Open AccessElectrodeposition of Tungsten from Molten KF–KCl–WO3 and CsF–CsCl–WO3
Author(s) -
Toshiyuki Nohira,
Tatsuya Ide,
Xianduo Meng,
Yutaro Norikawa,
Kouji Yasuda
Publication year - 2021
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/abf266
Subject(s) - eutectic system , materials science , scanning electron microscope , cyclic voltammetry , tungsten , analytical chemistry (journal) , coating , phase (matter) , electrode , ion , electrochemistry , chemical engineering , microstructure , metallurgy , chemistry , nanotechnology , composite material , chromatography , organic chemistry , engineering
Electrodeposition of W coatings in KF–KCl eutectic melts was investigated after adding 0.5–2.0 mol% of WO 3 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 WO 3 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% WO 3 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.