What You Need to Know About the Production Process of Sintered NdFeB Magnets？

Sintered NdFeb, as a widely used high-performance permanent magnet material, its process can be divided into four main steps: raw material preparation, sintering, heat treatment and surface treatment. Let us understand the sintering Ndfeb process in more detail.

Let's begin.

Raw Material Preparation

The cornerstone of sintered NdFeB production lies in the meticulous preparation of raw materials. These primarily consist of NdFeB magnetic powder, binders, and auxiliary magnetic agents. The ratio of these components is carefully adjusted based on specific requirements to ensure that the final product meets the desired magnetic properties.

Sintering Process

Sintering, the heart of the production process, transforms the NdFeB powder into a solid material. This complex stage can be subdivided into three critical phases: pre-sintering, sintering, and cooling.

• Pre-sintering: Initiated at a low temperature, this step removes volatile compounds from the magnetic powder, resulting in the formation of a dense oxide film on the powder surface.
• Sintering: Subsequently, the powder is subjected to high temperatures, where the gaps between particles are filled, forming a compact granular structure.
• Cooling: Finally, the sintered piece undergoes gradual cooling to prevent internal stress concentrations caused by rapid temperature drops.

Heat Treatment

Heat treatment plays a pivotal role in enhancing the magnetic properties of sintered NdFeB magnets. By meticulously adjusting parameters such as temperature, duration, and atmosphere, significant improvements can be achieved in coercivity, remanence, and other key magnetic indicators. During this process, the grain structure undergoes recrystallization and alignment, leading to a notable enhancement in magnetic performance.

Surface Finishing

The final touch to the production process is surface finishing, which aims to boost the magnet's corrosion resistance and mechanical strength. Popular methods include electroplating, zinc plating, and spray coating. These treatments form a protective layer, safeguarding the magnet's integrity and enhancing its overall performance.