Alnico Rare Earth Magnets

Overview
Alnico magnetic material is an alloy of aluminum-nickel-cobalt which possesses an excellent temperature stability and high residual induction. However, its low coercive force limits its applications in many cases. Casting and sintering are two major processes used to manufacture the Alnico magnets.

Applications
Alnico magnets are usually used in motor, aerospace, military, communication devices, holding magnets, separators, sensors, security systems, MRI Relays Magnetos, etc.

Sintered Alnico - Typical Magnetic Performance Range, other standard

Grade	Residual Induction Br.		Coercive Force Hcb.		Intrinsic Coercive Force Hcj.		Max. Energy Product BH.		Density	Remark
	kGs	mT	kA/m	Oe	kA/m	Oe	KJ/m3	MGOe	g/cm3
FLN8	5.2	520	40	500	43	540	8-10	1-1.25	6.8	Isotropic
FLNG12	7.0	700	40	500	43	540	12-14	1.5-1.75	6.9
FLNG14	5.7	570	76	950	78	980	14-16	1.75-2.0	6.9
FLNG18	5.6	560	88	1100	90	1130	18-22	2.25-2.75	7.0
FLNG28	10.5	1050	46	580	47	590	28-33	3.5-4.15	7.3	Anisotropic
FLNG34	11.0	1100	48	600	50	630	33-38	4.1-4.7	7.3
FLNG35	12.2	1220	50	630	51	640	35-39	4.4-4.9	7.3
FLNGT28	10.0	1000	56	700	57	710	28-30	3.5-3.8	7.3
FLNGT31	7.8	780	104	1300	106	1130	33-36	3.9-4.5	7.3
FLNGT38	8.0	800	123	1550	126	1580	38-42	4.75-5.3	7.3
FLNGT42	8.8	880	120	1500	122	1530	42-44	5.3-5.5	7.3
FLNGT44	9.0	900	120	1500	125	1560	44-48	5.5-6.0	7.3
FLNG33J	6.5	650	136	1700	150	1880	31-36	4.1-4.5	7.3
FLNGT40J	8.0	800	1440	1800	155	1950	40-44	5.0-5.5	7.3
FLNGT44J	8.2	820	1520	1900	160	2000	44-48	5.5-6.0	7.3

More about Alnico Magnets

Alnico magnets, composed of primarily aluminum, nickel, and cobalt, were developed in the 1940's. This class of magnet remains a preferred material because of it's excellent temperature stability, high magnetic flux density, and resistance to corrosion. Alnico magnets are manufactured through a casting or sintering process. The casting process allows for the magnet to be manufactured into intricate and complex shapes, which are not possible with other magnetic materials.

Excellent temperature stability, high residual induction, and relatively high energies characterize Alnico materials, composed primarily of alloys of Aluminum, Nickel, and Cobalt. They are manufactured through either a casting or sintering process. Cast magnets may be manufactured in complex shapes, such as horseshoes, not possible with other magnet materials. Sintered Alnico offer slightly lower magnetic properties but better mechanical characteristics than cast Alnico. Cast Alnico 5 is the most commonly used of all the cast Alnico magnets. This material is used extensively in rotating machinery, meters, instruments, sensing devices, and holding applications, to name a few.

Alnico is hard and brittle. cannot be Machined or drilled. therefore be accomplished by ordinary methods. Holes are usually cored in at the foundry, and magnets are cast close to final size and then finish grinded to close tolerances.

Alnico has a low coercive force, and is easily demagnetized if not handled with care. For optimum performance of Alnico 5, the magnetic length should be approximately 5 times the pole diameter or equivalent diameter. For example, a 0.250" diameter magnet should be about 1.00" long.

Because of its higher coercivity, Alnico 8 may be used in shorter lengths and in disc shapes.