PRODUCTION OF FLAKY TI-BASED AMORPHOUS POWDER BY A 2-STAGE QUENCHING TECHNIQUE AND ITS THERMAL-STABILITY

Amorphous Ti-based flaky powders about 2 mum thick were produced in a wide range of particle size from 25 to 150 mum using a two-stage quenc hing technique consisting of impact flattening supercooled liquid drop lets obtained by high-pressure Ar atomization. The flaky powder partic les have a smooth surface with a sharp edge and good metallic luster, and their corrosion resistance is much better than that of pure Ti met al 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 mel t-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 l iquid droplets.