Study On The Electric Properties Of Polyvinyl-butyral Magnetoelectric Composites

The magnetoelectric composites have received continuous attention due to their multifunctionality and important application in transducers, actuators and other sensors. In this paper, three-phase magnetoelectric composites and laminate magnetoelectric composites consisting of polyvinyl-butyral (PVB), Tb-Dy-Fe alloy (Terfenol-D), and lead zirconate titanates (PZT), prepared by using a melt blending and hot-molding technique. The composites are based on the simple combination of Terfenol-D and PZT particles which are mixed and embedded in the polymer matrix, and on the simple realization of coupling interaction between magnetostriction and piezoelectricity. And the dielectric properties, piezoelectric properties and magnetoelectric effect of composites were well researched.The PVB/PZT composites were prepared to confirm the optimized volume fraction of PVB in magnetoelectric composites. The dielectric and piezoelectric measurement results show that the effective dielectric constant and piezoelectric constant were found to decrease with increasing volume fraction of PVB (/pvb)-Scanning electron microscope shows that PVB has excellent adhesive effect on PZT. When f_PVB is 0.15, the maximum dielectric constant and piezoelectric constant for PVB/PZT composites was 150 and 47pC/N, respectively. When f_PVB>0.5, dielectric and piezoelectric properties of the PVB/PZT composites abruptly decrease. A small quantity of carbon was filled in PVB/PZT composites to enhance the piezoelectric properties of PVB/PZT composites. The results show that the piezoelectric properties of PVB/PZT composites increased as the adding of carbon. The composites possessed better quality and properties when f₍PVB is in range of 0.2-0.3, therefore, f₍PVB is 0.3 was employed as a matrix for further investigation on the magnetoelectric effect.A three-phase magnetoelectric composites consisting of PVB, Terfenol-D and PZT particles were fabricated using a melt blending and hot-molding technique. And the volume fraction of PVB was fixed as 0.3 according to past research, and the volume fraction of Terfenol-D, f_Terfenol-D changed at 0.01-0.06. The results indicated that the dielectric constant, piezoelectric constant and magnetoelectric properties of PVB/PZT/Terfenol-D composites increased with increasing f_Terfenol-D, and the highest ME voltage coefficient (dE/dH)₃₃ of 720 mV / cm· Oe was observed at the resonacefrequency of 100kHz and a magnetic field of 4000Oe when ./rerfenoi-D is 0.04. If /rerfenoi-D>0.04, the composites can not be polarized, thus the piezoelectric property of the composites reduced, and the magnetoelectric effect declines with increasing/Terfenol-D.To eliminate the limitation in three-phase PVB/PZT/Terfenol-D composites, the laminates composites consisting of PVB/PZT/CB layers and PVB/Terfenol-D layers were prepared. The results show that volume fraction of Terfenol-D increased in laminate composites, consequently the magnetoelectric properties improved. The best ME voltage coefficient(dEldH)n of 1800mVIcm Oe is observed at 110 kHz and 4000Oe for the sample with PVB/Terfenol-D layer of 0.5mm in thickness (/rerfenoi-D is 0.17).