Effects of NaPO3 concentration in Na2WO4-WO3 system on pulse electro-deposition tungsten coating from oxide molten slat

Electro-deposition technique is an attractive and promising technique to fabricate tungsten armor-coatings. Metallic tungsten coatings were obtained by pulsed electro-deposition on CuCrZr alloy used as a heat sink material. In this study, the effects of NaPO3 concentration and temperature on the crystal structure and morphologies of the coatings were investigated by XRD and SEM. Metallic tungsten coating was successfully obtained as the NaPO3 concentration is 30 mol% at the temperature of 1073 K in air atmosphere. XRD results show that the deposited coatings have the metallic tungsten crystal with a body centered cubic (BCC) structure. (2 1 1) orientation was favored most likely for each sample obtained at different temperatures. The average grain size of tungsten coatings was varies in the region of 3-15 μm. And the addition of NaPO3 have an obviously influence on the decrease of tungsten's grain size.