The glass forming abilities and magnetic properties of Fe-Al-Ga-P-B-Si and Fe-Al-Ga-P-B-C alloys

An investigation of glass forming abilities and thermal properties of Fe76-xAl4P12GaxB4Si4 and Fe75-xAl5P11GaxB4C5 (where x = 0, 2, 5) soft magnetic alloys was carried out using melt-spun ribbons of various thicknesses and suction cast rods of various diameters. For the Si-containing alloys, the critical thickness of amorphous ribbon increased from 55 to 110 mum between x = 0 and 5. On the other hand, for the carbon containing alloys, increasing x from 0 to 5 resulted in a decrease in critical thickness of amorphous ribbon from 150 to 100 mum. These data allowed the critical diameter of glassy cylindrical samples D-c to be estimated for appropriate alloy compositions and these are compared with experimental observations for suction cast rods. The magnetic properties, including the hysteresis loops and coercivity H-i(c) were determined by dc inductive magnetometry. The results indicate surprisingly low values of H-i(c) even for partially crystalline samples. On the other hand, the hysteresis loop shapes suggest a relatively large value of magnetic anisotropy. The possible reason for this behaviour is discussed. (C) 2003 Elsevier B.V. All rights reserved.