High Electrical Resistivity Sm(Co,Fe,Cu,Zr)$_{\rm z}$/Sm$_{2}$S$_{3}$ Permanent Magnets With Layered Structure for Advanced Motors

Abstract

High electrical resistivity, sintered Sm(Co,Fe,Cu,Zr)z/Sm2S3 layered composite permanent magnets were fabricated by a one-step sintering process. The thickness of the Sm2S3 layers was uniform in various laminated magnet architectures and controlled between 50 and 200 μm. The dielectric Sm2S3 layer provides an enhanced electrical resistivity while the existence of an interface diffusion reaction layer between the magnet matrix and dielectric component may help to improve the mechanical properties of the laminated magnet. The Sm(Co,Fe,Cu,Zr)z/Sm2S3 magnets exhibited nearly the same magnetic properties and demagnetization curve shape as the standard non-laminated counterparts, with only a small dilution of the magnetization. These sequentially laminated Sm(Co,Fe,Cu,Zr)z/Sm2S3 magnets showed about 30 times higher electrical resistivity and good mechanical strength combined with excellent magnetic properties. The laminated Sm(Co,Fe,Cu,Zr)z magnet with 190 μ m Sm2 S3 layer thickness exhibited a remanent magnetization (Br) of 10.51 kG, an intrinsic coercivity Hci of >; 24.5 kOe and a maximum energy product of 25 MGOe.