Core-Shell Sintered Magnet With Coercivity Gradient for High Temperatures

The patent applies local quality by creating a magnet with non-uniform composition: a first region containing heavy rare earth elements (Dy, Tb) for high coercivity, and a second region with reduced or no heavy rare earth elements. This spatial differentiation of material properties allows the magnet to maintain high coercivity only where needed, reducing overall rare earth element content while preserving magnetic performance.

The magnet is segmented into distinct regions with different compositional characteristics. The first region (with heavy rare earth elements) and second region (with reduced heavy rare earth elements) are separated by a boundary, allowing independent optimization of each region's properties. This segmentation enables cost reduction by limiting expensive materials to only the necessary portion of the magnet.

The patent uses parameter changes by varying the composition parameters (heavy rare earth element content) and processing parameters (sintering temperature, holding time) to create regions with different magnetic properties. By controlling the sintering process parameters, the patent achieves selective formation of high-coercivity regions without requiring complex manufacturing techniques like selective laser melting.

The patent employs a simpler, more cost-effective sintering process compared to selective laser melting or spark plasma sintering. By using conventional sintering equipment and processes with controlled atmospheric conditions, the patent achieves the desired magnetic properties without investing in expensive specialized manufacturing equipment.