Preparation of W Coatings by Electrodeposition via Na₂WO₄-WO₃-NaCl Molten Salt System in Air Atmosphere

Tungsten (W) coatings on a Cu-Cr-Zr alloy surface were obtained by pulsed current electrodeposition from Na₂WO₄-WO₃-NaCl molten salt at different temperatures and current densities in an air atmosphere. The microstructure of the coating was observed, and the coating density, porosity, and hardness were tested. The results revealed W coatings with a silver-white metallic luster electrodeposited on the surfaces of a Cu-Cr-Zr alloy substrate when the temperature decreased from 1173 to 1023 K. The grain size and thickness of the W coatings changed significantly with current density, but the density, porosity, and hardness of the coating were slightly influenced by current density. The addition of NaCl refined the size of the tungsten grains in the W coatings. Among them, the W coating sample electrodeposited under 1123 K and 30 mA/cm² current density had the best performance, with a relative density of 96.95%, a porosity of 1.11%, and a hardness of 502.4 HV.