Solid-state Synthesis and High Magnetostriction Performances of Heavy Rare Earth-Free Sm0.88Nd0.12Fex Particulate Composites

The magnetostrictive materials are widely applied as modern smart materials converting electrical to mechanical energy. Here, the pseudobinary Sm0.88Nd0.12Fex compounds, free of both (expensive) heavy rare earths and B/Co stabilizer, have been prepared with mechanical alloying and subsequent solid-state sintering process. An amorphous phase can be formed by high-energy ball milling, followed by the formation of single-phase Sm0.88Nd0.12Fe1.80 alloy at an annealing temperature of 690 degrees C. A high anisotropic magnetostriction lambda(a) as large as 1280 ppm for the as-sintered alloy is obtained at an external field of 12 kOe. The oriented pseudo 1-3 type particulate composite is fabricated by embedding and aligning the as-sintered alloy particles in an epoxy matrix under an oriented magnetic field. The composite with a volume faction of 30% shows large magnetostriction (lambda(a) similar to 895 ppm at 12 kOe). In particular, lambda(a) and the longitudinal magnetostriction lambda(||) at a low field (3 kOe) reaches a value as high as 630 and 450 ppm, respectively, 78% and 84% larger than that of its as-sintered polycrystalline alloy although V-p is only 30%. Ultimately, it is anticipated that this work will open a new design paradigm to develop Sm-based materials with negative-magnetostriction performance.