| Multiferroic materials was a multifunction materials with two or more properties of ferroelectricity, ferromagnetism and magnetoelectric. It has extensive applications in the fields of memory, sensors, energy conversion, drives, optical devices and micro-electromechanical systems. As magnetoelectric devices have been used more widely,working environments become more complicated, the Performance and Reliability of Electromagnetic devices have been seriously affected under the interaction of strain and Electromagnetic. Besides, holes, cracks and other defects are inevitably generated due to the technical limitations of manufactural process and complex serving environment(such as temperature, humidity in multiferroic materials), which often leads to the attenuation or failure of performance. Therefore, it is necessary to study the multicoupling of multiferroic materials in complex work environments. In this paper, the multifunctional bulge test instrument was improved, and a bulge samples method with high efficiency and excellent performance was developed. The mechanical-electromagnetic properties of Pb(Zr0.52Ti0.48)O3(PZT), CoFe2O4(CFO) and Pb(Zr0.52Ti0.48)O3/CoFe2O4 were tested and analyzed. The main contents are summarized as follows:(1) A wet chemical etching method in which hydrazine was chosen as corrosive solution was developed to prepare samples for bulge test. The etching effect of hydrazine, tetraethyl ammonium hydroxide and potassium hydroxide was investigated by a lot of experiments. The results showed that hydrazine solution could corrode silicon fastly, and the corrosion rate arrived at 0.53 μm/min when the temperature was 90 ℃ and concentration was 64%. Because silicon dioxide almost has no reaction with hydrazine solution, it can be used as mask layer.Due to the fact that the solution is simple to prepare, reusable, inexpensive and less cost,hydrazine is an ideal corrosive solution for etching method. However, tetraethyl ammonium hydroxide is expensive and hard to be controled for its corrosion time and rate, while potassium hydroxide can corrode silicon dioxide faster. Therefore they are not suitable as corrosive solution.(2)The preparation and characteristics of PZT and CFO films by bulge test. Mciro structure morphologies of PZT and CFO films prepared with sol-gel process were determined by using X-ray diffraction and scanning electron microscope techniques. The results showed that the samples had smooth surfaces, inseparable structure and substantially no impurity phase formation. The novel multifunctional instrument were used to tested ferroelectrichysteresis loop under different oil pressure and pressure-deflection curve under different electric field. When the pressure was 0 KPa or maximum 60 KPa, remanent polarization of PZT thin films were 41.73 μC/cm2 and 36.02 μC/cm2, decreasing 13.6%; saturation polarization value were 64.04 μC/cm2 and 56.42 μC/cm2, decreasing 11.89%; coercive field were 228 KV / cm and 256 KV/cm, increasing 12.28%. With keeping oil pressure at 35 KPa and changing the DC voltage from 0 V to 20 V, the deflection increased from 6.5 μm to 9 μm,increasing 35.5%. The elastic modulus values increased nonlinearly as voltage increaed. The modulus was 50.9 GPa when electric field was 0 V, while it incresed to 88.58 GPa when the electric field was 5 V. Afterwards, as the electric field keeped increasing,the increment of modulus began to decrease. The modulus decreased to 60.71 GPa when electric field reached maximum 20 V.(3) The preparation and characteristics of mechanical-magneto-electrical coupling behaviors of PZT/CFO films by bulge technique. Mciro structure morphologies of PZT and CFO films prepared with sol-gel process were determined by using X-ray diffraction and scanning electron microscope techniques. The results showed that the films had smooth surfaces, uniform grain size and substantially no impurity phase formation. good electromagnetic property and obvious leakage current for interface effect and low resistance of CFO. The novel multifunctional instrument were used to tested ferroelectric hysteresis loop under different oil pressure and pressure-deflection curve under different electric field or magnetic field. When pressure was 0 KPa or maximum 60 KPa, the remnant polarization PZT/CFO were 19.19 μC/cm2 and 17.14 μC/cm2, decreasing 10.69%; saturation polarization were 26.14 μC/cm2 and 22.21 μC/cm2, decreasing 15.03%; the coercive field were 433.85KV/cm and 507.69.0 KV/cm, increasing 16.84%. Keeping the oil pressure at 46 KPa and changing the DC voltage from 0 V to 30 V, the deflection of PZT/CFO film monotonously increased from 16 μm to 11 μm, the amount of change was-45.5%. The elastic modulus were28.8 GPa and 47.2 GPa accordingly. Keeping oil pressure at 36 KPa and changing the magnetic field from 0 Oe to 850 Oe, the deflection was 5.8 μm and 4.2 μm, decreasing27.58%, while elastic modulus were 136 GPa and 254 GPa. |
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