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Ceramic Arc Magnets

Ceramic Arc Magnets (Ferrite Arc Magnets)

Industrial-Grade Permanent Magnets for Electric Motors, Generators & Rotary Assemblies

Ceramic arc magnets, or ferrite arc magnets, are anisotropic or isotropic permanent magnets composed of strontium ferrite (SrFe12O19) or barium ferrite (BaFe12O19). Their curved geometry is engineered to match the inner or outer diameter of motor rotors and stators, maximizing magnetic flux distribution while minimizing air gaps compared to flat rectangular blocks.

Due to the intrinsic high electrical resistivity of ferrite ceramics (10^6--10^8 Ohm*cm), eddy current losses are heavily suppressed, making these magnets well-suited for continuous-duty motors and generators. As a cost-effective, high-volume alternative to rare-earth neodymium magnets, they provide stable performance up to 250°C with inherent chemical stability and complete immunity against rare-earth market volatility.

Key Performance Advantages

Optimized Flux Distribution:

The curved profile follows the exact circumference of the rotor or stator, reducing magnetic leakage and improving overall motor efficiency.

Low Eddy Current Losses:

High electrical resistivity limits parasitic currents, preventing excessive heat generation during high-speed continuous operation.

No Protective Coating Required:

Because the material is an oxidized ceramic rather than a metallic alloy, it does not rust or oxidize in humid environments. This eliminates the risk of coating delamination or failure.

Cost Stability & High-Volume Readiness:

Free of rare-earth elements, ferrite raw materials offer predictable pricing and reliable supply chains, significantly reducing procurement risks for high-volume brush/brushless motor production.

Long-Term Magnetic Stability:

Exhibiting high intrinsic coercivity (160--350 kA/m), these magnets resist natural demagnetization over decades of service under normal operating conditions.

Tight Dimensional Consistency:

Produced via precision pressing and CNC grinding to maintain strict tolerances for automated assembly lines.

Technical Specifications

Property	Typical Value / Range
Material Composition	Strontium Ferrite (SrFe12O19) / Barium Ferrite (BaFe12O19)
Magnetization Type	Isotropic or Anisotropic
Standard Grades	Y25, Y30, Y30BH, Y33, Y35 (Custom grades available)
Remanence (Br)	190--430 mT
Coercivity (Hcb)	135--310 kA/m
Intrinsic Coercivity (Hcj)	160--350 kA/m
Maximum Energy Product ((BH)max)	1.0--4.5 MGOe
Density	4.8--5.1 g/cm3
Max Operating Temperature	250°C
Curie Temperature	Approx. 450°C
Surface Finish	Ground or As-Sintered (No coating applied)
Color	Dark Gray

Manufacturing Process

Consistent magnetic performance relies on strict control over powder preparation, pressing alignment, and thermal profiles. The production workflow consists of:

Raw Material Preparation:

Blending high-purity iron oxide and strontium/barium carbonate powders.

Pressing & Orientation:

Automatic dry or wet pressing under a high magnetic field to align magnetic domains for anisotropic grades.

Sintering:

High-temperature firing in roller-hearth kilns above 1200°C to achieve full material densification.

Machining & Grinding:

CNC surface and profile grinding to achieve required outer diameter (OD), inner diameter (ID), and height tolerances.

Inspection:

Magnetic flux testing, demagnetization curve verification (Br, Hcj), dimensional gauging, and visual crack/chip checks.

Primary Applications

Electric Motors:

DC motors, BLDC motors, AC motors, servo motors, and stepper motors.

Automotive Actuators:

Power window motors, seat adjustment motors, HVAC blower motors, cooling fans, and fuel pumps.

Home Appliances:

Washing machine drain pumps, vacuum cleaner motors, hair dryer motors, and air conditioner fan drives.

Industrial Equipment:

Centrifugal pumps, auxiliary generators, industrial compressors, conveyor drives, and magnetic couplings.

Quality Control Standards

Every production batch is evaluated to ensure mechanical and magnetic reliability. Testing protocols include:

Hysteresis Graph Testing:

Measuring Br, Hcb, Hcj, and (BH)max using calibrated permeameters.

Dimensional Verification:

Utilizing optical comparators and digital micrometers to check radius and thickness tolerances.

Visual Inspection:

Screening for edge chipping, surface cracks, and structural flaws.

Traceability:

Batch numbers assigned to raw material lots for complete production traceability.

fAQ

Q: What is the difference between ceramic arc magnets and neodymium arc magnets?

A: Neodymium arc magnets provide much higher magnetic strength but are significantly more expensive and usually require protective coatings. Ceramic arc magnets offer excellent corrosion resistance, stable performance, and a much lower cost, making them ideal for high-volume motor production.

Q: Are ceramic arc magnets resistant to rust?

A: Yes. Ferrite magnets are ceramic materials rather than metallic alloys, so they do not rust under normal operating conditions and require no electroplated coating.

Q: Can you manufacture custom arc dimensions?

A: Yes. We manufacture according to customer drawings, including custom outer diameter, inner diameter, arc angle, thickness, height, and tolerances.

Q: What magnetization directions are available?

A: We can produce radial magnetization, parallel magnetization, axial magnetization, and multi-pole magnetization based on your motor design.

Q: What is the maximum operating temperature?

A: Most ceramic arc magnets can operate continuously at temperatures up to 250°C, depending on the grade and application.

Q: Do ceramic arc magnets lose magnetism over time?

A: Under normal operating conditions and within their specified temperature range, ceramic magnets retain their magnetic properties for many years. Ferrite materials have high resistance to demagnetization and excellent long-term stability.

Q: Can ceramic arc magnets be machined after magnetization?

A: Machining after magnetization is generally not recommended because ferrite is a hard and brittle ceramic material. Final dimensions are normally achieved through grinding before magnetization.

As one of the most professional ceramic arc magnets manufacturers and suppliers in China, we're featured by quality products and good service. Please rest assured to buy customized ceramic arc magnets at competitive price from our factory.

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