SmCo Magnets Technical Information

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SmCo Magnets (samarium cobalt magnets) permanent magnets are a family of rare earth magnets made from alloys of samarium and cobalt, hence the name. Unlike other types of rare earth magnets. SmCo Magnets (samarium cobalt magnets) are an excellent choice for applications where the magnet will be exposed to corrosion. By being more resistant to corrosion than their neodymium counterparts.

Mag Spring can make :

Biggest size :130x130x100mm
Smallest size:D1x1mm
Special Grade with Max working temperature 500℃
Highest Grade YXG-35H
Specail Magnets with magnetic deviation less than 1°

1Sintered SmCo Magnetic Properties
Max Dimension and Tolerance of Sintered SmCo Magnets
Mainly Coating of Sintered SmCo Magnets
Mechanical and physical properties of sintered SmCo Magnets
The process for Sintered SmCo Magnets
SmCo5 and SmCo17
1. SmCo5 magnets feature
2. Sm2Co17 magnets feature
How to Buy Samarium Cobalt Magnets?

1. Sintered SmCo Magnetic Properties

1.1 Sintered SmCo Magnetic Properties list :

Material	Grade	Br		Hcb		Hcj		(BH)max		Tc	Tw	α（Br）	β（Hcj)
		T	KGs	KA/m	KOe	KA/m	KOe	KJ/m³	MGOe	℃	℃	－%/℃	－%/℃
SmCO5 Sm2Co17	XGS16L	0.81-0.85	8.1-8.5	517-669	6.5-8.4	636-955	8--12	111-127	14-16	800	250	0.02	0.2
	XGS18L	0.85-0.90	8.5-9.0	525-708	6.6-8.9	636-955	8--12	127-143	16-18	800	250	0.02	0.2
	XGS20L	0.90-0.94	9.0-9.4	533-732	6.7-9.2	636-955	8--12	143-159	18-20	800	250	0.02	0.2
	XGS22L	0.94-0.97	9.4-9.7	533-740	6.7-9.3	636-955	8--12	159-175	20-22	800	250	0.02	0.2
	XGS24L	0.97-1.02	9.7-10.2	541-756	6.8-9.5	636-955	8--12	175-191	22-24	800	250	0.03	0.2
	XGS26L	1.02-1.05	10.2-10.5	541-764	6.8-9.6	636-955	8--12	191-207	24-26	800	250	0.03	0.2
	XGS28L	1.05-1.08	10.5-10.8	541-780	6.8-9.8	636-955	8--12	207-223	26-28	800	250	0.035	0.2
	XGS30L	1.08-1.11	10.8-11.1	541-796	6.8-10.0	636-955	8--12	223-239	28-30	800	250	0.035	0.2
	XGS32L-A	1.11-1.13	11.1-11.3	549-804	6.9-10.1	636-955	8--12	239-246	30-31	800	250	0.035	0.22
	XGS32L-B	1.13-1.15	11.3-11.5	550-805	6.9-10.1	636-955	8--12	246-255	31-32	800	250	0.04	0.25
	XGS33L	1.15-1.17	11.5-11.7	558-815	7.0-10.2	636-955	8--12	246-262	31-33	800	250	0.045	0.25
	XGS16M	0.81-0.85	8.1-8.5	573-669	7.2-8.4	955-1433	12--18	111-127	14-16	800	300	0.02	0.2
	XGS18M	0.85-0.90	8.5-9.0	605-708	7.6-8.9	955-1433	12--18	127-143	16-18	800	300	0.02	0.2
	XGS20M	0.90-0.94	9.0-9.4	637-732	8.0-9.2	955-1433	12--18	143-159	18-20	800	300	0.02	0.2
	XGS22M	0.94-0.97	9.4-9.7	645-740	8.1-9.3	955-1433	12--18	159-175	20-22	800	300	0.02	0.2
	XGS24M	0.97-1.02	9.7-10.2	661-764	8.3-9.6	955-1433	12--18	175-191	22-24	800	300	0.03	0.2
	XGS26M	1.02-1.05	10.2-10.5	685-788	8.6-9.9	955-1433	12--18	191-207	24-26	800	300	0.03	0.2
	XGS28M	1.05-1.08	10.5-10.8	693-812	8.7-10.2	955-1433	12--18	207-223	26-28	800	300	0.035	0.2
	XGS30M	1.08-1.11	10.8-11.1	700-828	8.8-10.4	955-1433	12--18	223-239	28-30	800	300	0.035	0.2
	XGS32M-A	1.11-1.13	11.1-11.3	708-852	8.9-10.7	955-1433	12--18	239-246	30-31	800	300	0.035	0.22
	XGS32M-B	1.13-1.15	11.3-11.5	716-860	9.0-10.8	955-1433	12--18	246-255	31-32	800	300	0.04	0.25
	XGS33M	1.15-1.17	11.5-11.7	726-870	9.1-10.9	955-1433	12--18	246-262	31-33	800	300	0.045	0.25
	XGS14	0.74-0.81	7.4-8.1	540-609	7.0-7.9	0.07	0.07	96--111	12--14	800	300	0.02	0.2
	XGS16	0.81-0.85	8.1-8.5	597-669	7.5-8.4	≥1433	≥18	111-127	14-16	800	300	0.02	0.2
	XGS18	0.85-0.90	8.5-9.0	621-708	7.8-8.9	≥1433	≥18	127-143	16-18	800	300	0.02	0.2
	XGS20	0.90-0.94	9.0-9.4	653-732	8.2-9.2	≥1433	≥18	143-159	18-20	800	300	0.02	0.2
	XGS22	0.94-0.97	9.4-9.7	677-740	8.5-9.3	≥1433	≥18	159-175	20-22	800	300	0.02	0.2
	XGS24	0.97-1.02	9.7-10.2	693-772	8.7-9.7	≥1433	≥18	175-191	22-24	800	300	0.03	0.2
	XGS26	1.02-1.05	10.2-10.5	748-796	9.4-10.0	≥1433	≥18	191-207	24-26	800	300	0.03	0.2
	XGS28	1.05-1.08	10.5-10.8	756-820	9.5-10.3	≥1433	≥18	207-223	26-28	800	300	0.035	0.2
	XGS30	1.08-1.11	10.8-11.1	788-836	9.9-10.5	≥1433	≥18	223-239	28-30	800	300	0.035	0.2
	XGS32-A	1.11-1.13	11.1-11.3	812-860	10.2-10.8	≥1433	≥18	239-246	30-31	800	300	0.035	0.22
	XGS32-B	1.13-1.15	11.3-11.5	820-870	10.3-10.9	≥1433	≥18	246-255	31-32	800	300	0.04	0.25
	XGS33	1.15-1.17	11.5-11.7	830-880	10.4-11.0	≥1433	≥18	246-262	31-33	800	300	0.045	0.25
	XGS14H	0.74-0.81	7.4-8.1	557-629	7.0-7.9	≥1990	≥25	96--111	12--14	800	350	0.02	0.2
	XGS16H	0.81-0.85	8.1-8.5	605-669	7.6-8.4	≥1990	≥25	111-127	14-16	800	350	0.02	0.2
	XGS18H	0.85-0.90	8.5-9.0	629-708	7.9-8.9	≥1990	≥25	127-143	16-18	800	350	0.02	0.2
	XGS20H	0.90-0.94	9.0-9.4	661-732	8.3-9.2	≥1990	≥25	143-159	18-20	800	350	0.02	0.2
	XGS22H	0.94-0.97	9.4-9.7	685-740	8.6-9.3	≥1990	≥25	159-175	20-22	800	350	0.02	0.2
	XGS24H	0.97-1.02	9.7-10.2	700-772	8.8-9.7	≥1990	≥25	175-191	22-24	800	350	0.03	0.2
	XGS26H	1.02-1.05	10.2-10.5	756-796	9.5-10.0	≥1990	≥25	191-207	24-26	800	350	0.03	0.2
	XGS28H	1.05-1.08	10.5-10.8	764-820	9.6-10.3	≥1990	≥25	207-223	26-28	800	350	0.035	0.2
	XGS30H	1.08-1.11	10.8-11.1	796-836	10.0-10.5	≥1990	≥25	223-239	28-30	800	350	0.035	0.2
	XGS32H-A	1.11-1.13	11.1-11.3	820-860	10.3-10.8	≥1990	≥25	239-246	30-31	800	350	0.035	0.22
	XGS32H-B	1.13-1.15	11.3-11.5	830-880	10.4-11.0	≥1990	≥25	246-255	31-32	800	350	0.04	0.25
	XGS33H	1.15-1.17	11.5-11.7	840-890	10.5-11.1	≥1990	≥25	246-262	31-33	800	350	0.042	0.28

Sm2Co17-LT	XGS14LT	0.74-0.81	7.4-8.1	557-629	7.0-7.9	≥1592	≥20	96--111	12--14	840	350	Temp.	α（Br）
	XGS16LT	0.81-0.85	8.1-8.5	605-669	7.6-8.4	≥1592	≥20	111-127	14-16	840	350	-50--20℃	+0.005%/℃
	XGS18LT	0.85-0.90	8.5-9.0	629-708	7.9-8.9	≥1592	≥20	127-143	16-18	840	350	20--200℃	-0.008%/℃
	XGS20LT	0.90-0.94	9.0-9.4	661-732	8.3-9.2	≥1592	≥20	143-159	18-20	840	350	200-300℃	-0.011%/℃

There are many kinds of High temperature magnets , such as Alnico magnets have lowest reversible temperature coefficient and can work at temperature up to 600 Celsius degree, but its BHmax( can only up to about 10-12MGOe) is very smaller than Neodymium Magnets (its BHmax is from 30-54MGOe), they are mainly used in various instruments. Most SmCo magnets can working up 300 Celsius Degree and Special high super temperature smco magnets can working up to 550 celsius degree, but its magnetic energy product can only up to 26MGOe , or up to 32MGOe with max working temperature is 300 Celsius degree. They are more brittle than neodymium magnets.

1.2 Demag curve

Demagnetization curves of XGS33H with temperature from 20℃ to 300℃

1.3 Magnetic Properties of UHT high temperature magnets-SmCo magnets 22G on 20℃ , 300℃ and 500℃

Material	Grade	Br		Hcb		Hcj		(BH)max		Tc	Tw	Test Temp
		T	KGs	KA/m	KOe	KA/m	KOe	KJ/m³	MGOe	℃	℃	℃
Sm2Co17	22G	0.95-1.0	9.5-10	>=715.5	>=9	>=1988	>=25	175-183	22-23	800	500	20
		0.84-0.86	8.4-8.6	>=556.5	>=7	>=1194	>=15	127-143	16-18	800	500	300
		>=0.7	>=7000	>=469.6	>=5.9	>=517	>=6.5	>=96	>=12	800	500	500

Demagnetization curves of UHT high temperature magnets from 20 ℃ to 300℃

Demagnetization curves of UHT high temperature magnets on 500℃

2. Maximum Dimension and Tolerance of Sintered SmCo Magnets

2.1 Sintered SmCo Magnets Shape Type and its Max Dimension

Shape	Picture	Dimenion	Recommended	Maximum
Shape	Picture	Dimenion	Dimension/mm	Dimension/mm
Block		L	≤100	≤ 200
		L	≤100	≤ 200
		W	≤80	≤100


		T	≤50	≤120
		T	≤50	≤120
Cylinder		D	≤100	≤130


		T	≤50	≤100


Ring		D	≤100	≤120


		d	≤60	≤80



		T	≤50	≤60
Segment		L	≤80	≤100
		L	≤80	≤100
		W	≤60	≤100
		H	≤60	≤100
		H	≤60	≤100
		a	0-180°C

Note 1: the three sizes noted above, only one or two of the largest sizes can be produced. M is the magnetization direction. Above pictures shown only the introduction of conventional shape products, we can also produce various shapes of samarium cobalt products, welcome to inquire with drawings.

2. When the dimensions in multiple directions are large, our special bonding process can be used.

3. Because the samarium cobalt material is very brittle, the thickness of the product with a large outer diameter or a large square should not be too thin, and the wall of a large ring product should not be too thin. The specifics should be determined according to shapes and magnetization directions, etc.

2.2 General Tolerance for sintered SmCo Magnets in different process

2.3 Geometric Tolerance for sintered SmCo Magnets in different process

3. Mainly Coating of Sintered SmCo Magnets

Nickel, Zink or Epoxy are available to avoid easy chips happening during assembling;

4. Mechanical and physical properties of sintered SmCo Magnets

Item	Unit	SmCo5	Sm2Co17
Density	g/cm3	8.1-8.5	8.3-8.5
Curie Temperature	℃	700-750	800-850
Recoil Permeability		1.00-1.05	1.00-1.1
Vickers Hardness	Hv	450-500	500-600
Electrical Resistivity	Ω·cm	5-6×10-5	8-9×10-5
Compressive Strength	Mpa	420-680	700-830
Thermal Conductivity	W/m·k		12
Coefficient of Thermal Expansion(C ⊥)	10-6/℃	13	11
Coefficient of Thermal Expansion(C //)	10-6/℃	6	8
Saturation Field	kA/m	＞1600	＞3200

5.The Process for SmCo Magnets

Preparation of Raw Materials → Melting and Casting → Crushing → Jet Milling → Orienting and Pressing → Vacuum Sintering and Aging→ Magnetic Properties Inspection → Machining → Surface Treatment → Magnetizing →Inspection and Packing → Delivery.

6. SmCo5 and SmCo17 Magnet

Samarium cobalt magnets can be divided into two categories based on their composition: SmCo5 and Sm2Co17, which are the first and second generation rare earth permanent magnet materials.

6.1 SmCo5 magnets feature

1:5 Samarium Cobalt magnet, also known as SmCo5 magnet, is a magnetic material made from metal samarium, cobalt, or a partial replacement of samarium with metal praseodymium, in a certain proportion, through smelting, crushing, pressing, and sintering. The maximum magnetic energy range of each grade is between 16-25, with a maximum working temperature of 250°C. The maximum magnetic energy product is lower than that of 2:17 samarium cobalt magnets, but the mechanical properties and ductility are slightly better than those of Sm2Co17 magnets. It is relatively easy to machine, and the product is less brittle than Sm2Co17 magnets, making it suitable for processing into shapes and specifications that are difficult to machine with 2:17 samarium cobalt, such as thin disks, squares, rings, and various complex shapes. Additionally, the magnetization magnetic field of 1:5 samarium cobalt magnet can be smaller than that of 2:17 samarium cobalt magnet. Generally, a 40,000 gauss magnetic field is sufficient for saturation magnetization, while a Sm2Co17 high coercivity samarium cobalt magnet requires a magnetic field of 60,000 gauss or higher. The rare earth content in the formula of 1:5 samarium cobalt magnet is as high as nearly 40%, so the price is higher than that of 2:17 samarium cobalt magnet. Users can reasonably choose to use 1:5 or 2:17 samarium cobalt magnets according to their own usage conditions when designing.

6.2 Sm2Co17 magnets feature

2:17 Samarium Cobalt magnet, also known as Sm2Co17 magnet, is a magnetic material made from metal samarium, cobalt, copper, iron, and zirconium, in a certain proportion, through smelting, crushing, pressing, sintering, and aging. The maximum magnetic energy product range of each grade is between 20-35, with a maximum working temperature of 350°C. Due to its low temperature coefficient and good corrosion resistance, Sm2Co17 magnets have magnetic properties that exceed neodymium iron boron magnets at high temperatures, making them widely used in aerospace, military, high-temperature motors, automotive sensors, various magnetic drives, magnetic pumps, and microwave devices.2:17 samarium cobalt is very brittle and is not easily processed into complex shapes or very thin sheets and thin-walled rings. Additionally, due to its brittleness, 2:17 samarium cobalt is prone to small chips during product processing, handling, inspection, and magnetization processes. As long as it does not affect the magnetic performance or function, these chips should be considered acceptable. Because the composition contains iron, its corrosion resistance is slightly worse than that of SmCo5, and plating may be required in special environments. It is particularly important to note that users must handle with care during assembly to avoid attracting two magnets or magnetizing them to iron objects, which can cause the magnets to break or injure people. Sm2Co17 magnets are not easily saturated during magnetization. If users need to magnetize them themselves, they must understand the size of the magnetic field of the magnetization equipment and then choose the appropriate grade.

7. How to Buy Samarium Cobalt Magnets?

If you want to buy right Samarium Cobalt Magnets, Please tell us the following information if possible.

Any drawing or Shape,Dimension and tolerance ;
SmCo Magnet Grade or Detailed Magnetic properties;
Almost no need coating because its own materials is corrosion resistance. But Nickel , Zink or Epoxy are available to avoid easy chips happening during assembling;
Direction of magnetization of Samarium Cobalt Magnets, magnetized or not magnetized for shipment;
Other requirement if possible;
Quantity, delivery way (sea shipment or air shipment );
Any Seaport or airport nearby your company.