Lightweight thermoplastic coated soft magnetic composites (SMC) and application for high-efficiency brushless DC motors

Abstract

The introduction of new materials and manufacturing technologies has significantly improved soft magnetic composites (SMCs) applications, with unique 3D shapes, reduced weight, and lower energy losses, material waste, and manufacturing costs. However, coating materials and existing iron powder insulation techniques limit the applicability of SMCs. This study used an organic polyether ether ketone (PEEK) coating to insulate iron particles using a more effective technique. The prepared SMCs comprised several volume concentrations of iron and PEEK, which were evaluated based on their magnetic, electric, and physical properties. Their magnetic properties were studied at various temperature ranges, considering the operating temperature limits for different applications. A mass magnetization saturation value of 236.2 emu/g was achieved at 348.15 K for a 6.2 g/cm3 sample. Furthermore, lighter and energy-efficient brushless direct current (BLDC) motors featuring SMC cores were manufactured and compared with a laminated core-based motor. The developed SMC motors (93 %) were approximately 9.90 % more efficient than the laminated core-based motors (83.1 %), while the core losses of SMC core (<1 %) were approximately 5.50 % less than those of the laminated core (6.50 %).