Preparation method of (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics

Abstract

The invention discloses a preparation method of (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics. The method comprises the steps of firstly weighing corresponding masses of Na2CO3, Bi2O3, SrCO3 and TiO2 according to the molar ratio to obtain a mixture; carrying out ball milling, drying and briquetting on the mixture to form a whole ingredient, sequentially carrying out pelleting and sieving on the whole ingredient to form a granulated material; pressing the granulated material to prepare a sample and sintering the prepared sample to obtain a sintered sample; and finally polishing and cleaning the sintered sample, evenly coating the front surface and the back surface of the polished and cleaned sintered sample with electrode slurry, and sintering the sample coated with a silver electrode to obtain the (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics. The (Bi<0.5>Na<0.5>)<1-x>SrxTiO3 system-based lead-free relaxor ferroelectrics obtained by the method has a high dielectric constant and obvious relaxation characteristics, is suitable for a wider temperature range, adopts a simple preparation process, is low in material cost, environmentally friendly, and becomes an excellent important candidate material used as a high-end industrial application material instead of a lead-based ceramic material in technology and economy.

Description

technical field [0001] The invention relates to the field of ceramic dielectric materials, in particular to a (Bi 0.5 Na 0.5 ) 1-x Sr x TiO 3 The preparation method of the lead-free relaxor ferroelectric system. Background technique [0002] Relaxor ferroelectrics exhibit high dielectric constants, large piezoelectric responses, strong nonlinear effects, and significant temperature and frequency dependencies. These exceptional relaxation properties are caused by the domain structure dominated by short-range order. The most important feature of relaxor ferroelectrics is that the dielectric constant has a wide range of extreme values ​​and corresponds to a relatively wide temperature position (T m ), which is different from the Curie temperature point of traditional ferroelectrics (T C ). Compared with conventional perovskite-structured ferroelectrics, this maximum value is not from the paraelectric phase transition to the long-range ordered ferroelectric phase, accomp...

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Problems solved by technology

Also, a high T m (~320°C) makes its dielectric constant have a maximum value at a higher temperature, while at room temperature the dielectric constant is much smaller than T m The dielectric constant at the place greatly limits its performance

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