alloys based on the iron (Fe) —nickel (Ni) –aluminum (Al) system, which have strong magnetic properties. Technical alloys contain 20 -34 percent nickel and 11–18 percent aluminum. With increasing nickel and aluminum content within the indicated limits, the residual induction Br decreases, and the coercive force Hc increases. The maximal magnetic properties [Br=0.5–0.65 T (teslas), Hc = 36–48 kiloamperes per meter (kA/m); maximum magnetic energy (BH)max = 4,000–5,200 joules/m3] are found in alloys containing 27–30 percent nickel and 11–14 percent aluminum. The presence of impurities in alni alloys decreases their magnetic properties. The most detrimental impurity is carbon, the content of which should not exceed 0.03 percent. The magnetic properties of alni alloys may be improved by additional alloying with copper (up to 6 percent), cobalt (up to 12 percent), silicon (alnisi alloys), and titanium. Further improvement of the magnetic properties of alni alloys containing in excess of 12 percent cobalt is feasible by thermomagnetic treatment. Magnets made of alni alloys, in view of their great hardness and brittleness, are made by intricate-shape casting or by powder metallurgical processes; magnets with complex shapes, by electric spark machining. Alni-alloy magnets are widely utilized in radio receivers, acoustic equipment, electrical measuring instruments, regulator devices, magnetic separators, and so on.
REFERENCESLivshits, B. G., and V. S. L’vov. Vysokokoertsitivnye splavy na zhelezonikel’aliuminievoi osnove. Moscow, 1960.
Postoiannye magnity: Spravochnik. Moscow-Leningrad, 1963. (Translated from English.)
B. A. SAMARIN