How do sintered ferrite magnets achieve a balance between high performance and low cost?

Sintered ferrite magnets are mainly made of SrO or BaO and Fe₂O₃ as raw materials. Among them, Fe₂O₃ is an indispensable main component, while SrO or BaO is selected according to specific performance requirements. The selection of this raw material combination has significant cost advantages. Compared with high-performance permanent magnet materials such as NdFeB, the raw materials of sintered ferrite magnets are widely available and relatively cheap. For example, Fe₂O₃ is a common oxide that is abundant in nature and easy to obtain and process. At the same time, SrO and BaO can also be obtained by refining the corresponding ores, and the cost is controllable.

In addition to the main raw materials, the use of additives and flux also affects the performance and cost of sintered ferrite magnets. The right amount of additives can improve the microstructure of the magnet and improve the magnetic properties, but too much additives will increase the cost. Therefore, in the process of raw material selection, the proportion of various raw materials needs to be precisely controlled to achieve the best balance between performance and cost.

The production process of sintered ferrite magnets is complex and delicate, and each link has an important impact on the performance and cost of the final product.

In the raw material mixing stage, it is necessary to ensure that the various raw materials are fully and evenly mixed. Uneven mixing will lead to uneven internal composition of the magnet, thus affecting the magnetic properties. In order to achieve uniform mixing, special mixing equipment is usually used, and the mixing time and mixing speed are strictly controlled.

The granulation process is to ensure the smooth progress of the solid phase reaction process. During the granulation process, the solution will be sprayed into the mixture to form a pellet material with a certain particle size. The particle size of the pellet material has an impact on the pre-burning time. A reasonable particle size distribution can improve the pre-burning efficiency and reduce production costs.

Pre-sintering is a key step in the production of sintered ferrite magnets. The purpose of pre-sintering is to make the raw materials fully react in the solid phase, and most of the raw materials are converted into ferrite phase. Optimization of the pre-sintering process can improve the deformation, shrinkage and density of the magnet and improve the magnetic properties. At the same time, a reasonable pre-sintering process can also reduce energy consumption in the subsequent sintering process and reduce production costs.

The ball milling process crushes the pre-sintered material into fine powder, and the particle size of the fine powder has an important influence on the performance of the magnet. Finer powder can improve the density and magnetic properties of the magnet, but the ball milling process will also increase energy consumption and equipment wear, thereby increasing production costs. Therefore, it is necessary to optimize the ball milling process and reduce production costs while ensuring the particle size of the powder.

The molding process divides ferrite magnets into two categories: isotropic and anisotropic, and the molding methods are also divided into wet and dry methods. Different molding processes have different effects on the performance and cost of the magnet. For example, wet molding can obtain a more uniform magnet structure, but requires the use of a large amount of water and additives, which increases production costs; dry molding has the advantages of high production efficiency and low cost, but the performance of the magnet is relatively poor. Therefore, it is necessary to select a suitable molding process based on the performance requirements and cost budget of the product.

The sintering step is a key link that affects the microstructure and magnetic properties of ferrite magnets. Unreasonable sintering parameters will cause cracks, bubbles and deformation in the magnet, reducing the magnetic properties. At the same time, the sintering process consumes a lot of energy and is an important part of the production cost. Therefore, by optimizing the sintering process, such as controlling parameters such as sintering temperature, sintering time and atmosphere, the performance of the magnet can be improved and the production cost can be reduced.

Machining is the last process in the production of sintered ferrite magnets, including grinding, polishing, cutting and punching. Since ferrite magnets are hard and brittle, special machining processes are required. For example, cutting with diamond tools can improve machining accuracy and efficiency, but it will also increase machining costs. Therefore, in the machining process, it is necessary to comprehensively consider factors such as machining accuracy, machining efficiency and cost, and select appropriate machining methods and equipment.

Sintered ferrite magnets have a series of excellent performance characteristics, which make them widely used in many fields.

In terms of magnetic properties, sintered ferrite magnets have high coercivity and large anti-demagnetization ability, which are particularly suitable for use as magnetic circuit structures under dynamic working conditions. Its magnetic energy product ranges from 1.1MGOe to 4.0MGOe. Although it is lower than some high-performance permanent magnet materials, it can meet the needs in many application scenarios.

In terms of physical properties, sintered ferrite magnets are hard and brittle, not easy to demagnetize and corrode, with simple production process and low price. Its operating temperature range is -40℃ to +200℃, which can adapt to different working environments.

According to different processing technologies, sintered ferrite magnets can be divided into isotropic and anisotropic types. Isotropic magnets have weak magnetic properties, but can be magnetized in different directions of the magnet; anisotropic magnets have strong magnetic properties, but can only be magnetized along the predetermined magnetization direction of the magnet. This characteristic allows sintered ferrite magnets to be designed and manufactured according to different application requirements.

In the field of electronic products, sintered ferrite magnets are widely used in motors, sensors, speakers, microphones, receivers and other components. Its high magnetic permeability and saturation magnetic induction intensity can effectively improve the performance of electronic products. For example, in motors, sintered ferrite magnets can provide a stable magnetic field to improve the efficiency and torque of motors; in sensors, it can achieve accurate detection of physical quantities such as magnetic field and position.

In the field of medical equipment, sintered ferrite magnets are used in medical equipment to manufacture magnetic resonance imaging equipment, medical magnets, magnetic stimulators, etc. It can generate a strong magnetic field to help doctors make accurate magnetic resonance imaging diagnoses, and can also be used to treat certain diseases.

In the field of mechanical equipment, sintered ferrite magnets are widely used in electric suction cups, electric door locks, electric permanent magnet clutches, magnetic transmissions, etc. It can provide strong magnetic force to help improve the efficiency and performance of mechanical equipment.

In the field of the automotive industry, sintered ferrite magnets are widely used in engines, brake systems, suspension systems and other components in the automotive industry. It can provide strong magnetic force to help improve the performance and safety of the car.