Sintered NdFeB magnet Neodymium Magnet

NdFeBhigh-energyhigh-performance

Neodymium Magnet is a permanent magnet manufactured from an alloy of neodymium, iron and boron forming the Nd2Fe14B tetragonal crystalline structure. These magnets are the strongest type of commercially available permanent magnets and are used where high magnetic performance is required.

Overview
The most powerful magnets available, sintered NdFeB magnets (Nd2Fe14B) are produced by powder metallurgical processes. They are hard and brittle, have very high remanence and coercive force, high energy product ((BH)max up to 51 MGOe), and offer a high performance-to-cost ratio. Intrinsic coercive force can exceed 30,000 Oe. Sintered NdFeB magnets are reactive with moisture and oxygen and are prone to corrosion; surface treatments such as gold, nickel, zinc, tin plating and epoxy resin coatings are commonly applied depending on the application environment. Strip casting and HDDR technologies allow manufacturing of high-performance grades (including >N52).

Sintered NdFeB — key material notes

• Chemical composition and structure: Nd2Fe14B (tetragonal).
• Mechanical: hard and brittle; grinding and slicing possible but require care.
• Corrosion: poorest corrosion resistance among common magnetic materials; coatings recommended for many applications.
• Thermal stability: reversible temperature coefficient of Br approx. -0.100 to -0.126 %/°C; working stability typically up to ~80°C for low Hci grades and can exceed 200°C for high Hci (high-temperature) grades.
• Performance: very high remanence, coercivity and energy product; (BH)max can reach up to 51 MGOe.
• Surface treatments available: gold, nickel, zinc, tin plating, epoxy resin coating.

Magnetic Properties of Sintered NdFeB Magnets
(table represented as grade rows)

• Grade — Br (mT / KGs) — Hcb (kA/m / KOe) — Hcj (kA/m / KOe) — (BH)max (kJ/m3 / MGOe) — Highest Working Temperature (L/D ≥ 0.7)
• N33 — 1130-1170 mT (11.3-11.7 KGs) — ≥828 kA/m (≥10.4 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 247-271 kJ/m3 (31-34 MGOe) — 80 ℃
• N35 — 1170-1220 mT (11.7-12.2 KGs) — ≥860 kA/m (≥10.8 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 263-287 kJ/m3 (33-36 MGOe) — 80 ℃
• N38 — 1220-1250 mT (12.2-12.5 KGs) — ≥876 kA/m (≥11.0 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 287-310 kJ/m3 (36-39 MGOe) — 80 ℃
• N40 — 1250-1280 mT (12.5-12.8 KGs) — ≥876 kA/m (≥11.0 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 302-326 kJ/m3 (38-41 MGOe) — 80 ℃
• N42 — 1280-1320 mT (12.8-13.2 KGs) — ≥892 kA/m (≥11.2 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 318-342 kJ/m3 (40-43 MGOe) — 80 ℃
• N45 — 1320-1380 mT (13.2-13.8 KGs) — ≥892 kA/m (≥11.2 KOe) Hcb — ≥955 kA/m (≥12 KOe) Hcj — 342-366 kJ/m3 (43-46 MGOe) — 80 ℃
• N48 — 1380-1420 mT (13.8-14.2 KGs) — ≥923 kA/m (≥11.6 KOe) Hcb — ≥876 kA/m (≥10.8 KOe) Hcj — 366-390 kJ/m3 (?46-49?) — 80 ℃
• N50 — 1380-1440 mT (13.8-14.4 KGs) — ≥923 kA/m (≥11.6 KOe) Hcb — ≥955 kA/m (≥12.1 KOe) Hcj — 376-408 kJ/m3 — 80 ℃
• N52 — 1430-1480 mT (14.3-14.8 KGs) — ≥860 kA/m (≥10.8 KOe) Hcb — ≥876 kA/m (≥11.0 KOe) Hcj — 398-422 kJ/m3 (50-53 MGOe) — 80 ℃
• Additional grades (M, H, SH, UH, EH, etc.) are listed with their respective Br, Hcb, Hcj, (BH)max and higher permissible working temperatures (e.g., many H/SH/UH types rated for 100–200 ℃ or higher) in the full properties table.

Physical Characteristics of Sintered NdFeB Magnets

• Curie Temperature: 310 ~ 340 ℃
• Reversible Temp. Coefficient of Br (20~100 ℃): -0.100 ~ -0.126 %/°C
• Reversible Temp. Coefficient of Hcj (20~100 ℃): -0.50 ~ -0.65 %/°C
• Density: ≥ 7.3 g/cm3
• Vickers Hardness: ~600
• Bending Strength: ~250 MPa
• Tensile Strength: ~80 MPa
• Compressive Strength: ~1050 MPa
• Specific Resistance: ~150 μΩ·cm
• Thermal Conductivity: ~9 W/(m·°C)
• Thermal Expansion: ~5 ×10-6 (parallel to orientation), ~-1.5 ×10-6 (vertical to orientation)
• Specific Heat: ~460 J/(kg·°C)

Caractéristiques / spécifications techniques

• Material system: Nd2Fe14B (neodymium-iron-boron).
• Manufacturing: sintered NdFeB (powder metallurgical process); advanced options include strip casting and HDDR to achieve high-performance grades (including >N52).
• Magnetic performance highlights: very high remanence and coercivity; (BH)max up to ~51 MGOe; intrinsic coercive force often >30,000 Oe.
• Surface protection options: gold, nickel, zinc, tin plating; epoxy resin coating available for corrosion protection.
• Thermal behavior: Br temperature coefficient ~-0.100 to -0.126 %/°C; working temperature depends on grade (typical standard grades up to ~80 ℃; special H/SH/UH/EH grades up to 100–200 ℃ or more).
• Mechanical/physical: density ≥7.3 g/cm3; Vickers hardness ~600; compressive strength ~1050 MPa.