Co_3(Al,W) Intermetallic Compound: From Soft to Hard Ferromagnets

摘要

Influence of tungsten content on the crystal structure and magnetic properties of Co_3(Al,W)-based alloys were investigated. The phase and chemical compositions were determined by energy dispersive X-ray analysis and by the transmission electron microscope. A vibrating sample magnetometer and the SQUID magnetometer were used for the magnetic studies. The Co_3(Al,W)-based alloys are found to be heat-resistant ferromagnetic composite materials that consist of cobalt solid solution matrix and Co_3(Al,W) intermetallic compound with cubic L1_2 structure. The size and shape of the Co_3(Al,W) intermetallic phase depend on tungsten content. Coercive force (H_c) of the Co_3(Al,W)-based alloys increases from 1 Oe to 500 Oe with the increase in tungsten content from 4.6 to 12.6, respectively, while saturation magnetization falls down from 86 to 12 emu/g. Stripe magnetic domain structure with the domain thickness of 5-7 μm is found in the alloy with 12.6 %W.