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Neodymium Block Magnets

NdFeB (Neodymium) Rectangular & Block Magnets: Industrial & OEM Supply Guide

Product Specification & Technical Data
Neodymium block magnets (NdFeB permanent magnets) are precision-manufactured from an advanced rare-earth sintered neodymium-iron-boron alloy. They deliver exceptionally high magnetic energy density relative to their physical volume, enabling strong holding force and compact assembly designs for modern engineering and high-performance industrial applications.

Standard Grades & Magnetic Performance
N35 - N38: Maximum energy product of 33 ~ 38 MGOe. Applied in general industrial holding, magnetic separators, and consumer electronics.

N40 - N45: Maximum energy product of 40 ~ 45 MGOe. Applied in servo motors, sensors, and automated gripping fixtures.

N48 - N52: Maximum energy product of 48 ~ 52 MGOe. Applied in high-torque motors and restricted-space high-load assemblies.

Technical Specifications Table

Parameter	Specification Details
Material Composition	Sintered Neodymium-Iron-Boron (NdFeB)
Grade Range	N35 to N52; high-temperature grades (SH, UH, EH, AH) available
Dimensions	Custom-manufactured to engineering drawings (Length, Width, Thickness)
Magnetization Direction	Through Thickness, Through Length, Through Width, or Diametrical
Dimensional Tolerance	Standard +/- 0.1 mm, precision machining to +/- 0.03 mm available
Material Density	7.4 ~ 7.6 g/cm3
Surface Coatings	Ni-Cu-Ni (Nickel), Epoxy, Zinc, Gold, Parylene
Quality & Compliance	ISO 9001, IATF 16949 certified manufacturing lines; RoHS and REACH compliant

Operating Temperature Guidelines

Neodymium magnets experience a decrease in magnetic performance as operating temperatures rise. Selecting the correct thermal grade prevents irreversible magnetic loss.

Standard Grades (N35-N52):

Maximum working temperature up to 80 deg C.

M Series:

Up to 100 deg C.

H Series:

Up to 120 deg C.

SH Series:

Up to 150 deg C.

UH / EH / AH Series:

Up to 180 deg C ~ 230 deg C.

Surface Protection & Corrosion Resistance

Because neodymium magnets contain a high percentage of iron, unprotected material oxidizes rapidly in ambient air. We apply specialized plating layers to match rigorous operational environments:

Nickel-Copper-Nickel (Ni-Cu-Ni):

Standard three-layer plating (15 ~ 25 um total thickness). Provides a smooth finish and solid resistance to indoor atmospheric corrosion.

Epoxy Coating:

Applied via electrophoretic deposition. Offers enhanced moisture and salt-spray resistance for humid or outdoor conditions.

Zinc Plating:

A cost-effective industrial finish for enclosed mechanisms.

Quality Control & Batch Inspection Protocol

To maintain consistency across bulk manufacturing runs and meet stringent international OEM requirements, each production batch undergoes strict technical verification:

Raw Material Verification:

Testing chemical composition and intrinsic coercivity via spectrometer and BH hysteresis graph tracers.

Dimensional & Tolerance Checks:

Verified using digital calipers, micrometers, and optical comparators against customer CAD drawings.

Magnetic Flux & Pull Force Testing:

Measured with Helmholtz coils and pull-testers to ensure deviation stays within +/- 3% of target specifications.

Coating Adhesion & Integrity:

Cross-hatch tape testing and salt spray corrosion testing (48 ~ 96 hours depending on plating spec).

Packaging and Export Logistics

NdFeB magnets generate strong magnetic fields that can interfere with sensitive shipping equipment or trigger air freight regulations.

Shielding:

Inner packaging utilizes high-density iron sheet shielding or spaced air-gap positioning to contain the magnetic flux within permitted transport thresholds.

Cushioning:

Individual blocks are separated by non-magnetic foam spacers and packed in reinforced double-walled corrugated cartons with waterproof wrapping.

Lead Time & MOQ:

Standard production and sampling run on a 2 ~ 3 week lead time. Minimum Order Quantity (MOQ) is evaluated flexibly based on custom dimensions and material grades.

FAQ

Q: What are neodymium block magnets made of?

A: Neodymium block magnets are made from a rare earth alloy consisting mainly of neodymium (Nd), iron (Fe), and boron (B). This NdFeB material provides much higher magnetic strength than traditional ferrite or Alnico magnets.

Q: What is the strongest grade of neodymium block magnet available?

A: The highest commonly available commercial grades are N50 and N52. These grades provide maximum magnetic energy density and are often selected for applications requiring strong force in limited spaces.

Q: Can you manufacture custom size block magnets?

A: Yes. Custom block magnets can be manufactured according to customer drawings, dimensions, magnetic direction, coating requirements, and performance specifications.

Q: What coating is best for neodymium block magnets?

A: The best coating depends on the working environment:

Nickel coating is suitable for general indoor applications.
Epoxy coating provides better moisture and salt-spray resistance.
Zinc coating is commonly used for cost-effective industrial applications.

Q: What information should I provide when requesting a quotation?

A: For an accurate quotation, please provide:

Magnet dimensions and tolerance requirements
Magnet grade requirement
Magnetization direction
Order quantity / annual forecast
Surface coating
Application environment

Q: Do neodymium magnets lose their magnetism over time?

A: High-quality NdFeB magnets have excellent magnetic stability. Under normal operating conditions and within their temperature limits, they maintain most of their magnetic performance for many years.

Q: Are neodymium block magnets suitable for outdoor use?

A: Yes, but proper coating selection is critical. For outdoor or humid environments, epoxy-coated or specially protected magnets are strongly recommended to improve long-term corrosion resistance.

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