposition of W was also performed in CsF–CsCl eutectic melts at a lower temperature of 873 K to suppress the growth of crystal grains. XRD confirmed the existence of both α -W and β -W phases in the W coatings deposited in the CsF–CsCl eutectic melts. SEM analyses revealed the successful formation of dense and smooth W coatings with ∼30 μ m thickness in the CsF–CsCl eutectic melts.