Cast AlNiCo Magnets | SDM Magnetics

What Are Cast AlNiCo Magnets?

Cast AlNiCo magnets are non-rare earth metallic permanent magnets produced by pouring molten AlNiCo alloy into molds and then carrying out the required heat treatment and machining processes.

In comparison with sintered AlNiCo magnets, cast AlNiCo magnets are more widely used in practice and can generally provide higher overall magnetic performance.

Cast AlNiCo magnets are typically recognized by their dark grey or black rough-cast surface, while machined surfaces show a bright metallic finish.

Because of their combination of magnetic performance, temperature stability, and shape flexibility, cast AlNiCo magnets remain an important option for many demanding magnetic applications where reliable performance and adaptable geometry are both required.

Manufacturing Process of Cast AlNiCo Magnets

Cast AlNiCo magnets are manufactured by melting the alloy, pouring it into molds, and then carrying out a series of finishing steps such as cleaning, heat treatment, machining, magnetization, and packaging. Among these steps, heat treatment plays a particularly important role in developing the final magnetic properties of cast AlNiCo magnets.

Magnetic Properties of Cast AlNiCo Magnets

Cast AlNiCo magnets are available in a wide range of grades with different magnetic characteristics. In practical applications, the selection of grade is closely related to the required magnetic output, coercivity, operating temperature, and magnet design.

Grade of Cast AlNiCo Magnets

AlNiCo magnets are commonly identified by their MMPA grade names, such as AlNiCo 2, AlNiCo 3, AlNiCo 5, AlNiCo 5DG, AlNiCo 8, AlNiCo 8HC, and AlNiCo 9. In practical applications, these grades differ mainly in magnetic output, cobalt content, and coercivity.

Lower grades such as AlNiCo 2, AlNiCo 3, and AlNiCo 4 are unoriented and isotropic, so their magnetic output is relatively low. Anisotropic grades such as AlNiCo 5, AlNiCo 6, AlNiCo 8, and AlNiCo 9 are designed to provide higher magnetic output in a preferred direction and are more suitable for applications requiring stronger magnetic performance.

In China, cast AlNiCo magnets are also commonly designated by the LNG or LNGT naming system. These grade names are widely used in technical documents and magnetic property charts. The number that follows generally indicates the minimum value of the maximum energy product, while the letter J at the end indicates high coercivity.

If you are not sure which cast AlNiCo grade is suitable for your application, feel free to contact us for grade selection support.

Magnetic Properties Chart of Cast AlNiCo Magnets

Grade	Remanence Br		Coercivity Hcb		Max. Energy Product (BH)max		Temperature Coefficient ％/℃		Curie Temperature	Max. Operating Temperature	MMPA Standard
Grade	mT	Gs	kA/m	Oe	kJ/m³	MGOe	Br	Hcj	℃	℃	MMPA Standard
LN10	600	6000	40	500	10	1.20	-0.02	-0.03	810	450	AlNiCo3
LNG12	700	7000	44	550	12	1.50	-0.02	-0.03	810	450	AlNiCo2
LNG13	680	6800	48	600	13	1.63	-0.02	-0.03	810	450	AlNiCo2
LNG18	900	9000	48	600	18	2.25	-0.02	-0.03	850	450	AlNiCo4
LNG37	1200	12000	48	600	37	4.63	-0.02	-0.03	860	525	AlNiCo5
LNG40	1250	12500	48	600	40	5.00	-0.02	-0.03	860	525
LNG44	1250	12500	52	650	44	5.50	-0.02	-0.03	860	525
LNG52	1300	13000	56	700	52	6.50	-0.02	-0.03	860	525	AlNiCo5DG
LNG60	1330	13300	60	750	60	7.50	-0.02	-0.03	860	525	AlNiCo5-7
LNGT18	580	5800	90	1130	18	2.25	-0.02	-0.03	860	550	AlNiCo7
LNGT28	1000	10000	58	720	28	3.50	-0.02	-0.03	860	525	AlNiCo6
LNGT32	800	8000	100	1250	32	4.00	-0.02	-0.03	860	550	AlNiCo8
LNGT38	800	8000	110	1380	38	4.75	-0.02	-0.03	860	550
LNGT44	850	8500	120	1500	44	5.50	-0.02	-0.03	860	550
LNGT48	900	9000	120	1500	48	6.00	-0.02	-0.03	860	550
LNGT60	950	9500	110	1380	60	7.50	-0.02	-0.03	860	550
LNGT72	1050	10500	112	1400	72	9.00	-0.02	-0.03	860	550	AlNiCo9
LNGT88	1100	11000	115	1450	88	11.00	-0.02	-0.03	860	550	AlNiCo9
LNGT36J	700	7000	140	1750	36	4.50	-0.02	-0.03	860	550	AlNiCo8HC
The above-mentioned data of magnetic properties and physical properties are given at room temperature. The max working temperature of magnet is changeable due to length-diameter ratio, coating thickness and other environment factors.

How to Choose the Right Cast AlNiCo Magnet

Choosing the right cast AlNiCo magnet depends on several factors, including the required magnetic output, operating temperature, magnet shape, dimensional requirements, and magnet design. In many cases, both magnetic performance and resistance to demagnetization should be considered together during the selection process.

It is also important to determine whether an isotropic or anisotropic cast AlNiCo grade is more suitable for the application. Lower grades generally provide lower magnetic output, while anisotropic grades are intended to produce higher magnetic performance in a preferred direction. Surface finish, machining requirements, and assembly conditions may also affect the final choice.

If you need help selecting the right cast AlNiCo grade, shape, or machining route, feel free to contact us for technical support and product recommendations.