Custom ferrite round magnet manufacturing factory

The sintering process is discussed, and how to treat the hard brittleness by special machining to adapt to different shape requirements, such as circle and cake shape.
Ferrite magnets, with their unique physical and chemical properties, play an indispensable role in many industrial applications. In particular, the ferrite round magnet, because it is widely used in motors, speakers, sensors and other equipment, its manufacturing process is particularly important. This article will delve into the sintering process of ferrite round magnets and its special machining technology, and reveal how to convert these hard and brittle magnetic materials into ferrite round magnets that meet various design requirements.
Initial raw material and mix
The manufacture of ferrite round magnets begins with carefully selected raw materials, mainly consisting of iron oxide (Fe2O3), barium carbonate (BaCO3) or strontium carbonate (SrCO3), and sometimes other additives are added to improve magnetic properties or processing characteristics. After the raw material is accurately weighed, it enters the powder mixing stage. This step can be done either dry or wet, and wet mixing usually involves mixing the raw material with a binder to form a paste, followed by spray drying or extrusion molding to form a uniform particle. Dry mixing is performed directly under mechanical grinding conditions and is suitable for powders that do not require additional binders.
Granulation and pre-sintering
Granulation is the conversion of the mixed powder into a more manageable particle, a step that is crucial for subsequent molding. Wet granulation uses a liquid binder to help form particles, while dry granulation relies on physical pressure or vibration and sometimes requires preheating to promote bonding between particles. After granulation is complete, the particles undergo pre-sintering, an initial heating process designed to remove residual moisture and promote the initial reaction of the raw material, laying the foundation for the final sintering of the ferrite round magnet.
sintering
Sintering is a key step in the manufacture of ferrite round magnets, which determines the final physical and magnetic properties of the magnet. In this high-temperature process, the pre-sintered particles fuse with each other without a liquid phase to form a dense magnet. The sintering temperature is usually between 1000°C and 1300°C, adjusted according to the formulation and the desired properties. By precisely controlling the sintering conditions, the microstructure of the magnet can be optimized to obtain the ideal magnetic properties.
Special machining
The hard brittleness of ferrite magnets is a challenge in their processing. In order to process the sintered magnets into rings, special machining techniques are required. Since direct cutting or drilling can cause cracks or debris, manufacturers typically employ the following strategies:
Precision grinding: The use of diamond grinding wheels for grinding, because ferrite is an insulating material, metal tools are not suitable. Grinding technology enables high precision dimensional requirements while reducing material loss.
Stamping and mold forming: In some cases, especially in the production of small or medium-sized ferrite round magnets, the mold is pressed before sintering to form a green blank that approximates the final shape, reducing the complexity of post-processing.
Laser or water jet cutting: For magnets with complex shapes or requiring extremely high precision, laser or water jet cutting technology provides a non-contact processing method that reduces thermal damage and stress concentration of the material and is suitable for handling hard and brittle materials.
Surface treatment and post-treatment
After processing, in order to improve durability and aesthetics, ferrite round magnets may need to be surface treated. This includes plating (such as nickel, zinc or gold) to enhance corrosion resistance, or polishing to improve surface finish. In addition, the magnetization direction of the magnet also needs to be set in a specific magnetic field to ensure its performance in the application.
conclusion
The manufacture of ferrite round magnets is a complex and delicate process, from the selection of raw materials to the final machining, each step is crucial to the performance of ferrite round magnets. Through the precise control of the sintering process and the clever treatment of hard brittleness, manufacturers are able to produce products that meet the shape requirements and have great magnetic properties.