Overview of Alnico

Alnico describes a family of materials that possess excellent temperature stability, high residual induction, and relatively high energies. The alloy is derived from a common base composition comprised of aluminum, nickel, cobalt, and iron, with varying proportions of other elements.

Alnico alloys possess the lowest reversible temperature coefficient of any permanent magnet material. The high nickel content of alnico results in good resistance to corrosion and oxidation, and this material is also a good electrical conductor.

Manufacturing Differences

There are two different manufacturing processes for Alnico:

1. Cast alnico may be manufactured in many shapes and sizes not possible with other magnet materials.
2. Sintered alnico is usually restricted to smaller sizes and offers slightly lower magnetic properties, but has tighter dimensional tolerances due to its processing.

Advantages

• Wide range of working temperatures, up to 550C
• High field strengths
• Good corrosion resistance
• Can be plated or painted

Disadvantages

• Alnico can easily be demagnetized due its low coercive force.
• Alnico is hard, brittle and unsuited to common drilling, tapping or machining operations.

AMI#	Grade	Shape	OD	Length	Width	Thickness
M-10000	5	Rod	.187	1.187*
M-10200	5	Rod	.250	1.00*
M-10203	5	Rod	.197	1.181*
M-10206	5	Rod	.125	1.0*
M-10212	5	Rod	.375	1.5*
M-10213	5	Rod	.375	3.0*
M-10214	5	Rod	.500	3.0*
M-30000	5	Block		.875	.375	.125

*Indicates direction of orientation

Very small, precisely toleranced parts are available in sintered alnico in the range of .1"

Cast alnico allows for very large parts such as rods with diameters of 10" or more.