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Cast AlNiCo Magnets

Cast Alnico magnets are permanent magnets composed primarily of aluminum (Al), nickel (Ni), cobalt (Co), iron (Fe), and copper (Cu), renowned for their exceptional temperature stability (up to 550°C), high residual induction (Br: 0.5–1.33 T), and intrinsic corrosion resistance. Manufactured through a casting process, they offer superior magnetic properties compared to sintered variants, with energy products (BH)max ranging from 1.13 to 9 MGOe (9–72 kJ/m³). Their ability to retain magnetization under extreme heat makes them ideal for aerospace, automotive, and industrial applications.

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Overview

Product Specifications

Material Composition:

Primary Elements: Aluminum (8–12%), Nickel (15–26%), Cobalt (5–36%), Copper (3–6%), Iron (balance)

Magnetic Properties:

Residual Induction (Br): 0.5–1.33 T (5,000–13,300 Gauss)

Coercivity (Hc): 30–1,750 kA/m (lower than rare-earth magnets)

Energy Product (BH)max: 1.13–9 MGOe (9–72 kJ/m³)

Temperature Performance:

Operating Range: -65°C to 550°C (short-term peaks up to 550°C)

Curie Temperature (Tc): 760–890°C

Physical Properties:

Density: 6.9–7.3 g/cm³; Hardness: 520–630 HV (brittle, requires diamond tools for machining)

Product Grades

Cast Alnico magnets are classified into isotropic (uniform magnetization) and anisotropic (directional magnetization, higher Br) types, with common grades including:

Alnico 2/3: Lower Br (0.5–0.7 T), used in sensors and instruments

Alnico 5: High Br (1.1–1.3 T), ideal for motors and generators

Alnico 8/9: Highest Hc (up to 1,750 kA/m), suited for extreme temperatures (e.g., aerospace)

Coatings

While Alnico magnets are naturally corrosion-resistant, optional coatings include:

None: Standard due to inherent oxidation resistance

Nickel (Ni): For solderability in electronics (e.g., PCB-mounted sensors)

Painted (Blue/Red): Pole identification (e.g., educational tools)

Gold/Zinc: Low-resistivity coatings for high-frequency applications

Applications

Cast Alnico magnets are widely used in:

Aerospace/Defense: Gyroscopes, radar systems (stable at 550°C)

Automotive: Speedometers, fuel sensors

Consumer Electronics: Guitar pickups, microphones (high acoustic clarity)

Industrial: Motors, magnetic separators

Packaging & Handling

Standard: Anti-static foam or plastic wraps, packed in cartons or wooden crates

Bulk Orders: Palletized with moisture barriers; magnetic shielding for air freight

Handling: Store with keepers to prevent demagnetization; avoid mechanical stress

FAQs

Are Cast Alnico magnets stronger than NdFeB?

No, but they outperform in thermal stability (NdFeB degrades above 150°C)

Can they be machined?

Yes, but only with diamond tools or EDM due to brittleness

Why choose Alnico over ferrite?

higher Br and temperature resistance, though ferrite is cheaper

Lead time for custom orders?

25–30 days for cast variants

Application

Manufacturing

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Electronics

In the electronics industry, magnets are essential components. Hard disk drives (HDDs) use tiny but powerful magnets to read and write data. The magnetic heads in HDDs can detect the magnetic fields representing digital information on the spinning disks. Speakers, whether in headphones...
Healthcare

The healthcare industry also benefits greatly from magnets. Magnetic Resonance Imaging (MRI) is one of the most significant medical applications. MRI machines use strong magnetic fields to generate detailed images of the inside of the human body. By aligning the protons in the body's tissues and detecting...
Automotive

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