Sintered NdFeB Magnet

Sintered NdFeB permanent magnet materials

Product overview

Known as “magnetic king”, Sintered NdFeB is the third generation rare earth permanent magnet material and the strongest permanent magnet material in the world with excellent magnetic properties widely used in automotive industry, industrial motors, consumer electronics, clean energy, aerospace and other fields; the main component of the magnet is Nd2Fe14B, which has extremely high magnetic properties.

Its BH max is more than 10 times higher than that of Ferrite, and the maximum working temperature can reach 250 ℃. Its mechanical properties are also quite good. It is suitable for grinding, wire cutting and drilling and other different processing methods; Due to its poor corrosion resistance, the surface must be coated with different coating processing (e.g. coating with Zn, Ni, Au, Epoxy, etc.) according to different requirements.

Production process

01 Alloy Melting

The main raw materials of sintered NdFeB permanent magnets are rare earth, iron and ferroboron, as well as cobalt, aluminum, copper, gallium, etc. The prepared raw materials are melted into alloy flakes under vacuum. Earth-Panda and REHT invested a joint venture factory to produce alloy flakes so as to ensure a stable supply of rare earth raw materials.

02 Hydrogen Decrepitation

Based on the hydrogen absorption and expansion principle of rare earth metals, alloy flakes are decrepitated into millimeter grade NdFeB coarse powder, which is stored in sealed containers for anti-oxidation. Earth-Panda has imported the continuous controlled atmosphere annealing furnace developed by Japan.

02

03 Jet Milling

Driven by high pressure gas, the NdFeB coarse powder collides with each other and decrepitates, and the particle size of the powder was refined to micron level to obtain the NdFeB fine powder. The fine powder is also stored in sealed containers for anti-oxidation.

04 Molding

Anisotropic NdFeB compacts are obtained by placing NdFeB fine powder into a mould under nitrogen atmosphere, then being oriented by electromagnetic field and under compression molding. By adjusting the shape and size of the mould, a variety of specifications of compacts can be obtained.

04

05 Sintering&Annealing

After vacuum sintering and aging, NdFeB compacts can improve physical properties such as density, strength, remanence and coercivity. Earth-Panda has imported several multi-chamber continuous vacuum sintering furnaces.

06 Machining

The sintered NdFeB compacts shall be machined into black sheet of various specifications and models. The machining methods mainly include: coreless grinding, double-side grinding, linear cutting, slicing, drilling, holing, tapping, etc. After machining, the specifications include: square, disc, circular ring, tile shape, special shape, etc

06

07 Grain Boundary Diffusion

Different types and quantities of substances are directly introduced into the grain boundary region of the magnets to react with the original grain boundary phase during sintering and subsequent aging process, so as to change the composition and structure of the grain boundary phase, and to further improve the properties of the magnets and reduce the addition amount of heavy rare earth in the magnets with high coercivity.

08 Coating

Surface Treatment is an important means to improve the surface protection capability of magnets. Earth-Panda has several full-automatic coating production lines to realize surface passivation, zinc plating, nickel plating, copper plating, electrophoretic epoxy, vacuum aluminum plating, zinc-aluminum spraying, etc. of magnets, meeting the requirements of different use environments of magnets.

08

09 Inspection

Earth-Panda can carry out many testing items such as magnetic performance, service characteristics and element analysis to provide reliable inspection guarantee and service for customers. The full-automatic inspection equipment makes the inspection efficiency improved rapidly and the inspection data more accurate. The analysis and testing center of the company has obtained the laboratory accreditation certificate issued by China National Accreditation Service for Conformity Assessment (CNAS), becoming one of the few CNAS accredited laboratories in the industry.

10 Magnetizing

Through the instantaneous pulse strong current in the coil, the coil produces an ultra-strong magnetic field, making NdFeB products magnetized. The magnetization direction can be divided into thickness magnetization, radial magnetization, multipole magnetization, etc.

10

11 Packing

Products are packed according to customer and company standards to suit the transportation requirements of cars, trains, ships and airplanes, and to safely deliver to customers.

Performance parameters

Traditional process
Special process
Other performances

	BrMagnetic properties								Temperature coefficient (typical)
Designation	Br		HcJ		HcB		(BH)max		Temperature range	(BH)max	(BH)max
Designation	T	kGs	kA/m	kOe	kA/m	kOe	kJ/m3	MGOe	℃	%/℃	%/℃
N35	1.18 ~ 1.24	1.18 ~ 1.24	≥ 955	≥ 12	≥ 860	≥ 10.8	263 ~ 295	33 ~ 37	20~80	﹣0.105	﹣0.75
N38	1.23 ~ 1.28	1.23 ~ 1.28	≥ 955	≥ 12	≥ 899	≥ 11.3	287 ~ 310	36 ~ 39
N40	1.26 ~ 1.31	12.6 ~ 13.1	≥ 955	≥ 12	≥ 915	≥ 11.5	302 ~ 326	38 ~ 41
N42	1.29 ~ 1.34	12.9 ~ 13.4	≥ 955	≥ 12	≥ 915	≥ 11.5	318 ~ 350	40 ~ 44
N45	1.33 ~ 1.38	13.3 ~ 13.8	≥ 955	≥ 12	≥ 915	≥ 11.5	342 ~ 366	43 ~ 46
N48	1.37 ~ 1.41	13.7 ~ 14.1	≥ 955	≥ 12	≥ 915	≥ 11.5	358 ~ 382	45 ~ 48
N50	1.39 ~ 1.43	13.9 ~ 14.3	≥ 955	≥ 12	≥ 915	≥ 11.5	374 ~ 398	47 ~ 50
N52	1.42 ~ 1.47	14.2 ~ 14.7	≥ 955	≥ 12	≥ 915	≥ 11.5	390 ~ 414	49 ~ 52
N54	1.45 ~ 1.50	14.5 ~ 15.0	≥ 876	≥ 11	≥ 836	≥ 10.5	406 ~ 430	51 ~ 54
35M	1.18 ~ 1.24	11.8 ~ 12.4	≥ 1114	≥ 14	≥ 868	≥ 10.9	263 ~ 295	33 ~ 37	20~100	﹣0.105	﹣0.70
38M	1.23 ~ 1.28	12.3 ~ 12.8	≥ 1114	≥ 14	≥ 907	≥ 11.4	287 ~ 310	36 ~ 39
40M	1.26 ~ 1.31	1.26 ~ 1.31	≥ 1114	≥ 14	≥ 931	≥ 11.7	302 ~ 326	38 ~ 41
42M	1.29 ~ 1.34	1.29 ~ 1.34	≥ 1114	≥ 14	≥ 955	≥ 12.0	318 ~ 350	40 ~ 44
45M	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1114	≥ 14	≥ 987	≥ 12.4	342 ~ 366	43 ~ 46
48M	1.37 ~ 1.41	1.37 ~ 1.41	≥ 1114	≥ 14	≥ 1019	≥ 12.8	358 ~ 382	45 ~ 48
50M	1.39 ~ 1.43	1.39 ~ 1.43	≥ 1114	≥ 14	≥ 1035	≥ 13.0	374 ~ 398	47 ~ 50
52M	1.42 ~ 1.47	1.42 ~ 1.47	≥ 1114	≥ 14	≥ 1059	≥ 13.3	390 ~ 414	49 ~ 52
35H	1.18 ~ 1.24	1.18 ~ 1.24	≥ 1353	≥ 17	≥ 876	≥ 11.0	263 ~ 295	33 ~ 37	20~120	﹣0.105	﹣0.60
38H	1.23 ~ 1.28	1.23 ~ 1.28	≥ 1353	≥ 17	≥ 915	≥ 11.5	287 ~ 310	36 ~ 39
40H	1.26 ~ 1.31	1.26 ~ 1.31	≥ 1353	≥ 17	≥ 939	≥ 11.8	302 ~ 326	38 ~ 41
42H	1.29 ~ 1.34	1.29 ~ 1.34	≥ 1353	≥ 17	≥ 963	≥ 12.1	318 ~ 350	40 ~ 44
45H	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1353	≥ 17	≥ 995	≥ 12.5	342 ~ 366	43 ~ 46
48H	1.37 ~ 1.41	13.7 ~ 14.1	≥ 1274	≥ 16	≥ 1027	≥ 12.9	358 ~ 382	45 ~ 48
50H	1.39 ~ 1.43	1.39 ~ 1.43	≥ 1274	≥ 16	≥ 1043	≥ 13.1	374 ~ 398	47 ~ 50
35SH	1.18 ~ 1.24	11.8 ~ 12.4	≥ 1592	≥ 20	≥ 884	≥ 11.1	263 ~ 295	33 ~ 37	20~150	﹣0.110	﹣0.55
38SH	1.23 ~ 1.28	1.23 ~ 1.28	≥ 1592	≥ 20	≥ 923	≥ 11.6	287 ~ 310	36 ~ 39
40SH	1.26 ~ 1.31	1.26 ~ 1.31	≥ 1592	≥ 20	≥ 947	≥ 11.9	302 ~ 326	38 ~ 41
42SH	1.29 ~ 1.34	1.29 ~ 1.34	≥ 1592	≥ 20	≥ 971	≥ 12.2	318 ~ 350	40 ~ 44
45SH	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1592	≥ 20	≥ 1003	≥ 12.6	342 ~ 366	43 ~ 46
48SH	1.37 ~ 1.41	1.37 ~ 1.41	≥ 1592	≥ 20	≥ 1035	≥ 13.0	358 ~ 382	45 ~ 48
30UH	1.08 ~ 1.15	10.8 ~ 11.5	≥ 1990	≥ 25	≥ 812	≥ 10.2	223 ~ 255	28 ~ 32	20~180	﹣0.110	﹣0.50
33UH	1.14 ~ 1.19	1.14 ~ 1.19	≥ 1990	≥ 25	≥ 860	≥ 10.8	247 ~ 271	31 ~ 34
35UH	1.18 ~ 1.24	1.18 ~ 1.24	≥ 1990	≥ 25	≥ 892	≥ 11.2	263 ~ 295	33 ~ 37
38UH	1.23 ~ 1.28	1.23 ~ 1.28	≥ 1990	≥ 25	≥ 931	≥ 11.7	287 ~ 310	36 ~ 39
40UH	1.26 ~ 1.31	1.26 ~ 1.31	≥ 1990	≥ 25	≥ 955	≥ 12.0	302 ~ 326	38 ~ 41
42UH	1.29 ~ 1.34	1.29 ~ 1.34	≥ 1990	≥ 25	≥ 979	≥ 12.3	318 ~ 350	40 ~ 44
45UH	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1990	≥ 25	≥ 1011	≥ 12.7	342 ~ 366	43 ~ 46
30EH	1.08 ~ 1.15	1.08 ~ 1.15	≥ 2388	≥ 30	≥ 820	≥ 10.3	223 ~ 255	28 ~ 32	20~200	﹣0.115	﹣0.45
33EH	1.14 ~ 1.19	1.14 ~ 1.19	≥ 2388	≥ 30	≥ 868	≥ 10.9	247 ~ 271	31 ~ 34
35EH	1.18 ~ 1.24	1.18 ~ 1.24	≥ 2388	≥ 30	≥ 899	≥ 11.3	263 ~ 295	33 ~ 37
38EH	1.22 ~ 1.26	1.22 ~ 1.26	≥ 2388	≥ 30	≥ 931	≥ 11.7	287 ~ 310	36 ~ 39
40EH	1.25 ~ 1.29	1.25 ~ 1.29	≥ 2388	≥ 30	≥ 955	≥ 12.0	302 ~ 326	38 ~ 41
30TH	1.08 ~ 1.15	1.08 ~ 1.15	≥ 2786	≥ 35	≥ 820	≥ 10.3	223 ~ 255	28 ~ 32	20~250	﹣0.115	﹣0.40
33TH	1.14 ~ 1.19	1.14 ~ 1.19	≥ 2786	≥ 35	≥ 868	≥ 10.9	247 ~ 271	31 ~ 34
35TH	1.18 ~ 1.24	1.18 ~ 1.24	≥ 2786	≥ 35	≥ 899	≥ 11.3	263 ~ 295	33 ~ 37
38TH	1.22 ~ 1.26	1.22 ~ 1.26	≥ 2786	≥ 35	≥ 931	≥ 11.7	287 ~ 310	36 ~ 39

The parameters tables are best viewed in desktop view

	BrMagnetic properties								Temperature coefficient (typical)
Designation	Br		HcJ		HcB		(BH)max		Temperature range	(BH)max	(BH)max
Designation	T	kGs	kA/m	kOe	kA/m	kOe	kJ/m3	MGOe	℃	%/℃	%/℃
52M	1.42 ~ 1.47	1.42 ~ 1.47	≥ 1114	≥ 14	≥ 1059	≥ 13.3	390 ~ 414	49 ~ 52	20~100	﹣0.105	﹣0.70
54M	1.45 ~ 1.50	1.45 ~ 1.50	≥ 1114	≥ 14	≥1075	≥ 13.5	406 ~ 430	51 ~ 54	20~100	﹣0.105	﹣0.70
45H	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1353	≥ 17	≥ 995	≥ 12.5	342 ~ 366	43 ~ 46	20~120	﹣0.105	﹣0.60
48H	1.37 ~ 1.41	1.37 ~ 1.41	≥ 1274	≥ 16	≥ 1027	≥ 12.9	358 ~ 382	45 ~ 48
50H	1.39 ~ 1.43	1.39 ~ 1.43	≥ 1274	≥ 16	≥ 1043	≥ 13.1	374 ~ 398	47 ~ 50
52H	1.42 ~ 1.47	1.42 ~ 1.47	≥ 1274	≥ 16	≥ 1067	≥ 13.4	390 ~ 414	49 ~ 52
45SH	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1592	≥ 20	≥ 1003	≥ 12.6	342 ~ 366	43 ~ 46	20~150	﹣0.110	﹣0.55
48SH	1.37 ~ 1.41	13.7 ~ 14.1	≥ 1592	≥ 20	≥ 1035	≥ 13.0	358 ~ 382	45 ~ 48
50SH	1.39 ~ 1.43	13.9 ~ 14.3	≥ 1592	≥ 20	≥ 1051	≥ 13.2	374 ~ 398	47 ~ 50
52SH	1.42 ~ 1.47	1.42 ~ 1.47	≥ 1592	≥ 20	≥ 1075	≥ 13.5	390 ~ 414	49 ~ 52
40UH	1.26 ~ 1.31	1.26 ~ 1.31	≥ 1990	≥ 25	≥ 955	≥ 12.0	302 ~ 326	38 ~ 41	20~180	﹣0.110	﹣0.50
42UH	1.29 ~ 1.34	1.29 ~ 1.34	≥ 1990	≥ 25	≥ 979	≥ 12.3	318 ~ 350	40 ~ 44
45UH	1.33 ~ 1.38	1.33 ~ 1.38	≥ 1990	≥ 25	≥ 1011	≥ 12.7	342 ~ 366	43 ~ 46
48UH	1.36 ~ 1.40	1.36 ~ 1.40	≥ 1990	≥ 25	≥ 1035	≥ 13.0	358 ~ 382	45 ~ 48
38EH	1.22 ~ 1.26	1.22 ~ 1.26	≥ 2388	≥ 30	≥ 931	≥ 11.7	287 ~ 310	36 ~ 39	20~200	﹣0.115	﹣0.45
40EH	1.25 ~ 1.29	1.25 ~ 1.29	≥ 2388	≥ 30	≥ 955	≥ 12.0	302 ~ 326	38 ~ 41
42EH	1.28 ~ 1.32	1.28 ~ 1.32	≥ 2388	≥ 30	≥ 979	≥ 12.3	318 ~ 350	40 ~ 44
45EH	1.32 ~ 1.37	1.32 ~ 1.37	≥ 2388	≥ 30	≥ 1011	≥ 12.7	342 ~ 366	43 ~ 46
35TH	1.18 ~ 1.24	1.18 ~ 1.24	≥ 2786	≥ 35	≥ 899	≥ 11.3	263 ~ 295	33 ~ 37	20~250	﹣0.115	﹣0.40
38TH	1.22 ~ 1.26	1.22 ~ 1.26	≥ 2786	≥ 35	≥ 931	≥ 11.7	287 ~ 310	36 ~ 39
40TH	1.25 ~ 1.29	1.25 ~ 1.29	≥ 2786	≥ 35	≥ 955	≥ 12.0	302 ~ 326	38 ~ 41

This parameters tables are best viewed in desktop view

name of parameter		unit	reference value	name of parameter		unit	reference value
the Curie temperature		℃	310~400	pyroconductivity		W/m·℃	8～10
density		g/cm3	7.4~7.7	Young modulus		GPa	150~200
Vickers hardness		HV	500～700	electrical resistivity	C∥	μΩ·m	1.4～1.6
recoil permeability		/	1.02~1.08	electrical resistivity	C⊥	μΩ·m	1.2～1.4
compressive strength		MPa	1000～1100	coefficient of thermal expansion	C∥	10-6/℃	4～9
bending strength		MPa	150～400	coefficient of thermal expansion	C⊥	10-6/℃	－2～0
maximum working temperature	N	M	H	SH	UH	EH	TH
maximum working temperature	80℃	100℃	120℃	150℃	180℃	200℃	250℃

Note: 1. C∥ is the value measured in the easy magnetization direction, and C⊥ is the value measured in the perpendicular to the direction.

This parameters tables are best viewed in desktop view

Demagnetization curve

Demagnetization curves of TH series magnets at different temperatures

. 35 TH

. 38TH

38TH 产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Demagnetization curves of EH series magnets at different temperatures

. 38 EH

. 40EH

38EH产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Demagnetization curves of UH series magnets at different temperatures

. 42 UH

. 45 UH

42UH产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Demagnetization curves of SH series magnets at different temperatures

. 45 SH

. 48 SH

45SH产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Demagnetization curves of M series magnets at different temperatures

. 48 M

. 50 M

48M产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Demagnetization curves of N series magnets at different temperatures

. N 50

. N 52

N50产品在不同工作点的磁通不可逆损失（典型值）与温度的关系

Coating introduction

Coating type	Thickness	Appearance	Corrosion resistanc					Remarks
			PCT	Salt Spray	Damp-heat	Acid and alkali	Oil
Zn (White Zn)	≥5 μm	Blue white	____	★★	★★★	____	★
Zn (Color-plated Zn)	≥5 μm	Iridescence	____	★★★	★★★★	____	★
Ni+Cu+Ni	≥15 μm	Silver white	★★★	★★★★	★★★★★	★★★	★★★
Ni+Cu+Ni+Sn	≥15 μm	Silver white	★★★★	★★★★	★★★★★	____	_____	Excellent weldability
Chemic Ni	≥5 μm	Silver white	★★★★	★★★★★	★★★★★	★★★	★★★
Epoxy	≥12 μm	Black or grey	★★★	★★★★★	★★★★★	★★★★★	★★★★	Poor wear resistance
Passivated	≤2 μm	Black or grey	——	——	★★★	——	★★★
Al	≥3 μm	Silver grey	★★★★	★★★	★★★★	——	★★★	High binding capacity
Al+Epoxy	≥15 μm	Black or grey	★★★★★	★★★★★	★★★★★	★★★★★	★★★★★	Poor wear resistance
Zn-Al	≥10 μm	Silver white or silver grey	★★★★★	★★★★★	★★★★★	——	★★★★★
Everluber	≥5 μm	Golden yellow	★★★★	★★★★	★★★★★	★★★★★	★★★★
Teflon	≥5 μm	Black	★★	★★★	★★★★★	★★★★★	★★★	Good wear resistance
Parylene coating	≥3 μm	Transparence	★★	★★★	★★★★★	★★★★★	★★★	Can be implanted into the human body

Note: The number of ★ reflects the anti-corrosion ability of coating, and five-star represents excellent corrosion resistance; “_” stands for not applicable.

This parameters tables are best viewed in desktop view

Size range

Shape	Product size range	More economical size range
Arc type	W≤150 mm H≤80 mm 0.5mm≤T≤60 W/H≤50 W/T≤20 mm	2.0mm≤W≤50 mm 1.0mm≤H≤40mm 1mm≤T≤60 W/H≤3 W/T≤10
Arc type	L≤180 mm W ≤80 mm H≤80mm ≤T≤60mm L/W≤10 L/H≤10 α≤180°	1mm≤L≤100 mm 1mm≤W ≤40mm 1mm≤H ≤40mm 2mm≤T≤40mm L/W≤5 L/H≤5 α≤90°
Bread type	L≤180mm W≤80mm L/W≤20 L/H≤20 H≤80mm	1.0mm≤L≤100mm 1.0mm≤W≤40mm L/W≤5 L/H≤5 1.0mm≤H≤40mm
Radial disc	D≤80 mm H≤60 mm D/H≤20	1.0mm≤D≤50mm 1.0mm≤H≤40mm D/H≤10
Radial ring	D≤80 mm d≥1 mm （D-d）/2≥1.4mm d/D≤0.8 D/35≤H≤1.5*D H≤60 mm	D≤50 mm d≥2 mm （D-d）/2≥2 mm d/D≤0.6 D/15≤H≤D 1.0mm≤H≤40 mm
Disc	D≤150 mm H≤60 mm D/H≤20	1.0mm≤D≤100mm 1.0mm≤H≤40mm D/H≤10
Axial ring	D ≤150mm d≥1mm （D-d）/2≥1.0mm d/D≤0.8 D/35≤H≤1.5*D H≤60 mm	D ≤100 mm d≥2 mm （D-d）/2≥2 mm d/D≤0.6 D/15≤H≤D 1.0mm≤H≤40 mm
Square block	L≤180 mm W ≤80 mm L/W≤20 L/H≤20 H≤80 mm	1mm≤L≤100 mm 1mm≤W ≤50mm L/W≤5 L/H≤5 1mm≤H≤50mm

Key features

NdFeB magnet is prepared by powder metallurgy method and its chemical composition is Nd2Fe14B, which has excellent magnetic properties.

Its advantages are high demagnetization resistance and high cost performance, while its disadvantages are relatively strong temperature dependence and relatively weak corrosion resistance, but after appropriate coating or electroplating plus choosing products of different degrees of coercivity in different use environments, NdFeB can be able to meet different customer requirements.