Abstract
The present authors previously discovered a high coercivity magnet alloy “Malcolloy” in the cobalt and aluminum system. They have ever since carried out investigations on the effect of the additions of nickel, molybdenum and titanium on its magnetic properties; the highest coercive force obtained is 1600 Oe. Further, they have investigated the effect of the addition of vanadium on the magnetic properties of Co-Al alloys and found that the addition of vanadium also increases the coercive force of the binary alloys. Thus, an alloy having the composition of 81.93% Co, 13.42% Al and 4.65% V shows a coercive force of 1450 Oe, a residual magnetic flux density of 3200 G and a maximum energy product of 1.40 MG·Oe, when tempered at 550°C for 15 hr after water-quenching from 1370°C. These alloys consist of many ferromagnetic elongated particles about 300∼400Å in diameter which are dispersed in the matrix of nearly nonmagnetic β′ phase. Consequently, it may be concluded that the high coercivity of these alloys is mainly caused by the existence of the small particles of the single magnetic domain.
