Preparation and magnetic properties of high performance Ca–Sr based M-type hexagonal ferrites

Abstract

In this study, the preparation and magnetic properties of Ca–Sr M-type (Ca1-x-yLaxSryFe10.9CozO19) ferrire magnets were investigated. A M-type singlephase calcined powder was synthesized with a composition of x ​= ​0.45, y ​= ​0.18 and z ​= ​0. And a very high magnetic properties of Br ​= ​5425Gauss and iHc ​= ​4602Oe were obtained by the thermal annealing and secondary fine-milling method in the sintered magnets. The magnetic properties greats exceeds that of traditional Sr–La–Co M-type ferrite, which has been the highest grade M-type hard ferrite. By use of the innovative post-processing method, the improvement could be attributed to about 4% and 0.8% increase in motor torque and motor efficiency in comparison to that of conventional process, which will eventually be used in high-efficiency motors.

Keywords

• Iron oxide powder (Fe2O3)
• Ca–Sr based
• Thermal annealing
• Secondary fine-milling
• Hard ferrite
• Motor