Cast AlNiCo Magnets

AlNiCo magnets are usually manufactured by casting process at a temperature above 2100℃ using conventional casting equipment. AlNiCo alloys obtained by casting usually need heat treatment to further improve their coercivity. Cast AlNiCo magnets includes two types:isotropic and anisotropic, according to the direction of application of magnetic field in the heat treatment process. After heat treatment, if no magnetic field is applied to AlNiCo alloys during cooling, they can be classified as isotropic materials; on the contrary, if a magnetic field is applied to them during cooling, it will become anisotropic materials.

Cast AlNiCo magnets can be processed into different sizes and shapes and have good machinability. Among permanent magnet materials, cast AlNiCo magnets have the lowest remanence temperature coefficient and can operate at temperatures up to 550 degrees Celsius. Cast AlNiCo magnets have better performance and lower price than sintered AlNiCo, so most AlNiCo magnets are cast. The most common Alnico cast magnets are AlNiCo2, AlNiCo3, AlNiCo4, AlNiCo5, AlNiCo6, AlNiCo8 and AlNiCo9. They retain about 85% of their room temperature strength up to 550°C and completely demagnetize at about 850°C.

Magnetic Properties of Cast AlNiCo Magnets

Grade Remanence

Br

 Coercive force
Hcb		 Maximum energy product
(BH)max		 Temperature coefficient（Br） HIGHEST WORKING TEMPERATURE MMPA Grade
mT Gs kA/m Oe kJ/m3 MGOe %/℃ ℃
LN10 600 6000 40 500 10 1.2 -0.02 550 AlNiCo3
LNG12 700 7000 44 550 12 1.5 -0.02 550 AlNiCo2
LNG13 680 6800 48 600 13 1.63 -0.02 550
LNG18 900 9000 48 600 18 2.25 -0.02 550 AlNiCo4
LNG37 1200 12000 48 600 37 4.63 -0.02 550 AlNiCo5
LNG40 1250 12500 48 600 40 5 -0.02 550
LNG44 1250 12500 52 650 44 5.5 -0.02 550
LNG52 1300 13000 56 700 52 6.5 -0.02 550 AlNiCo5DG
LNG56 1300 13000 58 720 56 7 -0.02 550
LNG60 1330 13300 60 750 60 7.5 -0.02 550 AlNiCo5-7
LNGT18 580 5800 90 1130 18 2.25 -0.02 550 AlNiCo7
LNGT28 1000 10000 56 700 28 3.5 -0.02 550 AlNiCo6
LNGT30 1100 11000 56 700 30 3.75 -0.02 550 AlNiCo6
LNGT32 800 8000 100 1250 32 4 -0.02 550 AlNiCo8
LNGT38 800 8000 110 1380 38 4.75 -0.02 550
LNGT44 850 8500 120 1500 44 5.5 -0.02 550
LNGT48 900 9000 120 1500 48 6 -0.02 550
LNGT60 950 9500 110 1380 60 7.5 -0.02 550
LNGT72 1050 10500 112 1500 72 9 -0.02 550 AlNiCo9
LNGT88 1100 11000 115 1450 88 11 -0.02 550
LNGT96 1150 11500 118 1480 96 12 -0.02 550
LNGT36J 700 7000 140 1750 36 4.5 -0.02 550 AlNiCo8HC
LNGT48J 800 8000 145 1820 48 6 -0.02 550 AlNiCo8HC
LNGT52J 850 8500 140 1750 52 6.5 -0.02 550 AlNiCo8HC

Sintered AlNiCo Magnets

Sintered AlNiCo is made by pressing AlNiCo alloy powder into a certain shape and then sintering it. Sintered AlNiCo magnets have lower magnetic properties than cast AlNiCo, but better mechanical properties, and can be manufactured in a variety of sizes and shapes that cast AlNiCo cannot produce. The sintering process is very suitable for large-scale production, and sintered AlNiCo parts are structurally stronger than cast magnets, and relatively close tolerances can be achieved without grinding.

The surface magnetic field strength of AlNiCo magnets is not as strong as that of NdFeB magnets and SmCo magnets, but it is very stable over a wide temperature range and has a high magnetic flux density.

Magnetic Properties of Sintered AlNiCo Magnets

Grade Remanence
Br		 Coercive force

Hcb

 intrinsic coercive force
Hcj		 Maximum energy product
(BH)max
(BH)max		 HIGHEST WORKING TEMPERATURE
T kGs kA/m kOe kA/m kOe kJ/m3 MGOe ℃
AlNiCo10/5 0.60-0.63 6.0-6.3 48-52 0.60-0.65 52-56 0.65-0.7 8-10 1.00-1.25 ≤450
AlNiCo12/5 0.70-0.75 7.0-7.5 48-56 0.60-0.70 52-58 0.65-0.73 11-13 1.4-1.6 ≤450
AlNiCo14/8 0.55-0.60 5.5-6.0 75-91 0.95-1.15 80-95 1.0-1.2 14-16 1.75-2.0 ≤550
AlNiCo20/10 0.60-0.64 6.0-6.4 93-110 1.16-1.38 100-118 1.25-1.4 18-22.4 2.25-2.8 ≤550
AlNiCo28/6 1.0-1.12 10.0-11.2 56-64 0.7-0.8 58-66 0.73-0.83 28-32 3.5-4.0 ≤550
AlNiCo34/5 1.15-1.23 11.5-12.3 48-56 0.60-0.70 49-57 0.62-0.72 32-36 4.0-4.5 ≤550
AlNiCo37/5 1.19-1.27 11.9-12.7 48-56 0.60-0.70 49-57 0.62-0.72 36-38 4.4-4.8 ≤550
AlNiCo40/5 1.22-1.26 12.2-12.6 50-56 0.62-0.7 51-57 0.64-0.72 38-40 4.8-5.0 ≤550
AlNiCo40/10 0.95-1.0 9.5-10.0 100-110 1.25-1.38 104-114 1.3-1.43 40-44 5.0-5.5 ≤550
AlNiCo38/11 0.80-0.85 8.0-8.5 111-121 1.40-1.52 114-125 14.3-15.7 38-40 4.8-5.0 ≤550
AlNiCo36/15 0.70-0.75 7.0-7.5 140-160 1.75-2.0 154-174 1.93-2.18 36-45 4.5-5.6 ≤550
AlNiCo40/16 0.7-0.75 7.0-7.5 160-175 2.0-2.2 174-189 2.18-2.37 40-44 5.0-5.5 ≤550
AlNiCo40/12 0.83-0.90 8.3-9.0 120-132 1.50-1.65 124-136 1.57-1.71 40-44 5.0-5.5 ≤550
AlNiCo45/13 0.89-0.91 8.9-9.1 120-132 1.50-1.65 126-138 1.58-1.73 44-50 5.5-6.2 ≤550