Crystallization mechanism of Co77B23 amorphous alloy

Crystallization behavior of Co77B23 alloy at increasing temperature has bee n studied using resistivity measurements and auger-electron spectroscopy. T he amorphous nature of the specimen ribbon was ascertained by X-ray diffrac tion analysis. The resistivity measurements showed a gradual increase of re sistivity with temperature, which at about 600 K showed an abrupt fall in i ts value due to the onset of crystallization. As the heating continued, mor e peaks at different temperatures were detected in the resistivity-temperat ure distribution curve. These were identified as belonging to other phase c hanges in the crystallized alloy. Anger-electron analysis has been made to investigate chemical composition changes during heating. The results show a decrease in boron content on surface layers, which points to an inward dif fusion of boron atoms, An excess of cobalt atoms is left on the surface, ma king the amorphous layers on the surface unstable, which leads to crystalli zation. (C) 2000 Academic Press.