Design of molten salt bath reaction mechanism on the basis of acid-base cooperative smooth electrodeposition of tungsten from KF-B2O3-WO3 molten salt

This investigation was carried out to find a molten salt which enables a sm ooth electrodeposition of tungsten. The KF-B2O3-WO3 molten salt was selecte d on the basis of the acid-base cooperative reaction theory. A composition of KF(67 mol %)-B2O3(26 mol %)-WO3(7 mol %) was selected as the preferred b ath composition. Using a tungsten anode, smooth electrodeposits were obtain ed at 1123 K and at a current density ranging from 250 Am-2 to 550 Am-2 on nickel, copper, stainless steel, and mild steel substrates. When a graphite anode was used, smooth electrodeposits accompanied by dendrites were obtai ned. The Vickers microhardness number of the electrodeposit was 422 (load 0 .49 N). The smooth electrodeposit had tendencies to form the 111 fiber text ure or a mixed texture of the 111, 211 and 321 fiber textures.