Effect of cooling rate on the atomic and crystal structure of rapidly cooled Fe75Si15B10

The alloy Fe75Si15B10 was formed as ribbon by melt spinning and as powder by gas-water atomization and by spark erosion in dodecane and liquid argon. The 27 μm ribbon and 20–30 μm particles formed by spark erosion in dodecane were completely amorphous while the gas-water-atomized 20–30 μm particles and the particles spark eroded in liquid argon were about 50% and 80%–90% crystalline respectively. The cooling rate for the ribbon was 106 K s−1 and that for the 20–30 μm particles spark eroded in dodecane was in excess of 5 × 106 K s−1. The cooling rate of the particles spark eroded in liquid argon was about 5 × 105 K s−1; the cooling rate for the gas-water-atomized particles was therefore between 5 × 105 and 106 K s−1. It appears that Fe75Si15B10 is not an easy alloy to obtain in the amorphous form and that the difference between the cooling rate required to form completely crystalline material and that to form completely amorphous material is less than an order of magnitude.