Product Overview
Cast AlNiCo Magnets
Cast AlNiCo magnets can be supplied as cylinders, rings, blocks, gear-like profiles and custom machined shapes for sensors, meters, holding devices and high-temperature magnetic assemblies.
Cast AlNiCo magnets are permanent magnets made from aluminum, nickel, cobalt, iron and selected alloying elements through a casting, heat-treatment and magnetic orientation process. They are valued for excellent high-temperature stability, low reversible temperature coefficient, strong corrosion resistance and long-term magnetic stability in demanding instruments, sensors, meters, holding devices and high-temperature assemblies.
Compared with NdFeB and SmCo magnets, cast AlNiCo magnets have lower coercivity and must be designed with a proper magnetic circuit, suitable L/D ratio and protection against reverse demagnetizing fields. However, when used correctly, they offer very stable magnetic output, good mechanical strength, high operating temperature capability and excellent performance in precision measurement and temperature-sensitive applications.
Ningbo Vanguard Technologies supplies custom cast AlNiCo magnets in grades such as AlNiCo 2, AlNiCo 3, AlNiCo 5, AlNiCo 6, AlNiCo 8 and AlNiCo 9. Rods, bars, horseshoe magnets, U-shape magnets, cylinders, rings, blocks, sensor magnets and custom cast shapes can be manufactured according to drawings. Prototype samples are usually available within 15-25 days after grade, drawing, magnetization and tolerance are confirmed.
Quick View
Cast AlNiCo Magnet Selection Snapshot
AlNiCo 2-9
Common Grade Range
Grade selection is based on Br, coercivity, energy product, geometry and demagnetization risk.
450-550 °C
High Temperature Use
Excellent thermal stability for meters, sensors, instruments and hot industrial environments.
Cast Shape
Flexible Geometry
Rods, bars, blocks, rings, horseshoe magnets and complex cast profiles can be customized.
Low Hc
Design Attention
Open-circuit use, short L/D ratio and reverse fields require careful engineering review.
Temperature Stability Guide
AlNiCo 2
450 °C
AlNiCo 5
525 °C
AlNiCo 8
550 °C
AlNiCo 9
550 °C
Application Demand Focus
1Application ReviewTemperature, circuit, reverse field
2Grade MatchBr, Hcb, BHmax, stability
3Casting PlanMold, orientation, heat treatment
4MachiningGrinding, cutting, holes, finish
5InspectionSize, flux, polarity, documents
Industries Served
Key Applications
Precision Sensors
Stable reference fields for position sensors, speed sensors, reed switches and Hall sensor assemblies where long-term consistency is important.
Meters & Instruments
Used in analog meters, measuring instruments, calibration devices and scientific equipment requiring low magnetic drift.
High-Temperature Assemblies
Cast AlNiCo magnets can operate in hot industrial equipment, ovens, sensors and thermal cycling environments.
Holding & Lifting Devices
Horseshoe, U-shape and keeper-style AlNiCo magnets are used in holding tools, clamps and magnetic fixtures with steel return paths.
Audio & Speakers
Selected AlNiCo grades are used in speaker systems and audio devices where stable magnetic output and tonal characteristics are valued.
Education & Research
Durable cast AlNiCo rods, bars and horseshoe magnets are widely used in laboratories, training equipment and demonstration devices.
Magnetic Performance
Grade & Magnetic Properties
Common cast AlNiCo magnet grades. Values are typical at 20 °C and may vary by manufacturer, casting process, heat treatment, orientation and final geometry. Final grade selection should consider L/D ratio, magnetic circuit and demagnetizing field.
| Material | Grade | Br (T) | Br (kGs) | Hcb (kA/m) | Hcb (kOe) | (BH)max (kJ/m³) | (BH)max (MGOe) | Max. Operating Temp. (°C) | Temp. Coeff. Br (%/°C) | Typical Use |
|---|---|---|---|---|---|---|---|---|---|---|
| Cast AlNiCo | AlNiCo 2 | 0.70-0.76 | 7.0-7.6 | 40-48 | 0.50-0.60 | 10-13 | 1.25-1.65 | 450 | -0.02 | General sensors, instruments |
| Cast AlNiCo | AlNiCo 3 | 0.55-0.65 | 5.5-6.5 | 38-44 | 0.48-0.55 | 4-6 | 0.5-0.8 | 450 | -0.02 | Low-cost stable-field devices |
| Cast AlNiCo | AlNiCo 5 | 1.20-1.30 | 12.0-13.0 | 46-54 | 0.58-0.68 | 40-44 | 5.0-5.5 | 525 | -0.02 | Meters, sensors, holding magnets |
| Cast AlNiCo | AlNiCo 6 | 1.05-1.15 | 10.5-11.5 | 58-66 | 0.73-0.83 | 28-34 | 3.5-4.3 | 525 | -0.02 | Higher coercivity than AlNiCo 5 |
| Cast AlNiCo | AlNiCo 8 | 0.75-0.85 | 7.5-8.5 | 120-140 | 1.50-1.76 | 32-44 | 4.0-5.5 | 550 | -0.02 | Higher demagnetization resistance |
| Cast AlNiCo | AlNiCo 9 | 1.05-1.15 | 10.5-11.5 | 110-130 | 1.38-1.63 | 72-80 | 9.0-10.0 | 550 | -0.02 | High energy AlNiCo applications |
Custom Options
Custom Cast AlNiCo Magnet Specification Options
| Item | Available Options | Engineering Notes |
|---|---|---|
| Shape | Rod, bar, block, ring, disc, cylinder, horseshoe, U-shape, stepped and custom cast profile | Complex shapes are often more practical by casting than by machining from brittle stock. |
| Magnetization | Axial, diametrical, radial support, multi-pole support, custom fixture magnetization | AlNiCo should usually be magnetized after final machining and assembly when possible. |
| Tolerance | As-cast tolerance, ground tolerance, precision grinding, critical dimension inspection | Grinding is used for tighter dimensions, flatness and assembly interfaces. |
| Surface Finish | Ground, sand-blasted, polished, painted, plated, passivated or uncoated | AlNiCo has good corrosion resistance; coating is usually for appearance, bonding or handling. |
| Assembly Support | Steel keeper, yoke, housing, adhesive bonding, mechanical fixture and magnetic circuit review | Steel return paths help preserve magnetic performance and improve pull/field output. |
| Inspection | Dimension, surface flux, magnetic moment, polarity, demagnetization check and material report | Inspection plan is selected according to final application and drawing requirements. |
Engineering Selection
Design Points for Cast AlNiCo Magnets
L/D Ratio
AlNiCo magnets have low coercivity, so short open-circuit designs are more vulnerable to demagnetization. Long rods, keepers and closed magnetic circuits are preferred.
Temperature Stability
AlNiCo has excellent high-temperature capability and low reversible temperature coefficient, making it valuable for precision field stability.
Reverse Field Risk
External reverse fields, open-circuit storage and improper assembly can partially demagnetize AlNiCo magnets. Keeper design should be reviewed.
Casting & Machining
Casting supports complex geometry, while final grinding is used for precision surfaces. Holes, slots and thin walls should be reviewed before tooling.
Quality Control
Manufacturing & Inspection Capability
Casting Control
Alloy composition, mold design, casting defects, heat treatment and orientation process are controlled according to grade requirement.
Magnetic Inspection
Surface flux, magnetic moment, polarity, Br, Hcb and batch consistency can be checked according to specification.
Dimensional Inspection
Critical dimensions, flatness, angle, roundness, hole position, grinding finish and visual defects are inspected before shipment.
Documentation
Material certificate, dimensional report, magnetic report, coating report and RoHS/REACH documents are available on request.
Fast Quotation
Information Needed for Fast Quotation
For faster engineering review, please provide drawing or 3D file, grade or working temperature, dimensions and tolerance, magnetization direction, coating or finish requirement, magnetic circuit condition, sample quantity and annual volume. If the grade is not fixed, our team can recommend an AlNiCo option based on temperature, magnetic output and demagnetization risk.
Support
Frequently Asked Questions
When should I choose cast AlNiCo magnets?
Choose cast AlNiCo when the application needs high temperature stability, low magnetic drift, good corrosion resistance and stable output in instruments, sensors or holding assemblies with a proper magnetic circuit.
Why does AlNiCo require careful magnetic circuit design?
AlNiCo has relatively low coercivity, so short magnets, open-circuit storage or reverse fields can cause partial demagnetization. Keepers, higher L/D ratio and closed circuits help improve stability.
Can cast AlNiCo magnets be machined after casting?
Yes. Grinding, cutting and finishing can be performed for critical dimensions, but AlNiCo is hard and brittle, so complex machining features should be reviewed before production.
Do cast AlNiCo magnets need coating?
Usually AlNiCo has good corrosion resistance and can be used uncoated. Coating or painting may be added for appearance, identification, bonding, handling or special environmental requirements.
What is the lead time for custom cast AlNiCo magnets?
Prototype samples are typically 15-25 working days. Mass production is usually 30-45 working days depending on casting tooling, grade, machining, magnetization and quantity.
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