Preparation And Performance Analysis Of New 2-2 Piezoelectric Single Crystal Composites

Piezoelectric materials are often used to make transducers to achieve the conversion of electromechanical signals because of their characteristics of energy conversion.In recent years,ternary piezoelectric single crystal Pb(In_1/2Nb_1/2)O₃-Pb(Mg_1/3Nb_2/3)O₃-Pb Ti O₃（PIMNT）has been widely studied as a piezoelectric material with excellent performance.Compared with traditional piezoelectric ceramics and piezoelectric films,there are obvious advantages of PIMNT piezoelectric single crystals in piezoelectric and electromechanical coupling performance,but also disadvantages in acoustic matching performance and low mechanical strength.After learning the experience of piezoelectric ceramic composites,PIMNT piezoelectric single crystals and EPO-TEK301-2 epoxy resin are selected for composite,and the finite element analysis was combined with experimental preparation to prepare,test and analyze the performance of 2-2piezoelectric single crystal composites with different volume fractions,different aspect ratios and different sample thicknesses,which exhibit high electromechanical coupling performance（k_t>75%）and low-pitch impedance（Z<20 Mrayls）and achieve controllable performance by regulating the parameters of the composite material.The main research contents and conclusions are as follows:（1）Use COMSOL 5.6 to analyze the factors affecting the electromechanical coupling performance of 2-2 piezoelectric single crystal composites（single crystal volume fraction,single crystal aspect ratio and composite thickness）.The results show that the volume fraction affects the electromechanical coupling coefficient k_t of the composite,and when the volume fraction is 60%,k_t reaches the peak.The aspect ratio AR mainly affects the vibration mode of the composite material,and when AR>0.25,harmful modes such as lateral vibration mode are gradually increased.Composite thickness mainly affects the resonant and anti-resonant frequency,and the larger the thickness,the lower the frequency.（2）Prepare and test 2-2 piezoelectric single crystal composites with different volume fractions by cutting-filling method.The results show that under the condition of constant thickness and aspect ratio of the composite,with the increase of the volume fraction,the piezoelectric and electromechanical coupling performance of the composite materials show a near-linear growth state,and the acoustic matching performance decreases.（3）Prepare and test 2-2 piezoelectric single crystal composites with different aspect ratios by cutting-filling method.The results show that under the condition of constant thickness and volume fraction of the composite,the performance of the composite do not change significantly with the increase of the aspect ratio,and the pure thickness vibration mode is maintained in the range of 0.1-0.25 aspect ratio.（4）Prepare and test 2-2 piezoelectric single crystal composites with different thicknesses by cutting-filling method.The results show that under the condition of constant volume fraction,with the increase of composite thickness,the performance of the composite material changes slightly,but the resonant and anti-resonant frequency gradually decrease,which is roughly inversely proportional to the sample thickness.