The Design And Experiments Of Ferroelectric Tester In Multi-physical Field

Ferroelectric material is a very important functional material.Because of its unique ferroelectricity,it is widely used in many fields such as electronic information,medicine,detection,military and so on.Due to its own characteristics,ferroelectric materials are also affected by the interaction of the stress field and the temperature field in addition to the electric field.In order to ensure the long-term stability,durability and reliability of the materials'functioning,it is of great significance to deeply study the macroscopic dynamic response and the evolution laws of ferroelectric materials under multi-physical field.However,there are few ferroelectric analyzer capable of realizing multi-physical coupling in the real sense,so the development of the device is urgent.In this paper,the progress of the performance testing and analysis theory of ferroelectric materials under multi-physics coupling are reviewed and analyzed.Ferroelectric performance testing methods and the basic theory of ferroelectricity are introduced in detail.Based on this,a ferroelectric tester under mechanical-thermal-electric coupling field was developed,and a set of standard ferroelectric testing experimental procedures under multi-physical field were proposed,and a series of ferroelectric materials tests under multi-physical field were conducted,and the influence of mechanical-thermal coupling environment on the ferroelectric properties of some typical ferroelectric materials was obtained.The main research is listed below:Insulation compression fixture and silicone oil container were designed and manufactured,and the loading errors due to loading concentricity was analyzed.The ferroelectric testing module which can simultaneously measure hysteresis loop and the electrostriction curve of ferroelectric materials was built,and the test results were compared with those of a commercial ferroelectric analyzer to determine the module's high testing accuracy.A thermal loading module that can provide high temperature and low temperature environment was established with a set of thermal insulation measures increasing the thermal loading rate and the stability of the module,and the its actual effect was tested.Besides,the Insulation compression fixture was simulated and analyzed under mechanical,electric and thermal fields,respectively,guaranteeing its design feasibility theoretically.Based on the work mentioned above,the paper conducted mechanical-electric coupling,thermal-electric coupling,and mechanical-thermal-electric coupling tests on typical ferroelectric materials PZT and BTO,which obtained hysteresis loops and electrostriction curves under different compressive stress at different temperatures.Through data analysis,the following conclusions are drawn:PZT has a stable and strong ferroelectricity in the range of 25-65? under the same pressure.Stress can reduce the P_r,P_s and E_c of the material,and the appropriate compressive stress can promote the electrostrictive properties.Excessive compressive stress may reduce materials'electrostrictive properties;When higher than 65?,temperature's increase will reduce P_s and P_r,and in general,E_c and??will be at a minimum at 105?.In addition,the PZT has the strongest ferroelectricity at the temperature of 25-65?,with P_s of about 16.67?C/cm~2,P_r of about 13?C/cm2,E_c of about 580V/mm,and the??of about 165??.For BTO,the effect of compressive stress is basically to reduce P_s and P_r under constent temperature.At high pressure stress(>40.7 MPa),E_c decreases with the increase of compressive stress,while??remains essentially stable.Since BTO has two phase transition points of 5? and 120?,the change of E_c and??at lower compressive stress(<40.7MPa)is divided into three parts:at 2?,E_c increases with the compressive stress,and??decreases with the increase of compressive stress;at 5?-65?,E_c decreases with increasing compressive stress,while??increases,but at 5? and 20.3MPa,??rises abnormally;And at 105?,E_c and??are insensitive to changes of compressive stress.The effect of temperature on E_c and??is consistent:both physical parameters are at bottom when 5? and decrease with increasing temperature.The influence of temperature on P_s and P_r is also divided into three stages with phase transition:At 2?-5?,the two parameters decrease with increasing temperature under low stress,while the two parameters increase with increasing temperature under higher compressive stress;From 5? to 25?,both parameters decrease with temperature.The reason for the difference in two stages may be the phase transformation.At 25?-105?,P_s increases with temperature,and P_r reaches a maximum at 65?.