Electrodeposition of Tungsten from Molten KF-KCl-WO3 and CsF-CsCl-WO3

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 alpha-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 similar to 15 mu 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 similar to 30 mu 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 alpha-W and beta-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 similar to 30 mu m thickness in the CsF-CsCl eutectic melts.

Automated summary

The electrodeposition of W coatings in both KF-KCl eutectic melts and CsF-CsCl eutectic melts was studied. The effects of adding WO3 and changing the current density on the morphology and thickness of the W coatings were investigated, with XRD and SEM analysis confirming the successful formation of smooth and dense W coatings of different thicknesses. The experiments showed that different conditions led to the formation of W coatings with thicknesses ranging from approximately 15 to 30 μm.