플라스틱 자석 혼합물의 균질도 평가방법과 균질도가 자기특성에 미치는 영향

다국어 초록 (Multilingual Abstract)

Homogeneous feedstock is necessary to make plastic magnets with uniform magnetic properties, therefore the optimized mixing route and the homogeneity evaluation method are demanded. In this paper, method of homogeneity evaluation and effect of homogeneity on the magnetic properties were investigated using Srferrite /EVA plastic magnets. The feedstocks with different homogeneity were prepared using batch mixer and single screw extruder. The homogeneities of feedstocks were tested by torque sensor, capillary rheometer, and measurement of magnetic properties. Mixing torque measurement using torque sensor was an effective method to determine the critical powder loading, but it was not suitable to determine the feedstock mixing quality. Particle alignment measurement of a plastic magnet was very accurate to evaluate the homogeneity, but expensive equipments were required to make and measure the samples. Pressure measurement using capillary rheometer was a very effective and easy method with high accuracy. Homogeneous feedstock increased the particle alignment of plastic magnet. Remanent flux density and maximum energy product increased linearly and quadratically with increasing particle alignment, respectively.