| Ferroic materials contain ferroelectric materials, ferromagnetic materials, ferroelastic materials and magnetoelectric composite materials and so on. Ferroelectric materials and magnetoelectric composite materials have been widely applied to lots of different fields such as aerospace, information storage, artificial intelligence, MEMS, wearable art equipment. When ferroic materials work in different service environment, their properties may be affected by magnetic field, electric field, force field or even more than one at the same time. Their performance could be reduced or even invalid when they worked in complex service environment. So it is important to master their performance change and failure mechanism in different service environments. In this paper, ferroelectric material Pb(Zr0.52Ti0.48)O3（PZT）, Bi3.15Nd0.85Ti3O12（BNT） and magnetic Ni were chosen as the research objects, and we studied how the preparation parameters of sol-gel preparation process of PZT, BNT ferroelectric thin films to affect their performance. At the same time, we get a series of response signals which were caused by the force field, electric field and magnetic field on the novel multifunctional bulge test system. Specific contents and results are summarized as follows,Firstly, we studied the influence of preparation parameters on PZT, BNT ferroelectric thin films and got their residual stress, elastic modulus and other parameters. The results show that: 10 layers PZT and 8 layers BNT films got their best performance when they were prepared in the oxygen atmosphere and annealed at 700 °C. The residual stress and elastic modulus of PZT and BNT films were 66.8 MPa, 99.6 MPa and 159.3 GPa, 189.0 GPa respectively by bulge test. Their elastic stiffness coefficients were15.4×1010 N/m2, 18.4×1010 N/m2 respectively and their piezoelectric coefficients both decreased with the increase of the electric field.Secondly, the variations of elastic modulus and ferroelectric properties of PZT, BNT films were studied under different electric field and oil pressure. The results are as follows, the elastic modulus of PZT increased from 159.2 GPa to 277.2 GPa when the electric field increased from 0 kV/cm to 140 kV/cm. And when the electric field was raised from 0 kV/cm to 445 kV/cm, the elastic modulus of BNT film increased from 189.0 GPa to 272.7 GPa. The bulge oil pressure made the remnant polarization and coercive field of PZT thin films added up from 22.8 μC/cm2, 137.0 kV/cm to 26.7μC/cm2, 181.0 kV/cm separately. Oil pressure made the remnant polarization of BNT film increased from 24.8 μC/cm2 to 28.3 μC/cm2. The coercive field decreased from 342.5 kV/cm to 385.0 kV/cm.Thirdly, the magnetic properties, electromagnetic coupling and force-magnetic coupling effects of PZT/Ni composite film were studied. The results are as follows, PZT/Ni composite film showed excellent hysteresis loop squareness,and its magnetic coercive field decreases after removed the binding of Si substrate. Though electromagnetic coupling effect, the electric field regulated its magnetic coercive field increased from 28.7 Oe to 38.3 Oe. Though magnetostriction effect, Oil pressure regulated the magnetic coercive field of PZT/Ni thin film from 21.7 Oe to 31.7 Oe. |
