Electrodeposition of metallic molybdenum films in ZnCl2–NaCl–KCl–MoCl3 systems at 250 °C

Molybdenum metal film has been electrodeposited in ZnCl2–NaCl–KCl (0.60:0.20:0.20, in mole fraction) melt containing MoCl3 at 250 °C. In this melt, a dense film was obtained by potentiostatic electrolysis at 0.15 V versus Zn(II)/Zn for 3 h. However, the film had a thickness of smaller than 0.5 μm and was not adhesive. On the other hand, addition of 4 mol% of KF to the melt led to larger cathodic current in cyclic voltammogram, and gave a dense, adhesive and thicker metal film of ca. 3 μm thickness in the same electrolysis condition as above. The present process is promising as a new method for molybdenum coating at low temperatures.