Study on Particle Shape Control and Characterization of SUS316L Flake Powder Fabricated by Wet Milling Process

In this study, a particle shape control process was developed to fabricate flake-like SUS316L powders about 20 µm for application in semiconductor gas filters. The Flake powder was produced through a wet milling process using a Planetary Mill by varying the rotation speed, milling time, solvent, and polyvinylpyrrolidone (PVP) dispersant conditions. The fabricated powders were then characterized to evaluate their morphological and phase transformation behaviors. In the ethanol-based Planetary Milling process, as the rotation speed increased from 300, 400, 500 rpm, the powder morphology was observed to gradually change from spherical to flake-like due to the increase in milling energy. According to the XRD, as the rotation speed increased, a phase transformation from austenite to martensite occurred due to the increase in heat generation and collisions between the powder and balls. In addition, an increase in Full Width at Half Maximum (FWHM) was observed, indicating a decrease in crystallinity. Under different solvent and dispersant conditions, the addition of 5 wt% PVP to the deionized water (DI Water) solvent suppressed particle fracture and produced more uniform flake-like particles compared with the DI Water process without PVP. In addition, a smaller FWHM and reduced oxygen content were observed.