Common Characteristics of AlNiCo Magnets

AlNiCo permanent magnets are made up of alloys whose major constituents are iron, aluminum, nickel and cobalt, though other elements (e.g., copper and titanium) may be included in minor amounts.

Grades of AlNiCo vary in cobalt content, which ranges from zero (AlNiCo 3) to 40% (AlNiCo 8). Lower grades (2, 3 and 4) are unoriented in which magnetic properties are isotropic and equal in all directions.

Their magnetic output is relatively low. Anisotropic grades (SNT AlNiCo 5, 6, 8 and 9) are designed to produce high magnetic output in a specified direction. Orientation is achieved during heat treatment, by cooling the product from a temperature of about 2000°F (1093° C) at a controlled rate, within a magnetic field which conforms to the preferred direction of magnetization.

SNT AlNiCo 5, the most widely used grade, delivers energy to a magnetic circuit more economically than any of the other SNT Alnico grades. SNT Alnico 8 possesses the highest coercive force of all Alnico grades, as well as excellent energy per unit volume and a low reversible temperature coefficient. It is recommended for applications exposed to strong demagnetizing fields, or where space considerations dictate a short magnetic length.

SNT AlincoMAX88 and SNT AlincoMAX99 are premium grades of SNT Alnico 5 and 8, respectively. The superior magnetic output of these grades is produced by crystal orientation from the molten state in the desired direction of magnetization.