Magnetostrictive properties of carbon fiber filled polypropylene composites

Carbon fiber (CF) was surface treated and then added to polypropylene (PP) to prepare composites. The magnetostrictive properties of the composites were investigated and the following phenomena were observed. Firstly, magnetostriction as large as 1163 ppm was obtained in a magnetic field of 800 kA m−1. Secondly, the magnetostriction is dependent on the magnetic field and time interval. With a constant magnetic field, the magnetostriction first increases linearly with time and then reaches a saturation level after an interval defined as the saturation time. On the other hand, for a given time interval the magnetostriction increases with magnetic field. Thirdly, with the magnetic field set to 0, the magnetostriction decreases continuously from the saturation value to zero over a considerable time. Finally, the magnetostrictive properties have a hysteresis effect, which is different from that of TbxDy1−xFe2−y, the typical inorganic magnetostrictive material.