Production of flaky Ti-based amorphous powder by a two-stage quenching technique and its thermal stability

Abstract

Amorphous Ti-based flaky powders about 2 μm thick were produced in a wide range of particle size from 25 to 150 μm using a two-stage quenching technique consisting of impact flattening supercooled liquid droplets obtained by high-pressure Ar atomization. The flaky powder particles have a smooth surface with a sharp edge and good metallic luster, and their corrosion resistance is much better than that of pure Ti metal and SUS 304. The aspect ratio is as large as 20–300. No appreciable difference in T g and T x is found between the flaky powder and melt-spun ribbon, while the heat of structural relaxation for the powder is 2.0–2.9 times as large as that for the ribbon. It is concluded that the flaky amorphous powder is produced at a much higher cooling rate than the ribbon because of the subsequent cooling of the supercooled liquid droplets.