Preparation of spherical Ti-6Al-4V powder by RF induction plasma spheroidization combined with spray granulation

Abstract

Spray granulation was used to control morphology and particle size of raw materials for spheroidization in this work. Effects of dispersant (PAA-NH4OH) addition, pH value and solid content on stability of slurry for granulation was investigated. Influence of solid content of the slurry and atomizer speed on spray granulation were also investigated. Furthermore, difference in spheroidization effect between Ti-6Al-4V powder spheroidized from the granulated powder and irregular powder was compared. Results show that zeta potential of the slurry can be controlled at -44 mV to by addition of dispersant when pH value is 9.3. Granulated powder prepared with 50 wt% solid content and 10,000 rpm atomizer speed was best for plasma spheroidization. Ti-6Al-4V powder spheroidized from the granulated powder has better properties than that spheroidized from irregular powder. Spheroidization ratio, flow properties and apparent density of the spheroidized Ti-6Al-4V powder from granulated powder are 98%, 35.4 g/50s and 3.2 g/cm3, respectively.