AlNiCo (AlNiCo) is the earliest developed permanent magnet material, which is an alloy composed of aluminum, nickel, cobalt, iron and other trace metal elements. Alnico permanent magnet materials were successfully developed in the 1930s. According to different production processes, it is divided into sintered AlNiCo (Sintered AlNiCo) and cast AlNiCo (Cast AlNiCo). Compared with the casting process, the size of sintered products is limited, the dimensional tolerance of the blank produced by it is better than that of casting products, the magnetic properties are slightly lower than that of casting products, but the machining performance is better, and it is mainly widely used in the field of instruments and meters and sensors, etc.
The advantages of AlNiCo magnets are high remanence (up to 1.35T) and low temperature coefficient. When the temperature coefficient is -0.02%/℃, the maximum working temperature can reach about 520℃.
Compared with the casting process, the size of sintered products is limited, the dimensional tolerance of the blank produced by it is better than that of casting products, the magnetic properties are slightly lower than that of casting products, but the machining performance is better, and it is mainly widely used in the field of instruments and meters and sensors, etc.
Manufacturing process
Alnico magnets are produced by casting or sintering processes. Cast alnico is produced by conventional methods using resin bonded sand molds. Sintered alnico magnets are formed using powdered metal manufacturing methods. Sintering alnico is suitable for complex geometries.
Most alnico produced is anisotropic, meaning that the magnetic direction of the grains is oriented in one direction. Anisotropic alnico magnets are oriented by heating above a critical temperature and cooling in the presence of a magnetic field. Both isotropic and anisotropic alnico require proper heat treatment to develop optimal magnetic properties.
Alnico 5 and alnico 8, are anisotropic, with each having a preferred direction of magnetization, or orientation. Anisotropic alloys generally have greater magnetic capacity in a preferred orientation than isotropic types.
| MMPA | IEC | Chemical | Physical Properties | Thermal Properties | ||||||||||||||||||
| Class | Code | Composition | ||||||||||||||||||||
| Ref. | (Balance Iron | |||||||||||||||||||||
| for all alloys) | Density | Tensile | Transverse | HRC | Coefficient | Electrical | Reversible | Curie | Max | |||||||||||||
| Strength | Modulus of | of Thermal | Resistivity | Temp. | Temp | Service | ||||||||||||||||
| Rupture | Expansion | "Ohm-cm | Coefficient | Temp | ||||||||||||||||||
| 10−6 per °C | x 10-6" | % Change per °C | ||||||||||||||||||||
| Al | Ni | Co | Cu | Ti | lbs/in3 | g/cm3 | psi | Pa x 106 | psi | Pa x 106 | (at 20 °C) | Near | Near | Hear | °C | °F | °C | °F | ||||
| Br | Max. | Hc | ||||||||||||||||||||
| Energy | ||||||||||||||||||||||
| Prod. | ||||||||||||||||||||||
| ISOTROPIC CAST ALNICO | ||||||||||||||||||||||
| Alnico 1 | R1-0-1 | 12 | 21 | 5 | 3 | - | 0.249 | 6.9 | 4000 | 28 | 14000 | 97 | 45 | 12.6 | 75 | |||||||
| Alnico 2 | R1-0-4 | 10 | 19 | 13 | 3 | - | 0.256 | 7.1 | 3000 | 21 | 7000 | 48 | 45 | 12.4 | 65 | -0.03 | -0.02 | -0.02 | 810 | 1490 | 450 | 840 |
| Alnico 3 | R1-0-2 | 12 | 25 | - | 3 | - | 0.249 | 6.9 | 12000 | 83 | 23000 | 158 | 45 | 13 | 60 | |||||||
| ANISOTROPIC CAST ALNICO | ||||||||||||||||||||||
| Alnico 5 | R1-1-1 | 8 | 14 | 24 | 3 | - | 0.264 | 7.3 | 5400 | 37 | 10500 | 72 | 50 | 11.4 | 47 | -0.02 | -0.015 | 0.01 | 860 | 1580 | 525 | 975 |
| Alnico 5DG | R1-1-2 | 8 | 14 | 24 | 3 | - | 0.264 | 7.3 | 5200 | 36 | 9000 | 62 | 50 | 11.4 | 47 | |||||||
| Alnico 5-7 | R1-1-3 | 8 | 14 | 24 | 3 | - | 0.264 | 7.3 | 5000 | 34 | 8000 | 55 | 50 | 11.4 | 47 | |||||||
| Alnico 6 | R1-1-4 | 8 | 16 | 24 | 3 | 1 | 0.265 | 7.3 | 23000 | 158 | 45000 | 310 | 50 | 11.4 | 50 | -0.02 | -0.015 | 0.03 | 860 | 1580 | 525 | 975 |
| Alnico 8 | R1-1-5 | 7 | 15 | 35 | 4 | 5 | 0.262 | 7.3 | 10000 | 59 | 30000 | 207 | 55 | 11 | 53 | -0.025 | -0.01 | 0.01 | 860 | 1580 | 550 | 1020 |
| Alnico 8HC | R1-1-7 | 8 | 14 | 38 | 3 | 8 | 0.262 | 7.3 | 10000 | 59 | 30000 | 207 | 55 | 11 | 54 | -0.025 | -0.01 | 0.01 | 860 | 1580 | 550 | 1020 |
| Alnico 9 | R1-1-6 | 7 | 15 | 35 | 4 | 5 | 0.262 | 7.3 | 7000 | 48 | 8000 | 55 | 55 | 110 | 53 | -0.025 | -0.01 | 0.01 | 860 | 1580 | 550 | 1020 |
| ISOTROPIC SINTERED ALNICO | ||||||||||||||||||||||
| Alnico 2 | R1-0-4 | 10 | 19 | 13 | 3 | - | 0.246 | 6.8 | 65000 | 448 | 70000 | 483 | 45 | 123.4 | 68 | |||||||
| ANISOTROPIC SINTERED ALNICO | ||||||||||||||||||||||
| Alnico 5 | R1-1-10 | 8 | 14 | 24 | 3 | - | 0.25 | 6.9 | 50000 | 345 | 55000 | 379 | 45 | 11.3 | 50 | |||||||
| Alnico 6 | R1-1-11 | 8 | 15 | 24 | 3 | 1 | 0.25 | 6.9 | 55000 | 379 | 100000 | 689 | 45 | 11.4 | 54 | |||||||
| Alnico 8 | R1-1-12 | 7 | 15 | 35 | 4 | 5 | 0.252 | 7 | 50000 | 345 | 55000 | 379 | 45 | 11 | 54 | |||||||
| Alnico 8HC | R1-1-13 | 7 | 14 | 38 | 3 | 8 | 0.252 | 7 | 55000 | 379 | 45 | 11 | 54 | |||||||||
| Grades | Equivalent MMPA | Remanence Br | Coercive Force Hcb | Maximum Energy Product (BH)max | Density | Reversible Temp. Coefficient а(Br) | Reversible Temp. Coefficient а(Hc) | Curie Temp. TC | Working Temp. TW | Remark | |||
| mT | Gs | KA/m | Oe | KJ/m3 | MGOe | g/cm3 | %/oC | %/oC | oC | oC | |||
| LN10 | Alnico3 | 600 | 6000 | 40 | 500 | 10 | 1.2 | 6.9 | -0.03 | -0.02 | 810 | 450 | Isotropy |
| LNG13 | Alnico2 | 700 | 7000 | 48 | 600 | 12.8 | 1.6 | 7.2 | -0.03 | 0.02 | 810 | 450 | |
| LNGT18 | Alnico8 | 580 | 5800 | 100 | 1250 | 18 | 2.2 | 7.3 | -0.025 | 0.02 | 860 | 550 | |
| LNG37 | Alnico5 | 1200 | 12000 | 48 | 600 | 37 | 4.65 | 7.3 | -0.02 | 0.02 | 850 | 525 | Anisotropy |
| LNG40 | 1250 | 12500 | 48 | 600 | 40 | 5 | 7.3 | ||||||
| LNG44 | 1250 | 12500 | 52 | 650 | 44 | 5.5 | 7.3 | ||||||
| LNG52 | Alnico5DG | 1300 | 13000 | 56 | 700 | 52 | 6.5 | 7.3 | |||||
| LNG60 | Alnico5-7 | 1350 | 13500 | 59 | 740 | 60 | 7.5 | 7.3 | |||||
| LNGT28 | Alnico6 | 1000 | 10000 | 57.6 | 720 | 28 | 3.5 | 7.3 | -0.02 | 0.03 | 850 | 525 | |
| LNGT36J | Alnico8HC | 700 | 7000 | 140 | 1750 | 36 | 4.5 | 7.3 | -0.025 | 0.02 | 860 | 550 | |
| LNGT38 | Alnico8 | 800 | 8000 | 110 | 1380 | 38 | 4.75 | 7.3 | -0.025 | 0.02 | 860 | 550 | |
| LNGT40 | 820 | 8200 | 110 | 1380 | 40 | 5 | 7.3 | -0.025 | 860 | 550 | |||
| LNGT60 | Alnico9 | 950 | 9500 | 110 | 1380 | 60 | 7.5 | 7.3 | -0.025 | 0.02 | 860 | 550 | |
| LNGT72 | 1050 | 10500 | 112 | 1400 | 72 | 9 | 7.3 | -0.025 | 860 | 550 | |||
| Grades | Equivalent MMPA | Remanence Br | Coercive Force Hcj | Coercive Force Hcb | Maximum Energy Product(BH)max | Density | Reversible Temp. Coefficient α（Br） | Curie Temp. TC | Working Temp. TW | Remark | ||||
| mT | Gs | KA/m | Oe | KA/m | Oe | KJ/m3 | MGOe | g/cm3 | %/oC | oC | oC | |||
| SLN8 | Alnico3 | 520 | 5200 | 43 | 540 | 40 | 500 | 44783 | 1.0-1.25 | 6.8 | -0.02 | 760 | 450 | Isotropy |
| SLNG12 | Alnico2 | 700 | 7000 | 43 | 540 | 40 | 500 | 44909 | 1.5-1.75 | 7 | -0.014 | 810 | 450 | |
| SLNGT18 | Alnico8 | 600 | 6000 | 107 | 1350 | 95 | 1200 | 18-22 | 2.25-2.75 | 7.2 | -0.02 | 850 | 550 | |
| SLNGT28 | Alnico6 | 1000 | 10000 | 57 | 710 | 56 | 700 | 28-30 | 3.5-3.8 | 7.2 | -0.02 | 850 | 525 | Anisotropy |
| SLNG34 | Alnico5 | 1100 | 11000 | 51 | 640 | 50 | 630 | 34-38 | 3.5-4.15 | 7.2 | -0.016 | 890 | 525 | |
| SLNGT31 | Alnico8 | 780 | 7800 | 106 | 1130 | 104 | 1300 | 33-36 | 3.9-4.5 | 7.2 | -0.02 | 850 | 550 | |
| SLNGT38 | 800 | 8000 | 126 | 1580 | 123 | 1550 | 38-42 | 4.75-5.3 | 7.2 | -0.02 | 850 | 550 | ||
| SLNGT42 | 880 | 8800 | 122 | 1530 | 120 | 1500 | 42-48 | 5.3-6.0 | 7.25 | -0.02 | 850 | 550 | ||
| SLNGT38J | Alnico8HC | 730 | 7300 | 163 | 2050 | 151 | 1900 | 38-40 | 4.75-5.0 | 7.2 | -0.02 | 850 | 550 | |
Alnico Magnet Disc 
Alnico Magnet Block 
Alnico Magnet Arc 
Alnico Magnet Ring