NdFeB Permanent Magnets

Engineering data first

Performance, design inputs and production evidence.

High-performance sintered neodymium magnets engineered around grade, operating temperature, geometry, coating and magnetization—not just a drawing.

11.7–15.2 kGsResidual Induction

33–57 MGOeEnergy Product

M / H / SH / UH / EH / TH / AHCoercivity classes

to ±0.02 mm typicalPrecision grinding

Material overview

What NdFeB Is — and Where the Design Risk Lives

Sintered NdFeB (Neodymium-Iron-Boron) is selected when magnetic energy density, compact size and motor efficiency are primary requirements. The grade name alone does not guarantee high-temperature performance; geometry, permeance coefficient, magnetization direction and the surrounding magnetic circuit determine the actual demagnetization margin.

Strength: highest energy density among mainstream commercial permanent-magnet families.
Trade-off: corrosion sensitivity requires the coating/environment to be engineered together.
Temperature: H / SH / UH / EH / TH / AH coercivity classes provide progressively higher demagnetization resistance.
Application review: for thin sections and open circuits, thermal loss can differ dramatically from catalog expectations.

APPLICATION RULETemperature → magnetic circuit → geometry → coercivity class → coating

We review the application before locking the grade.

Application engineering

Application & grade guidance

Application	Typical Spec	Why this material
EV / BLDC Motors	N42SH–N48SH	High torque density in a compact rotor
Sensors & Encoders	N35–N42	Strong stable field in small packages
Magnetic Separators	N42–N52	High field gradient for particle capture
Wind Generators	N42SH–N48SH	High energy with elevated-temperature margin
Acoustic Devices	N35–N45	Compact driver magnetic circuits
Magnetic Couplings	N38SH–N42SH	Torque transfer through sealed barriers

Grade architecture

Grade Families & Temperature Classes

Class	Typical reference temperature*	Selection logic	Typical applications
Standard N	~80°C	Maximum energy density where thermal margin is modest	Speakers, fixtures, sensors, general industrial
M	~100°C	Moderate added coercivity	Compact motors, actuators
H	~120°C	Higher demagnetization margin	Industrial motors, generators
SH	~150°C	Common automotive / traction-motor class	EV motors, wind generators, servos
UH	~180°C	High-temperature compact magnetic circuits	EV/HEV, actuators, aerospace-related industrial systems
EH	~200°C	Extreme thermal/demag margin	High-temperature motors and sensors
TH / AH	~220–230°C class	Special high-coercivity families	Application-specific high-temperature designs

*Reference values are grade-family guidance, not a universal safe part temperature. Final operating limit depends on geometry, magnetic circuit and allowed irreversible loss.

Full performance table

Complete technical grade data

Use the table as a selection reference. Final acceptance limits follow the approved drawing/specification and agreed test method.

Grade	Br mT (kGs)	Hcb kA/m (kOe)	Hcj kA/m (kOe)	(BH)max kJ/m³ (MGOe)	αBr %/°C	βHcj %/°C
N35	1180-1230 (11.8-12.3)	≥876 (≥11)	≥955 (≥12)	263-287 (33-36)	0.10-0.124	0.65-0.80
N38	1230-1260 (12.3-12.6)	≥899 (≥11.3)	≥955 (≥12)	287-310 (36-39)	0.10-0.124	0.65-0.80
N40	1260-1290 (12.6-12.9)	≥912 (≥11.5)	≥955 (≥12)	302-326 (38-41)	0.10-0.124	0.65-0.80
N42	1290-1330 (12.9-13.3)	≥923 (≥11.6)	≥955 (≥12)	318-342 (40-43)	0.10-0.124	0.65-0.80
N45	1330-1370 (13.3-13.7)	≥931 (≥11.7)	≥955 (≥12)	342-366 (43-46)	0.10-0.124	0.65-0.80
N48	1370-1400 (13.7-14.0)	≥939 (≥11.8)	≥955 (≥12)	366-390 (46-49)	0.10-0.124	0.65-0.80
N50	1390-1430 (13.9-14.3)	≥947 (≥11.9)	≥955 (≥12)	374-406 (47-51)	0.10-0.124	0.65-0.80
N52	1420-1460 (14.2-14.6)	≥947 (≥11.9)	≥955 (≥12)	390-414 (49-52)	0.10-0.124	0.65-0.80
N54	1450-1490 (14.5-14.9)	≥912 (≥11.5)	≥955 (≥12)	406-438 (51-55)	0.10-0.124	0.65-0.80
N56	1480-1520 (14.6-15.2)	≥860 (≥10.8)	≥876 (≥11)	422-454 (52-57)	0.10-0.124	0.65-0.80
35M	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥1114 (≥14)	263-287 (33-36)	0.10-0.124	0.60-0.75
38M	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥1114 (≥14)	287-310 (36-39)	0.10-0.124	0.60-0.75
40M	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥1114 (≥14)	302-326 (38-41)	0.10-0.124	0.60-0.75
42M	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥1114 (≥14)	318-342 (40-43)	0.10-0.124	0.60-0.75
45M	1330-1370 (13.3-13.7)	≥1002 (≥12.6)	≥1114 (≥14)	342-366 (43-46)	0.10-0.124	0.60-0.75
48M	1370-1400 (13.7-14.0)	≥1027 (≥12.9)	≥1114 (≥14)	366-390 (46-49)	0.10-0.124	0.60-0.75
50M	1390-1430 (13.9-14.3)	≥1035 (≥13.0)	≥1114 (≥14)	374-406 (47-51)	0.10-0.124	0.60-0.75
52M	1420-1460 (14.2-14.6)	≥995 (≥12.5)	≥1114 (≥14)	390-414 (49-52)	0.10-0.124	0.60-0.75
54M	1450-1490 (14.5-14.9)	≥995 (≥12.5)	≥1114 (≥14)	406-438 (51-55)	0.10-0.124	0.60-0.75
30H	1080-1140 (10.8-11.4)	≥827 (≥10.4)	≥1353 (≥17)	223-247 (28-31)	0.09-0.120	0.55-0.70
33H	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥1353 (≥17)	247-271 (31-34)	0.09-0.120	0.55-0.70
35H	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥1353 (≥17)	263-287 (33-36)	0.09-0.120	0.55-0.70
38H	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥1353 (≥17)	287-310 (36-39)	0.09-0.120	0.55-0.70
40H	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥1353 (≥17)	302-326 (38-41)	0.09-0.120	0.55-0.70
42H	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥1353 (≥17)	318-342 (40-43)	0.09-0.120	0.55-0.70
45H	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥1353 (≥17)	342-366 (43-46)	0.09-0.120	0.55-0.70
48H	1370-1400 (13.7-14.0)	≥1035 (≥13.0)	≥1353 (≥17)	366-390 (46-49)	0.09-0.120	0.55-0.70
50H	1390-1430 (13.9-14.3)	≥1058 (≥13.3)	≥1353 (≥17)	374-406 (47-51)	0.09-0.120	0.55-0.70
52H	1420-1460 (14.2-14.6)	≥1074 (≥13.5)	≥1353 (≥17)	390-414 (49-52)	0.09-0.120	0.55-0.70
54H	1450-1490 (14.5-14.9)	≥1074 (≥13.5)	≥1274 (≥16)	406-438 (51-55)	0.09-0.120	0.55-0.70
30SH	1080-1140 (10.8-11.4)	≥827 (≥10.4)	≥1592 (≥20)	223-247 (28-31)	0.09-0.120	0.50-0.65
33SH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥1592 (≥20)	247-271 (31-34)	0.09-0.120	0.50-0.65
35SH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥1592 (≥20)	263-287 (33-36)	0.09-0.120	0.50-0.65
38SH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥1592 (≥20)	287-310 (36-39)	0.09-0.120	0.50-0.65
40SH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥1592 (≥20)	302-326 (38-41)	0.09-0.120	0.50-0.65
42SH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥1592 (≥20)	318-342 (40-43)	0.09-0.120	0.50-0.65
N42SH-HRE	1310-1330 (13.1-13.3)	≥1020 (≥12.8)	≥1671 (≥21.0)	333-341 (42.0-43.0)	-0.125	-0.600
45SH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥1592 (≥20)	342-366 (43-46)	0.09-0.120	0.50-0.65
48SH	1370-1400 (13.7-14.0)	≥1035 (≥13.0)	≥1592 (≥20)	366-390 (46-49)	0.09-0.120	0.50-0.65
50SH	1390-1430 (13.9-14.3)	≥1058 (≥13.3)	≥1592 (≥20)	374-406 (47-51)	0.09-0.120	0.50-0.65
52SH	1420-1460 (14.2-14.6)	≥1074 (≥13.5)	≥1512 (≥19)	390-414 (49-52)	0.09-0.120	0.50-0.65
N54SH	1460-1480 (14.6-14.8)	≥1136 (≥14.3)	≥1751 (≥22.0)	413-421 (52.0-53.0)	-0.120	-0.600
28UH	1040-1090 (10.4-10.9)	≥780 (≥9.8)	≥1990 (≥25)	207-231 (26-29)	0.09-0.110	0.50-0.60
30UH	1080-1140 (10.8-11.4)	≥827 (≥10.4)	≥1990 (≥25)	223-247 (28-31)	0.09-0.110	0.50-0.60
33UH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥1990 (≥25)	247-271 (31-34)	0.09-0.110	0.50-0.60
35UH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥1990 (≥25)	263-287 (33-36)	0.09-0.110	0.50-0.60
38UH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥1990 (≥25)	287-310 (36-39)	0.09-0.110	0.50-0.60
40UH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥1990 (≥25)	302-326 (38-41)	0.09-0.110	0.50-0.60
42UH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥1990 (≥25)	318-342 (40-43)	0.09-0.110	0.50-0.60
45UH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥1990 (≥25)	342-366 (43-46)	0.09-0.110	0.50-0.60
48UH	1360-1400 (13.6-14.0)	≥1035 (≥13.0)	≥1990 (≥25)	358-390 (45-49)	0.09-0.110	0.50-0.60
N52UH	1440-1460 (14.4-14.6)	≥1120 (≥14.1)	≥2069 (≥26.0)	402-410 (50.5-51.5)	-0.115	-0.500
28EH	1040-1090 (10.4-10.9)	≥780 (≥9.8)	≥2388 (≥30)	207-231 (26-29)	0.09-0.110	0.45-0.55
30EH	1080-1140 (10.8-11.4)	≥827 (≥10.4)	≥2388 (≥30)	223-247 (28-31)	0.09-0.110	0.45-0.55
33EH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥2388 (≥30)	247-271 (31-34)	0.09-0.110	0.45-0.55
35EH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥2388 (≥30)	263-287 (33-36)	0.09-0.110	0.45-0.55
38EH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥2388 (≥30)	287-310 (36-39)	0.09-0.110	0.45-0.55
40EH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥2388 (≥30)	302-326 (38-41)	0.09-0.110	0.45-0.55
42EH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥2388 (≥30)	318-342 (40-43)	0.09-0.110	0.45-0.55
45EH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥2308 (≥29)	342-366 (43-46)	0.09-0.110	0.45-0.55
N45AH	1340-1350 (13.4-13.5)	≥1039 (≥13.1)	≥2865 (≥36.0)	342-350 (43.0-44.0)	-0.115	-0.400
N50EH	1410-1430 (14.1-14.3)	≥1097 (≥13.8)	≥2467 (≥31.0)	385-392 (48.5-49.2)	-0.115	-0.450
28TH	1040-1090 (10.4-10.9)	≥780 (≥9.8)	≥2786 (≥35)	207-231 (26-29)	0.09-0.110	0.40-0.50
30TH	1080-1140 (10.8-11.4)	≥827 (≥10.4)	≥2786 (≥35)	223-247 (28-31)	0.09-0.110	0.40-0.50
33TH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥2786 (≥35)	247-271 (31-34)	0.09-0.110	0.40-0.50
35TH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥2786 (≥35)	263-287 (33-36)	0.09-0.110	0.40-0.50
38TH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥2786 (≥35)	287-310 (36-39)	0.09-0.110	0.40-0.50
40TH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥2786 (≥35)	302-326 (38-41)	0.09-0.110	0.40-0.50
42TH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥2706 (≥34)	318-342 (40-43)	0.09-0.110	0.40-0.50
G-52H	1430-1460 (14.3-14.6)	≥1074 (≥13.5)	≥1353 (≥17)	398-422 (50-53)	0.11-0.13	0.60-0.70
G-55H	1460-1500 (14.6-15.0)	≥1098 (≥13.8)	≥1353 (≥17)	421-446 (53-56)	0.11-0.13	0.60-0.70
G-48SH	1370-1400 (13.7-14.0)	≥1035 (≥13.0)	≥1600 (≥20)	366-390 (46-49)	0.11-0.13	0.60-0.65
G-50SH	1400-1430 (14.0-14.3)	≥1058 (≥13.3)	≥1600 (≥20)	374-406 (47-51)	0.11-0.13	0.60-0.65
G-52SH	1430-1460 (14.3-14.6)	≥1074 (≥13.5)	≥1600 (≥20)	398-422 (50-53)	0.11-0.13	0.60-0.65
G-55SH	1460-1500 (14.6-15.0)	≥1098 (≥13.8)	≥1600 (≥20)	421-446 (53-56)	0.11-0.13	0.60-0.65
G-42UH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥1990 (≥25)	318-342 (40-43)	0.11-0.12	0.50-0.60
G-45UH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥1990 (≥25)	342-366 (43-46)	0.11-0.12	0.50-0.60
G-48UH	1370-1400 (13.7-14.0)	≥1035 (≥13.0)	≥1990 (≥25)	366-390 (46-49)	0.11-0.12	0.50-0.60
G-50UH	1400-1430 (14.0-14.3)	≥1058 (≥13.3)	≥1990 (≥25)	374-406 (47-51)	0.11-0.12	0.50-0.60
G-52UH	1430-1460 (14.3-14.6)	≥1074 (≥13.5)	≥1990 (≥25)	398-422 (50-53)	0.11-0.12	0.50-0.60
G-33EH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥2388 (≥30)	247-271 (31-34)	0.10-0.12	0.45-0.55
G-35EH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥2388 (≥30)	263-287 (33-36)	0.10-0.12	0.45-0.55
G-38EH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥2388 (≥30)	287-310 (36-39)	0.10-0.12	0.45-0.55
G-40EH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥2388 (≥30)	302-326 (38-41)	0.10-0.12	0.45-0.55
G-42EH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥2388 (≥30)	318-342 (40-43)	0.10-0.12	0.45-0.55
G-45EH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥2388 (≥30)	342-366 (43-46)	0.10-0.12	0.45-0.55
G-48EH	1370-1400 (13.7-14.0)	≥1035 (≥13.0)	≥2388 (≥30)	366-390 (46-49)	0.10-0.12	0.45-0.55
G-50EH	1400-1430 (14.0-14.3)	≥1035 (≥13.0)	≥2388 (≥30)	374-406 (47-51)	0.10-0.12	0.45-0.55
G-33TH	1140-1180 (11.4-11.8)	≥860 (≥10.8)	≥2785 (≥35)	247-271 (31-34)	0.095-0.11	0.42-0.52
G-35TH	1180-1230 (11.8-12.3)	≥899 (≥11.3)	≥2785 (≥35)	263-287 (33-36)	0.095-0.11	0.42-0.52
G-38TH	1230-1260 (12.3-12.6)	≥923 (≥11.6)	≥2785 (≥35)	287-310 (36-39)	0.095-0.11	0.42-0.52
G-40TH	1260-1290 (12.6-12.9)	≥947 (≥11.9)	≥2785 (≥35)	302-326 (38-41)	0.095-0.11	0.42-0.52
G-42TH	1290-1330 (12.9-13.3)	≥971 (≥12.2)	≥2785 (≥35)	318-342 (40-43)	0.095-0.11	0.42-0.52
G-45TH	1330-1370 (13.3-13.7)	≥1003 (≥12.6)	≥2706 (≥34)	342-366 (43-46)	0.095-0.11	0.42-0.52
G-54H	1440-1470 (14.4-14.7)	≥1074 (≥13.5)	≥1353 (≥17)	398-422 (50-53)	0.09-0.12	0.55-0.70
G-56H	1460-1500 (14.6-15.0)	≥1074 (≥13.5)	≥1274 (≥16)	406-438 (51-55)	0.09-0.12	0.55-0.70
G-54SH	1440-1470 (14.4-14.7)	≥1074 (≥13.5)	≥1592 (≥20)	398-422 (50-53)	0.09-0.12	0.50-0.65
G-56SH	1460-1480 (14.6-14.8)	≥1035 (≥13.0)	≥1512 (≥19)	406-438 (51-55)	0.09-0.12	0.50-0.65
G-54UH	1430-1470 (14.3-14.7)	≥1035 (≥13.0)	≥1910 (≥24)	390-422 (49-53)	0.09-0.11	0.50-0.60

Geometry, machining & dimensional capability

Discs & cylinders

Axial or diametric magnetization; sliced and ground diameters.

Blocks & rectangles

As-sintered or ground on selected/all faces.

Rings

Axial/radial magnetization, controlled ID/OD concentricity.

Arcs & segments

Rotor/stator segments including skewed geometry on request.

Custom features

Holes, slots and notches reviewed for feasibility and edge/chipping risk.

Tolerance strategy

Specify tight tolerance only where functionally required; DFM review identifies cost-sensitive dimensions.

Process	Typical Tolerance	Notes
As-sintered	±0.1 mm	Most economical for non-critical faces
Sliced / profile-ground	±0.05 mm	Standard for blocks and arc dimensions
Centerless / surface ground	±0.02 mm	Mating faces and press-fit diameters
Parallelism / perpendicularity	Per drawing	Confirmed during DFM review

Coatings & corrosion protection

Coating	Typical Thickness	Reference Salt Spray	Typical Use
Ni-Cu-Ni	15–20 µm	48 h+	General indoor / protected applications
Epoxy	15–25 µm	72 h+	Humidity / marine-oriented protection
Zinc	8–12 µm	24 h+	Cost-sensitive dry environments
Parylene C	10–15 µm	240 h+	High-protection / specialty applications

Salt-spray performance is process/specification dependent. Final requirements are agreed per project.

Magnetization patterns

Axial

Through thickness; common for discs, blocks and rings.

Diametric

Across diameter; common for rotors and cylindrical sensors.

Radial

Inside-to-outside or outside-to-inside orientation for rings.

Multi-pole

2 to 60+ poles where fixture and geometry permit; encoders, sensors and motor rings.

Skewed

Angled pole pattern for selected cogging/noise reduction concepts.

Verification

Flux / pole pattern can be checked with the agreed fixture and measurement method.

Manufacturing

Manufacturing Route — From Alloy to Finished Magnet

01

Alloy / strip casting

Raw material chemistry and alloy preparation define the starting magnetic potential.

02

Hydrogen decrepitation & milling

Controlled powder preparation targets particle size and oxygen control.

03

Orientation & pressing

Powder is aligned in a magnetic field before compaction.

04

Vacuum sintering & heat treatment

Density and microstructure are developed under controlled thermal cycles.

05

Machining / slicing / grinding

Finished geometry is produced with diamond or specialized cutting/grinding processes.

06

Coating

Ni-Cu-Ni, epoxy, Zn, Parylene or project-specific systems are applied as required.

07

Magnetization

Axial, diametric, radial, multipole or custom magnetization is applied with suitable fixtures.

08

Final inspection

Magnetic, dimensional, coating and visual checks are completed to the agreed control plan.

Manufacturing network: NdFeB / SmCo production in Ningbo and the newer Mianyang facility; the Mianyang site includes extensive slicing capacity, automated chamfering/cleaning and optical dimensional inspection. Facility and equipment photography is shared during supplier qualification.

Supply continuity

Rare-Earth Export & Compliance Support

Material review

Review whether controlled rare-earth elements or compositions are relevant to the ordered grade.

Heavy-rare-earth alternatives

Where technically feasible, evaluate lower-heavy-rare-earth or alternative grade routes against the real operating condition.

Classification & documentation

Support product/specification review, customs documentation and export classification at project level.

License support

Assist customers with information and documentation needed for lawful export-license applications where required.

Export-control treatment depends on the actual product, composition, specifications, destination and regulations in force at shipment. We do not present product-format changes as a method to bypass regulation.

Quality assurance

Inspection, traceability & pre-shipment verification

Magnetic-property verification

CoA / magnetic-property results can include Br, Hcb, Hcj and (BH)max according to the agreed inspection plan.

Dimensional inspection

Gauge, optical inspection or CMM/3D optical measurement can be used according to geometry and critical dimensions.

See Before We Ship

Before shipment, we can provide a real-time inspection video showing the product, equipment, measurement process and actual displayed data for remote customer verification.

Project documentation

FAI / PPAP / RoHS / REACH / traceability documents are available according to project and customer requirements.

Technical library

Technical PDF downloads

All technical PDFs in this library are hosted locally on empiremagnets.com and use the current Ningbo Empire document identity and revision format.

Engineering answers

Frequently asked questions

How do I select an NdFeB grade?

Start from the operating temperature, target flux/energy, geometry and permeance coefficient. Higher coercivity classes are selected when thermal or demagnetizing margin requires them; the highest energy grade is not automatically the best choice.

What does maximum operating temperature mean?

It is not a universal part temperature limit. Safe temperature depends on the magnet working point, geometry, circuit condition and required irreversible loss limit. We review the actual application before final grade selection.

Can NdFeB be used outdoors?

Yes, but surface protection and sealing must match the environment. Coating selection should be tied to humidity, salt exposure, bonding and dimensional requirements.

What information speeds up quotation?

Drawing, grade or magnetic target, operating temperature, coating, magnetization direction, annual volume, inspection method and end application.

Send the drawing—and tell us what it has to do.

Application, operating temperature, magnetic target, environment, geometry, magnetization and annual volume help us recommend the right route before quotation.

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