Magnetorheological Fluids: Smart Liquids in Magnetic Fields
What are magnetorheological fluids? A plain-language look at smart liquids that stiffen in a magnetic field, and where they are used.
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110 Articles
Knowledge base
Practical articles on permanent magnet materials — organized by topic, sortable by date or popularity.
Fundamentals
Core concepts of magnetism and magnet materials — read these first.
33 articlesMagnetic Levitation: Floating Without Touching
How magnetic levitation works in plain English: repelling poles, maglev trains, floating displays and frictionless bearings.
Magnetostriction: When Magnets Change Shape
Magnetostriction explained: why magnetic materials change shape slightly in a field, what causes transformer hum, and how sonar and actuators use the effect.
Ferrofluids: Liquid Magnets Explained
Ferrofluids explained: liquids full of nanoscale magnetic particles that spike up around magnets, and their real jobs in speakers, seals and dampers.
Electromagnets: Magnets You Can Switch On and Off
Electromagnets explained: a coil and iron core that switch on and off with current, and where they beat permanent magnets — from scrap yards to MRI machines.
Magnetic Recording and Storage: Data on Magnets
How magnetic recording stores data: tiny magnetized regions on hard drives and tape, read/write heads, and why solid-state drives took over.
Magnetization Curves: How Magnets Respond to Fields
What a magnetization (B-H) curve shows: saturation, the hysteresis loop, and why the demagnetization curve decides how strong a permanent magnet really is.
Magnetic Shielding: Blocking Magnetic Fields
Magnetic shielding explained: how high-permeability materials like mu-metal and steel redirect magnetic fields instead of blocking them, and where shields are used.
Physical Properties of Sintered NdFeB
Density, electrical resistivity and thermal expansion of sintered NdFeB — each explained in one sentence, and why it matters in motors, rings and assemblies.
Mechanical Properties of Sintered NdFeB
Why neodymium magnets chip and crack so easily: sintered NdFeB is hard but brittle. How to handle, machine and mount magnets without breaking them.
Permeability and Reluctance: The Circuit View of Magnets
Permeability and reluctance explained simply: why air gaps eat magnetic force, and why a steel return path makes the same magnet pull several times harder.
Bonded NdFeB Magnets: Magnets in Any Shape
Bonded magnets: magnetic powder mixed with plastic and molded into almost any shape — weaker than sintered, but wonderfully flexible.
Finite Element Simulation of Magnet Fields
What is finite element analysis (FEA)? A plain-language look at how engineers simulate magnet fields on a computer, why it matters, and the common software tools.
SmFeN: The Next-Generation Rare Earth Magnet
SmFeN is the promising newcomer of rare-earth magnets: nearly as strong as NdFeB in theory, better in heat — but it falls apart above 600 °C, so today it's bonded-only.
Hot-Pressed and Hot-Deformed NdFeB Magnets
Hot-pressed magnets: NdFeB powder squeezed at high temperature into a dense, strong magnet — the quiet workhorse behind power-steering motors in millions of cars.
Rare Earths and Magnetism: Why 4f Electrons Matter
Why are rare-earth magnets so strong? A plain-language answer: electrons deep inside rare-earth atoms make big magnetic moments that refuse to flip.
Why Are Rare Earth Magnets Expensive?
Why rare-earth magnets cost what they cost: the elements aren't rare — separating them is brutally hard, and the supply chain is concentrated in one country.
Magnet Lifetime: How Long Do Permanent Magnets Last?
How long do permanent magnets last? Decades — basically forever, if they are kept cool and protected from corrosion. Magnet aging explained in plain language.
Magnetic Materials: A Family Tree
How magnetic materials are classified: soft, semi-hard and permanent magnets — and the simple family tree from cheap ferrite to the strongest NdFeB.
Shape Anisotropy and Demagnetizing Fields
Why a long thin rod magnet holds its strength while a flat disc demagnetizes: shape anisotropy and the demagnetizing field, explained simply.
Eddy Currents in Permanent Magnets
Why magnets get hot inside motors: eddy currents explained in plain language, and the three ways motor designers keep magnets cool.
Magnetic Domains: How a Magnet Remembers Its Direction
What magnetic domains are: the tiny regions inside a magnet that line up when it is magnetized - and why that is how a magnet remembers its direction.
H, B, M, J: The Four Magnetic Quantities Explained
H, B, M and J in plain English: applied field, flux density, magnetization and polarization - one sentence each, with the units engineers use.
Magnet Grades Explained: What N35, N42H and N50SH Mean
How to read NdFeB grade names like N35, N42H and N50SH: the number is the strength, the letters are the heat resistance. Simple rule, examples and a reference table.
Why Magnets Hate Heat: Temperature Behavior Explained
Neodymium magnets get weaker as they heat up - some strength returns when they cool, past a limit the loss is permanent. Working temperatures by grade, explained simply.
Operating Point and Permeance Coefficient Pc
Why do flat magnets demagnetize so easily? The permeance coefficient Pc is a simple shape score: high Pc means hard to demagnetize, low Pc means fragile.
Magnetic Moment and Flux: Reliable Ways to Compare Magnets
What magnetic moment is, how it is measured with a Helmholtz coil, and why it beats surface gauss for comparing magnets.
Surface Field vs. Remanence vs. Flux: Don't Confuse Them
Surface field, remanence and flux are three different things. What each means and why mixing them up leads to wrong magnet specs.
Permanent Magnet Materials Compared: NdFeB, SmCo, Ferrite, AlNiCo
NdFeB, SmCo, ferrite and AlNiCo compared in one simple table: strength, heat tolerance, corrosion, cost and typical uses.
Magnetic Units: SI vs. CGS, and How to Convert
Tesla, gauss, oersted, A/m and MGOe explained in one line each — plus the three unit conversions you actually need.
How to Read a Hysteresis Loop and Demagnetization Curve
What the hysteresis loop and demagnetization curve are, and why every magnet datasheet number comes from them. Plain-language guide.
The Four Key Magnetic Parameters: Br, Hcb, Hcj, (BH)max
Br, Hcb, Hcj and (BH)max — the four numbers on every magnet datasheet — explained in plain language with a simple table.
What Is a Neodymium (NdFeB) Magnet?
What is a neodymium (NdFeB) magnet? A simple, plain-language explanation of the strongest permanent magnet: composition, types, strength and everyday applications.
Process & Manufacturing
How sintered NdFeB magnets are made, coated and finished.
24 articlesThe Magnet Supply Chain: From Ore to Finished Magnet
How rare-earth ore becomes a finished magnet: the supply chain stages, why lead times are long, and how buyers should plan.
Magnetizing Equipment: How Magnets Get Their Power
How magnetizing equipment works — capacitor-discharge pulses, coils and fixtures — and why magnetization happens last.
Magnet Packaging and Handling: Protect the Strength
How magnets should be packed and handled — cushioning, separation, moisture protection, and shipping rules for strong magnets.
Cerium Magnets: The Low-Cost NdFeB
Cerium is the most abundant and cheapest rare earth. Cerium magnets swap part of the praseodymium–neodymium for cerium — much lower cost, slightly lower strength and heat resistance.
Improving NiCuNi Coating Adhesion
NiCuNi plating keeps NdFeB magnets shiny and rust-proof — but a slippery surface means weak glue bonds. How surface tension controls adhesion, and how to check it with a dyne pen.
Parylene: The Conformal Coating for Magnets
Parylene is an ultra-thin, transparent polymer film grown from vapour in a vacuum chamber — it waterproofs and protects tiny magnets where plating cannot reach.
Sputtering Dy/Tb: Coercivity Enhancement Without Dip
Sputtering deposits a thin film of dysprosium or terbium on the magnet surface, then diffuses it along grain boundaries — big heat-resistance gain, a fraction of the heavy rare earth, almost no strength loss.
Passivation: A Thin, Invisible Protection
Passivation grows an ultra-thin, almost invisible protective film on magnets with a quick chemical dip — cheap, fast, and free of heavy metals.
Phosphating: Low-Cost Corrosion Protection
Phosphating is the low-cost way to protect NdFeB magnets during storage and to make epoxy stick: a thin grey phosphate film for pennies per part.
Machining NdFeB: Cutting, Grinding and Drilling
Sintered NdFeB is hard and brittle, so it is machined with diamond tools: cutting, grinding and drilling a sintered block into the exact shape on the drawing.
Electrophoretic Coating (E-coat) for Magnets
E-coat is electroplating with paint instead of metal: electricity pulls a tough, uniform epoxy film onto every corner of the magnet, protecting it from corrosion.
Sintering: From Green Body to Dense Magnet
Sintering welds pressed NdFeB powder into a solid magnet — like firing ceramics — with heat and a little liquid phase making it dense and strong.
Heat Treatment and Aging: Developing Coercivity
Tempering (aging) is the second, gentler heating step after sintering that fixes the grain boundaries and can multiply a NdFeB magnet's coercivity two to three times — explained simply.
Jet Milling: Making Micron Magnet Powder
Jet milling grinds magnet powder to a few microns using high-speed gas collisions — no grinding tools, and strict nitrogen protection against fire-hazard oxidation.
Field Pressing: Aligning the Powder
Field pressing gives a magnet its direction: powder is pressed inside a strong magnetic field so every tiny crystal lines up the same way.
Melting and Strip Casting
Melting and strip casting turn raw elements into alloy flakes: vacuum melting keeps the metal clean, and fast cooling on a copper wheel prevents weak spots.
Hydrogen Decrepitation (HD): The First Crush
Hydrogen decrepitation turns NdFeB alloy into powder without a crusher: hydrogen soaks in, the metal swells like rising dough, and it splits along its grain boundaries.
NdFeB Ingredients: What Each Element Does
What's inside an NdFeB magnet? Each element has a job: Nd drives the strength, Fe fills the volume, B holds it together, and Dy makes it heat-resistant.
NdFeB Corrosion: Why It Rusts, How Coatings Protect
Why neodymium magnets rust so fast, whether corrosion weakens them, and how coatings and simple storage habits keep them alive - explained simply.
Magnet Coatings: From NiCuNi to Epoxy
Why neodymium magnets need a protective coating, and how nickel, zinc, epoxy and other coatings compare - a simple guide to choosing the right one.
Magnet Orientation and Magnetization
Orientation fixes the magnetization direction while the magnet is pressed; magnetization switches the finished magnet on. Axial, diametral, radial and multipole — what to order and why it matters.
Grain Boundary Diffusion: Heavy Rare Earths Where They Matter
Grain-boundary diffusion (GBD) puts a thin shell of dysprosium or terbium on each crystal's surface — a big heat-resistance gain with a fraction of the heavy rare earth, and almost no loss of magnetic strength.
How Sintered NdFeB Magnets Are Made
How are NdFeB magnets made? The whole production process in five simple steps: melting, milling, pressing in a magnetic field, sintering, and coating.
Multipole Magnet Rings and Radial Orientation
A multipole ring is one magnet with many alternating N/S poles around its circumference — used in motors and rotary encoders for smooth rotation and precise position sensing.
Testing & Quality
Inspection methods, tolerances and quality control.
17 articlesNEMA and IE Efficiency Standards for Motors
IE1 to IE4 and NEMA Premium explained: what motor efficiency classes mean, why regulations push them, and how to compare motors.
UL Certification for Magnets and Magnetic Products
What UL certification means for magnets and magnetic assemblies, and what buyers should check before specifying UL-listed parts.
RoHS and REACH: Environmental Rules for Magnets
RoHS and REACH explained for magnet buyers: what the EU rules restrict, and how to get the compliance documents you need.
Magnet Testing Standards Compared: GB, IEC and More
Why magnet testing standards exist, and how GB/T, IEC and ASTM methods differ when measuring Br, Hcb, Hcj and (BH)max.
Weight-Loss Tests: HAST and PCT for Coatings
Weight-loss, HAST and PCT tests expose magnets to hot, high-pressure steam to measure corrosion resistance — explained simply.
Measuring Density and Physical Properties
How magnet density is measured by the classic water-displacement (Archimedes) method — and why density is one of the cheapest, fastest quality checks on a magnet.
Chemical Analysis of NdFeB: ICP-OES
What ICP analysis reveals about NdFeB magnets: it measures the elements inside — neodymium, praseodymium, dysprosium and more — and verifies that the recipe is right.
NdFeB Standards: GB/T 13560 and Friends
The Chinese standards behind every NdFeB datasheet: GB/T 13560 grades, GB/T 3217 measurement, and the supporting family — a simple map for buyers.
Hydrogen and Oxygen Analysis in NdFeB
Why oxygen and hydrogen content matter in NdFeB magnets — too much oxygen weakens the magnet, leftover hydrogen makes it brittle — and how both are measured.
Measuring Surface Field with a Gaussmeter
How to measure a magnet's surface field with a gaussmeter: which probe to choose, where to place it, and why the reading changes with position.
Dimension Inspection for Machined Magnets
How magnet dimensions are checked — calipers, micrometers, projectors and go/no-go gauges — and what tolerances mean in plain language.
Flux and Magnetic Moment Testing
Flux and magnetic moment measure the whole magnet, not one point. Why coil-based testing is more reliable than a single surface-field reading.
Testing the Demagnetization Curve: Closed vs Open Circuit
The B-H (demagnetization) curve is a magnet's certificate. How it is measured and why every magnet manufacturer tests it.
Measuring Coating Thickness on Magnets
How coating thickness on NdFeB magnets is measured — XRF, metallographic cross-sections and portable gauges — and why a thin spot is where rust starts. Plain-language guide.
Demagnetization: Causes, Prevention and Recovery
What makes a neodymium magnet lose its strength — heat, opposing magnetic fields and mechanical shock — and how to prevent it.
Magnet Testing: Common Inspection Methods
What happens before a magnet ships: appearance, dimensions, magnetic performance and sampling — the checks behind every test report.
NdFeB Dimensions and Tolerances
Why no two magnets come out exactly the same size, what size and shape tolerances mean, and how tight tolerances drive up cost.
Other Topics
Applications, materials comparison, selection and practical know-how.
36 articlesReluctance Motors: Magnet-Free Motor Design
Reluctance motors make torque without magnets: how the rotor follows the path of least magnetic resistance and where they are used.
Stepper Motors: Precise Positioning with Magnets
How stepper motors move in precise fixed steps, the two main types, and why 3D printers and CNC machines rely on open-loop positioning.
Servo Motors: Precision Motion Control
What makes a servo motor a servo: motor, encoder and closed-loop control for precise position, speed and torque in robots and machines.
PMSM: The Permanent Magnet Synchronous Motor
How a permanent magnet synchronous motor works: magnets on the rotor, sync with the AC field, and why EVs and appliances love its efficiency.
BLDC Motors: Brushless DC Made Simple
Brushless DC motors explained simply: electronic commutation, magnets on the rotor, and why they outlast and outshine brushed motors.
Magnetic Encoders: Measuring Position with Magnets
What is a magnetic encoder? A plain-English look at how magnets and sensors measure position and speed in motors and machines.
Magnetic Gears: Contact-Free Power Transmission
Magnetic gears explained in plain English: how torque passes through magnetic fields instead of touching teeth, and where they shine.
Magnetic Chucks and Fixtures: Holding Work Without Clamps
How magnetic chucks hold steel workpieces without clamps — perfect for grinding, milling and lathe work in any machine shop.
Magnets in Wireless Charging: Perfect Alignment
Why the magnets in your phone charger matter: perfect alignment means faster, more efficient wireless power transfer.
Magnets in Robotics: Motors, Grippers and Joints
From joint motors to magnetic grippers and encoders, here is how NdFeB magnets make modern robots small, fast and precise.
Magnets in Sensors: Position, Speed and More
How a magnet and a tiny chip work together to sense position, speed and more — without any physical contact or wear.
Magnets in Wind Turbines: Power from the Wind
How big neodymium magnets in direct-drive generators turn slow wind into clean electricity — and why they beat geared designs offshore.
Magnets in Aerospace: Reliability at High Stakes
Why aircraft rely on magnets in actuators, pumps and sensors, and why samarium-cobalt is often the material of choice up in the sky.
Magnets in Cars: From Motors to Sensors
Where magnets hide in a modern car: EV traction motors, sensors, speakers, power steering and more, and why they must survive heat and vibration.
Magnets in Medicine: MRI and Beyond
How magnets work in medicine: MRI scanners, surgical tools, dental attachments and implants, and why magnet therapy claims lack evidence.
Loudspeaker Magnets: Inside the Speaker
How the magnet inside a loudspeaker turns electric current into sound — and why ferrite, NdFeB and AlNiCo each shaped a generation of speakers.
Magnetic Separators in Industry
How magnetic separators use permanent magnets to pull iron and metal bits out of ore, food and waste — and when industry chooses ferrite or NdFeB.
Magnet Safety: Handling Strong Magnets Responsibly
Strong magnets can pinch skin, shatter, interfere with pacemakers and hurt children. The simple habits that keep NdFeB handling, storage and play safe.
Magnetic Couplings: Torque Without Contact
How magnetic couplings transmit torque through a wall with no contact and no leak: how the magnet rings lock together, and where pumps and mixers rely on them.
Where Are Permanent Magnets Used? An Overview
Motors, sensors, speakers, medical devices, cars and phones — a quick tour of where permanent magnets live and which material each application uses.
A Short History of Permanent Magnets
From lodestone to NdFeB in one minute: magnetite, steel, AlNiCo, ferrite, samarium-cobalt and the 1983 NdFeB breakthrough — what each era gave us.
Hollow-Cup Motors: Small, Fast, Magnet-Driven
Hollow-cup motors made simple: tiny coreless DC motors with instant response, smooth motion and quiet running - used in drones, robots and medical devices.
Hall Sensors: How They Detect Magnetic Fields
Hall sensors: tiny chips that turn a magnetic field into a voltage — the quiet eyes behind ABS brakes, brushless motors and e-bike throttles.
NdFeB Magnets in 3C Electronics
Where the magnets in your phone, earbuds and laptop actually live: speakers, camera autofocus, vibration motors and magnetic attachments - explained simply.
Air Freight Rules for Magnetized Parts
Flying magnetized parts: IATA Class 9 rules, the 2.1 m and 4.6 m field tests, shielding packaging, and the magnetic inspection report you need.
Shipping Magnets: Rules, Risks and Packaging
How to ship magnets safely: packaging that prevents chipping, shielding that contains the field, and the logistics rules that apply to every mode.
How to Specify a Magnet Requirement to a Supplier
What to send when you ask a magnet supplier for a quote: grade and performance, dimensions and tolerances, magnetization direction, coating and lead time.
Magnet Selection: A Practical Decision Flow
How to choose a magnet in five questions: size and shape, grade, coating, temperature and cost — plus the mistakes that kill samples and delay deliveries.
Recycled and Regenerated NdFeB Magnets
Old magnets contain valuable rare earths. How NdFeB scrap is recycled into new magnets or new raw material — and why it matters for cost and the environment.
AlNiCo Magnets: The Heat-Resistant Veteran
AlNiCo, the veteran magnet alloy that ruled before rare earths. Near-zero temperature coefficient, works at 450-550 °C, still used in instruments and sensors.
Ferrite Magnets: Cheap, Tough and Everywhere
Ferrite (ceramic) magnets are the cheapest permanent magnets on earth: rust-proof and hard to demagnetize, but weak per size. Meet them in fridge magnets and speakers.
Samarium-Cobalt (SmCo) Magnets: Built for High Temperatures
SmCo magnets shrug off 350 °C heat and corrosion with no coating needed. What they are, why they cost more than NdFeB, and where aerospace and sensors rely on them.
Permanent Magnets in Electric Motors
Why do electric motors use permanent magnets? A simple explanation of motor magnets: placement styles, why NdFeB is the favorite, and what motor makers look for.
Halbach Arrays: Field on One Side, Nothing on the Other
What is a Halbach array? A plain-language look at the magnet arrangement that puts a strong field on one side and almost nothing on the other - and where it is used.
Common Magnetic Circuit Configurations
Magnetic circuits made simple: how magnets, steel and air gaps work together, why air gaps are the bottleneck, and how closing the circuit boosts holding force.
How Much Can a Magnet Hold? Pull Force Explained
Pull force explained in plain English: how much a magnet can hold, how it is measured, why distance kills holding force, and how to make a magnet pull harder.
Sources
Content is compiled from public standards (GB/T 13560-2017 and equivalents), technical literature and manufacturer-published data. Performance figures are typical values or standard minimums — always verify against the supplier's certified test report.