Manufacturing Process And Magnetic Properties Of Bonded Rare Earth-iron Giant Magnetostrictive Materials

The epoxy bonded (Sm,Dy)Fe2 and (Tb,Dy)Fe2 composites were prepared. The structure, powder size, and compressive strength of bonded SmFe2, SmoggDyo ^Fea and Tbo3Dyo7Fe2 were investigated by using X-ray diffraction-meter, scanning electro-microscope and device with pressure tester. And the dependence of magnetostriction, magnetic flux and dynamic magnetic parameter on magnetic field were measured by using multiple parameter magnetic measurement system.The matrix of bonded SmFe2 composites is a MgCu2-type structure SmFe2 phase. The dependences of the magnetostriction of epoxy bonded SmFe2 composites on binder content, model pressure and sample size were determined. The magnetostriction of samples is the maximum when the binder content is in a range of 4%-6%, and it increases with increasing the model pressure from 16 MPa to 62 MPa. The magnetostriction decreases a little with the increment of the size for rod samples.It has been found that the binder content, model pressure, particle size and solidified condition have a marked effect on the magnetostriction of epoxy Sm0 ggDy0 i2pe2 composites The magnetostriction of samples with the binder content of 4%-6%, the model pressure of 96 MPa and the particle size of 130 urn is higher than that of others. The resistivity and the compressive strength for sample have a little relation with manufacturing parameters, and the resistivity is 10000 times larger than that of samples prepared by melting method.The magnetostriction of bonded SmoggDyo i2Fe2 rod composites is 405 X 10"6 at a field of 200 kA/m. and the magneto-mechanical coupling coefficient is 0.34 at a bias field of 96 kA/m. The magnetostriction of bonded Tb03Dy07Fe2 rod composites is 580X 10"6 at a field of 200 kA/m, and the magneto-mechanical coupling coefficient is 0.40 at a bias field of 118 kA/m. It indicates that these materials are optimum cadidate for application.The magnetostriction of Terfenol-D was calculated based on the model of magnetic domain turning and the model of magnetic domain wall motion respectively. The experiment value is consistent with that of calculation in low magnetic fields.