KSEF R&D Excellence: Study of Sm-Co Magnets Produced Using Novel Compaction Techniques in Powder Metallurgy

The aims of the proposed project are to develop a new technique to quantify particle size distribution ofSmCos powders and to apply cyclic loading to compaction of the SmCos powders, with a view to optimization of the processing procedure by understanding the metallurgical principles in SmCos production in order to improve the magnetic performance and quality consistency of the SmCos products. The specific points are: . To develop a new technique to quantify the size distribution of SmCos. The Sm-Co alloy powders will be mixed with pure Cu powders using a ball milling machine to separate SmCos particles from being in contact with each other. The weU mixed powders will be compacted and then made for metallographic observations on SEM to quantify the particle size distribution statistically. Surfactants will also be tried to disperse SmCos particles for particle size distribution measurements. . To study the effects of size distribution of SmCos particles on the density of a compact and the magnetic and mechanical properties of the sintered SmCos' magnets. The factors that affect the particle distribution and shape will be investigated. . To apply cyclic loading, instead of a conventional static loading, to packing and compacting Sm-Co powders in an applied magnetic field, in an atteQ1ptto improve the level of particle alignment in the magnetic field, increase the density and reduce the density gradient of the compacted powders. A high power ultrasonic vibration device will also be used to increase the packing density and the level of particle alignment of the powders. This method has never been used in powder compaction before. . Microstructures (grain, magnetic domain and porosities) of the sintered Sm-Co alloys will be examined using SEM and optical microscopy to understand the mechanism for any possible changes in the magnetic and mechanical properties of the alloys produced under different processing conditions. Texture in these samples will also be measured using either an X-ray diffraction or an electron back scatter diffraction to evaluate the level of particle alignment in the samples. . To characterize the magnetic properties using a vibratiq.g sample magnetometer including determination of intrinsic coercivity Rei. remnant magnetization, maximum energy product and Curie temperature. .