This page summarizes the magnetic and physical properties of sintered NdFeB magnets we manufacture, covering remanence (Br), coercivity (Hcj), maximum energy product ((BH)max) and the recommended working temperatures across grade series.
Sintered NdFeB offers the highest (BH)max of any permanent magnet material, but has a lower maximum operating temperature than SmCo or AlNiCo. Selecting the right grade series balances magnetic output with thermal stability and cost.
Key Specifications
| Specification | Value |
|---|---|
| Br remanence | 11.7 – 14.8 kGs (1.17 – 1.48 T) |
| Hcj coercivity | 10 – 28 kOe depending on series |
| (BH)max | 38 – 52 MGOe |
| Max working temp | 80 °C (N) to 200 °C (EH) |
| Curie temperature | 310 – 370 °C |
| Density | 7.4 – 7.6 g/cm³ |
| Vickers hardness | HV 500 – 600 |
| Corrosion | Susceptible — requires coating |
GRADE DATA
Magnetic Properties by Grade
Four grade families cover the range from general-purpose holding to high-temperature motor and sensor duty. All values below are typical room-temperature figures at 20 °C; they are production reference ranges, not minimum guarantees — confirm the grade and tolerances on your drawing with our engineers.
N-Series — Standard Grades (Br up to 15.3 kGs, up to 80 °C)
Swipe horizontally to see all columns
| No. | Grade | Magnet Property | Max Working Temp. Tw (°C) | |||
|---|---|---|---|---|---|---|
| Remanence, Br mT or kGs | Coercivity, Hcb kA/m or kOe | Intrinsic Coercivity, Hcj kA/m or kOe | Max Energy Product, (BH)max kJ/m³ or MGOe | |||
| 1 | N55 | 1470–1530 (14.7–15.3) | ≥860 (≥10.8) | ≥876 (≥11) | 414–438 (52–56) | 70 |
| 2 | N52 | 1430–1480 (14.3–14.8) | ≥860 (≥10.8) | ≥876 (≥11) | 398–422 (50–53) | 70 |
| 3 | N50 | 1400–1450 (14.0–14.5) | ≥860 (≥10.8) | ≥960 (≥12) | 382–406 (48–51) | 70 |
| 4 | N48 | 1380–1420 (13.8–14.2) | ≥836 (≥10.5) | ≥900 (≥11) | 366–390 (46–49) | 80 |
| 5 | N45 | 1320–1380 (13.2–13.8) | ≥876 (≥11.0) | ≥960 (≥12) | 342–366 (43–46) | 80 |
| 6 | N42 | 1280–1320 (12.8–13.2) | ≥923 (≥11.6) | ≥960 (≥12) | 318–342 (40–43) | 80 |
| 7 | N40 | 1250–1280 (12.5–12.8) | ≥923 (≥11.6) | ≥960 (≥12) | 302–326 (38–41) | 80 |
| 8 | N38 | 1220–1250 (12.2–12.5) | ≥899 (≥11.3) | ≥960 (≥12) | 287–310 (36–39) | 80 |
| 9 | N35 | 1180–1220 (11.8–12.2) | ≥868 (≥10.9) | ≥960 (≥12) | 263–287 (33–36) | 80 |
| 10 | N33 | 1130–1180 (11.3–11.8) | ≥836 (≥10.5) | ≥960 (≥12) | 247–270 (31–34) | 80 |
| 11 | N30 | 1080–1130 (10.8–11.3) | ≥796 (≥10) | ≥960 (≥12) | 223–247 (28–31) | 80 |
N-series covers the widest cost-performance band. N35–N42 suits most holding, clamping and sensor work; N48–N55 is chosen when magnet volume is tightly constrained and the assembly runs near room temperature.
Grain Boundary Diffusion (GBD) Grades — up to 220 °C
In grain boundary diffusion, terbium or dysprosium is applied to the surface of a finished magnet and diffused along the grain boundaries during heat treatment. The heavy rare earth concentrates where it is needed instead of being distributed through the whole body, so a high Hcj is reached with far less Dy/Tb than a conventionally alloyed grade — and with less loss of Br.
| Hcj kOe | 28 | 30 | 33 | 35 | 38 | 40 | 42 | 45 | 48 | 50 | 52 | 55 | Temp. max °C |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 40 | G28AH | G30AH | G33AH | G35AH | G38AH | G40AH | G42AH | G45AH | 220 | ||||
| 35 | G28EH | G30EH | G33EH | G35EH | G38EH | G40EH | G42EH | G45EH | G48EH | G50EH | 200 | ||
| 30 | G35UH | G38UH | G40UH | G42UH | G45UH | G48UH | G50UH | G52UH | G55UH | 180 | |||
| 25 | G45SH | G48SH | G50SH | G52SH | G55SH | 150 | |||||||
| 20 | G52H | G55H | 120 |
The diagram plots each GBD grade against maximum energy product and intrinsic coercivity. Moving down a row raises the maximum working temperature; moving right raises magnetic output.
H series · 120 °CSH series · 150 °CUH series · 180 °CEH series · 200 °CAH series · 220 °C
How the Diffusion Process Works
Before filming — Tb target (blue) above the NdFeB substrate (grey)
After filming — a thin Tb film is deposited on the surface
After GBD — Tb diffuses along the boundaries, forming a Tb-rich 2:1:4:1 phase
Magnet after
machining
machining
Pre-treatment
Apply HRE
(Tb or Dy)
(Tb or Dy)
Diffusion by
heat-treatment
heat-treatment
Annealing
HRE applied by
Option 1 — Magnetron sputtering
Option 2 — Spraying
Option 3 — Painting
Swipe horizontally to see all columns
| Grade | Magnet Property | Max Working Temp. Tw (°C) | |||
|---|---|---|---|---|---|
| Remanence, Br mT or kGs | Coercivity, Hcb kA/m or kOe | Intrinsic Coercivity, Hcj kA/m or kOe | Max Energy Product, (BH)max kJ/m³ or MGOe | ||
| G55H | 1440–1480 (14.4–14.8) | ≥1061 (≥13.3) | ≥1353 (≥17) | 398–422 (53–56) | 120 |
| G52H | 1410–1470 (14.1–14.7) | ≥1050 (≥13.2) | ≥1353 (≥17) | 398–422 (50–53) | 120 |
| G55SH | 1440–1480 (14.4–14.8) | ≥1050 (≥13.3) | ≥1592 (≥20) | 398–422 (53–56) | 150 |
| G52SH | 1430–1450 (14.3–14.5) | ≥1050 (≥13.2) | ≥1592 (≥20) | 406–430 (51–54) | 150 |
| G50SH | 1400–1450 (14.0–14.5) | ≥1035 (≥13.0) | ≥1592 (≥20) | 382–406 (48–51) | 150 |
| G48SH | 1370–1430 (13.7–14.3) | ≥1035 (≥13.0) | ≥1592 (≥20) | 366–390 (46–49) | 150 |
| G45SH | 1320–1370 (13.2–13.7) | ≥1003 (≥12.6) | ≥1592 (≥20) | 342–366 (43–46) | 150 |
| G52UH | 1410–1470 (14.1–14.6) | ≥1050 (≥13.2) | ≥1990 (≥25) | 398–422 (50–53) | 180 |
| G50UH | 1400–1450 (14.0–14.5) | ≥1035 (≥13.0) | ≥1990 (≥25) | 382–406 (48–51) | 180 |
| G48UH | 1370–1430 (13.7–14.3) | ≥1035 (≥13.0) | ≥1990 (≥25) | 366–390 (46–49) | 180 |
| G45UH | 1300–1360 (13.0–13.6) | ≥1003 (≥12.6) | ≥1990 (≥25) | 342–366 (43–46) | 180 |
| G42UH | 1280–1340 (12.8–13.4) | ≥907 (≥11.4) | ≥1990 (≥25) | 318–342 (40–43) | 180 |
| G40UH | 1260–1310 (12.6–13.1) | ≥907 (≥11.4) | ≥1990 (≥25) | 302–326 (38–41) | 180 |
| G50EH | 1400–1450 (14.0–14.5) | ≥1035 (≥13.0) | ≥2388 (≥30) | 382–406 (48–51) | 200 |
| G48EH | 1370–1430 (13.7–14.3) | ≥1035 (≥13.0) | ≥2388 (≥30) | 366–390 (46–49) | 200 |
| G45EH | 1300–1360 (13.0–13.6) | ≥1003 (≥12.6) | ≥2388 (≥30) | 342–366 (43–46) | 200 |
| G42EH | 1280–1320 (12.8–13.2) | ≥907 (≥11.4) | ≥2388 (≥30) | 318–342 (40–43) | 200 |
| G40EH | 1260–1310 (12.6–13.1) | ≥907 (≥11.4) | ≥2388 (≥30) | 302–326 (38–41) | 200 |
| G38EH | 1220–1270 (12.2–12.7) | ≥907 (≥11.4) | ≥2388 (≥30) | 287–310 (36–39) | 200 |
| G45AH | 1300–1360 (13.0–13.6) | ≥1003 (≥12.6) | ≥2786 (≥35) | 342–366 (43–46) | 220 |
| G42AH | 1280–1340 (12.8–13.4) | ≥907 (≥11.4) | ≥2786 (≥35) | 318–342 (40–43) | 220 |
| G40AH | 1260–1310 (12.6–13.1) | ≥907 (≥11.4) | ≥2786 (≥35) | 302–326 (38–41) | 220 |
| G38AH | 1220–1250 (12.2–12.5) | ≥907 (≥11.4) | ≥2786 (≥35) | 287–310 (36–39) | 220 |
| G35AH | 1160–1230 (11.6–12.3) | ≥812 (≥10.2) | ≥2786 (≥35) | 263–287 (33–36) | 220 |
GBD grades are quoted per grade and per coating. Because the process adds a heat cycle, lead time is typically 3–5 working days longer than for standard N-series grades, and small quantities are best consolidated into one diffusion batch.
All magnets are produced to order. Please provide grade, dimension (or drawing), magnetization direction, coating and quantity for quotation. Email sales@polemagnet.com or use the inquiry form — we reply within 24 hours.
FAQ
Sintered NdFeB Magnet Properties — FAQ
How do I choose between N35 and N52?
Higher grades (N48–N52) give more magnetic output per volume but are more expensive and slightly more brittle. For most holding applications N35–N42 offers the best cost-performance balance; N52 suits designs where magnet volume is strictly limited.
Why does coercivity matter for my application?
Hcj determines resistance to demagnetization from opposing fields and elevated temperature. Choose H/SH/UH/EH series when magnets work above 80 °C or near strong opposing magnetic fields.
Do you provide free samples for testing?
Yes, sample orders are welcome. Send your drawing or specification together with the intended application so our engineers can recommend the correct grade, magnetization direction and coating before we prepare samples.
Can the factory produce to my drawing with special tolerances?
Yes. We machine, grind and inspect to customer drawing tolerances. For sintered NdFeB the standard machining tolerance is ±0.05 mm and can be tightened to ±0.02 mm with diamond grinding where the geometry allows.
What is the difference between a GBD grade and a standard N-series grade?
A GBD grade such as G52SH starts from the same sintered NdFeB body as an N-series grade, but terbium or dysprosium is diffused along the grain boundaries after machining. Intrinsic coercivity rises from about 960 kA/m to 1592 kA/m or more while Br stays high, so the magnet works at 150-220 degC instead of 80 degC. In practice you get the output of a high-Br grade with the thermal stability of a high-coercivity grade.
Which grade should I choose for 150 degC or above?
Match the maximum working temperature first: SH for 150 degC, UH for 180 degC, EH for 200 degC and AH for 220 degC. Within that series pick the highest (BH)max whose Br still leaves margin for your air gap and permeance coefficient. Send the assembly drawing and operating temperature and our engineers will run the load-line calculation for you.
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