ALNICO MAGNETS

Permanent Alnico Magnets,Sintered Alnico Magnets,Cast Alnico Magnets

Alnico Magnets

AlNiCo is a term referring to a series of permanent magnet alloys which in addition to iron are composed primarily of aluminum (Al), nickel (Ni), and cobalt (Co). The development of alnico began in 1931 when T. Mishima in Japan discovered that an alloy of iron, nickel, and aluminum had a much higher coercivity than the best steel magnets of the time. The composition of alnico alloys is typically 8–12% Al, 15–26% Ni, 5–24% Co, up to 6% Cu, up to 1% Ti, and the balance is Fe.

Various Alnico grades with differing magnetic properties are achieved by modifying the chemistry and manufacturing process.  For example, specialized casting techniques are used to achieve the unique crystalline grain orientation found in the Alnico 5-7 grade.

Before the development of rare earth magnets in the 1970s, Alnico was the strongest type of permanent magnet. In many applications, Alnico has been replaced by other types of magnets. However, the temperature stability of Alnico magnets, and the fact that they can be used in very high temperatures, up to 500C, make them indispensable in certain applications.

Typical magnetic properties of Cast Alnico magnets:

Grade Br HcB Hcj (BH)max Br Hcj Max Temp MMPA
Equivalents
KGs mT kOe Ka/m kOe Ka/m MGOe Kj/m³ TK(Br)%/K TK(Hcj)%/K ºC
ISOTROPIC CAST ALNICO MAGNETS
LN10 6.5 650 0.48 38 0.5 40 1.25 10 -0.035 -0.025 450 ALNICO3
LNG12 7.5 750 0.56 45 0.58 46 1.5 12 -0.03 -0.02 450 ALNICO2
LNGT18 5.5 550 1.13 90 1.21 97 2.25 18 -0.025 0.01 550 ALNICO8
ANISOTROPIC CAST ALNICO MAGNETS
LNG34 11 1100 0.63 50 0.65 52 4.25 34 -0.02 0.01 525 ALNICO5
LNG37 11.8 1180 0.61 49 0.64 51 4.63 37 -0.02 0.01 525
LNG40 12 1200 0.63 50 0.65 52 5 40 -0.02 0.01 525
LNG44 12.5 1250 0.65 52 0.68 54 5.5 44 -0.02 0.01 525
LNGT34 11.5 1150 0.73 58 0.75 60 3.5 28 -0.02 0.03 525 ALNICO6
LNG52 13 1300 0.7 56 0.73 58 6.5 52 -0.02 0.03 525 ALNICO5DG
LNG60 13.5 1350 0.73 58 0.75 60 7.5 60 -0.02 0.03 525 ALNICO5-7
LNGT38 8 800 1.38 110 1.4 112 4.75 38 -0.025 0.01 550 ALNICO8
LNGT40 8.5 850 1.44 115 1.46 117 5 40 -0.025 0.01 550
LNGT44 9 900 1.44 115 1.46 117 5.5 44 -0.025 0.01 550
LNGT36J 7.2 720 1.88 150 1.9 152 4.5 36 -0.025 0.01 550 ALNICO8HC
LNGT60 10 1000 1.38 110 1.4 112 7.5 60 -0.025 0.01 550 ALNICO9

Typical magnetic properties of sintered Alnico magnets:

Grade US Standard Br Hcb (BH)max Tc Tw T.C.α(Br)
mT/Gs kA/m/Oe kJ/m3/MGOe ℃ ℃ %/℃
FLN8 S.ALNICO3 500/5000 40/500 8/1.00 760 450 -0.022
FLNG12 S.ALNICO2 700/7000 48/600 12/1.50 810 450 -0.014
FLNGT18 S.ALNICO7 600/6000 90/1130 18/2.20 860 450 -0.02
FLNG34 S.ALNICO5 1200/12000 48/600 34/4.25 890 450 -0.016
FLNGT28 S.ALNICO6 1050/10500 56/700 28/3.50 850 450 -0.02
FLNGT38 S.ALNICO8 800/8000 120/1500 38/4.75 850 450 -0.02
FLNGT42 S.ALNICO8 880/8800 120/1500 42/5.25 820 450 -0.02
FLNGT33J S.ALNICO8HC 700/7000 140/1750 33/4.13 850 450 -0.025

Manufacturing Process of Alnico Magnets:

Alnico magnets are manufactured either by casting or sintering. Alnico is produced by conventional foundry methods using resin bonded sand molds or powder metal manufacturing methods. Sintering Alnico is suitable for complex geometries.

Most Alnico produced is anisotropic meaning that the magnetic axle of the grains is oriented in one direction. The orientation is achieved by a heat treatment process after casting or sintering.  The process involves heating the casting or sintered part above its Curie Temperature and then cooling it at a controlled rate in the presence of a directionalized magnetic field. The final shaping of the Alnico materials is achieved by abrasive grinding and cutting where close tolerances are required.

Process Flow: Raw Material—–Mixing—Melting—–Heat Treatment—–Magnetic Testing—-Grinding—–Inspection—–Packing and Shipping

Applications of Alnico Magnets:

1) Inner magnetic voltmeter/ammeter, measuring instrument, avometer, flow meter.
2) Magnetic sensors, polarized relay, temperature, and pressure controller.
3) Buzzer of mobile phone, hearing aids, mini speaker
4) Lighter of the automobile, the odometer of automobile and motorcycle, permanent motor, adsorptive appliance
5) Widely applied in high stability field as aviation, space flight, and military technology
In addition, due to the good corrosion resistance characteristic, non-coating is needed for surface protection.

Surface Treatment of Alnico Magnets:

Alnico magnets are not prone to corrosion and can normally be used without any surface protection. In some applications, however, a smooth surface is preferred.. Sinoneo can provide customers with high-quality coatings and plating of Zinc, Tin, Nickle, Epoxy, etc.

During the process of coating and plating, Sinoneo attaches great importance to environmental protection, all coating meets the requirements of ROHS and RECH.

Coating Code Color Minimum
Local
Thickness		 Merge etching time Working temperature
Neutral salt
Spray test		 Humid heat test Pressure
Vessel test
Ni(Barrel plating) Ni Sliver 10 24 300 48 <200
Ni(rack plating) Ni Sliver 10 8 300 48
NiCuNi(barrel plating) NiCuNi Sliver 10 72 500 48
NiCuNi(rack plating) NiCuNi Sliver 10 48 500 48
Zinc White zinc Zn White Zinc 4 24 48 / <170
Color zinc CZn/Zn Color Zinc 6 48 48 /
Chemical plating Ni Ni Silver 12 96 500 48 <200
Electrophoresis epoxy Epoxy Black,grey 10 48-96 120 0-24 <130
Parylene Parylene Colorless and transparent 12.7-25.4 microns
Meet the MIL-I-46058C standard		 48 / / <130

To offer you our Alnico magnets price, please offer the following details:

Magnets grade.
Magnets size: As the drawing
Magnetism direction: Which direction to oriented The north pole and south pole
Magnets coating: Without Coating, Nickel, Zn, Black Epoxy, Ag, Au, etc.
Quantities: More mass order quantities.More Lower the prices.