CN-117682851-B - Lead-free piezoelectric ceramic material for collecting high-temperature energy at temperature of 250 ℃ and preparation method thereof

Abstract

A leadless piezoelectric ceramic material capable of being applied to high-temperature energy collection at 250 ℃ and a preparation thereof belong to the field of piezoelectric ceramic materials. The ceramic material has a matrix chemical composition Bi 1.02 FeO 3 -BaTiO 3 -x mol％MnO 2 , wherein x has a value of 0.0-0.5, and a material system with x having a value of 0.2 is preferable. And (3) mixing according to the corresponding metering ratio, and preparing a sample by adopting the steps of wet grinding, drying, granulating, compression molding and sintering. The invention realizes that the lead-free piezoelectric ceramic has excellent power generation characteristic at the high temperature of 250 ℃, and has great propulsion effect on the piezoelectric energy collection technology industry.

Inventors

• HOU YUDONG
• Guo Jianzhe
• Xi Kaibiao
• ZHU MANKANG
• ZHENG MUPENG

Assignees

• 北京工业大学

Dates

Publication Date

20260512

Application Date

20231212

Claims (3)

1. 1. The leadless piezoelectric ceramic material for 250 ℃ high temperature energy collection is characterized in that the matrix chemical composition of the leadless piezoelectric ceramic material is 0.70Bi 1.02 FeO 3 -0.30BaTiO 3 -x mol% MnO 2 , wherein the numerical value of x is 0.1-0.5; the preparation method of the leadless piezoelectric ceramic material comprises the following steps: (1) Weighing raw materials Bi 2 O 3 、Fe 2 O 3 、BaCO 3 、TiO 2 and MnO 2 according to the molar ratio of elements in the chemical formula 0.70Bi 1.02 FeO 3 -0.30BaTiO 3 -x mol% MnO 2 , wherein the numerical value of x is 0.1-0.5; (2) Placing the weighed raw materials into a ball milling tank, and ball milling for 24 hours in a horizontal mill by taking absolute ethyl alcohol as a medium, drying slurry obtained after ball milling, calcining dried powder at 800 ℃ for 3 hours, and cooling along with a furnace; (3) Carrying out secondary ball milling and drying on the powder cooled in the step (2), grinding the dried powder, granulating by adopting PVA (polyvinyl alcohol), and granulating by adopting a polyvinyl alcohol aqueous solution with the mass concentration of 5% as a binder; (4) And (3) standing the powder obtained by granulating in the step (3), performing compression molding to obtain a green body, performing glue discharging treatment, finally sintering at 980-1000 ℃, preserving heat for 3 hours, and cooling to room temperature along with a furnace to obtain the target material.
2. 2. The lead-free piezoelectric ceramic material according to claim 1, wherein the material system having x value of 0.2 has excellent energy collecting performance at 250 ℃ with a transduction coefficient d×g=4905×10 -15 m 2 /N, a high depolarization temperature T d ≡ 250 ℃, an insulation resistivity ρ >10 7 Ω·cm at 250 ℃, and a power density P 250 ℃ ＝5.83 μW/cm 3 .
3. 3. The lead-free piezoelectric ceramic material according to claim 1, wherein the binder is used in an amount of 1 ml binder per 10g of ceramic powder.

Description

Lead-free piezoelectric ceramic material for collecting high-temperature energy at temperature of 250 ℃ and preparation method thereof Technical Field The invention belongs to the field of piezoelectric ceramic materials, and particularly relates to a lead-free piezoelectric ceramic material for collecting high-temperature energy at 250 ℃ and a preparation method thereof. Background Piezoelectric energy collectors (Piezoelectric ENERGY HARVESTER, abbreviated as PEH) with piezoelectric ceramics as cores are used as substitutes or supplements of traditional fossil energy, are widely applied to the high-tech fields of aerospace, electric automobiles and the like, and achieve the purpose of hierarchical power supply for wireless sensors. The operating environment temperature of wireless sensors in these fields is generally higher than 200 ℃, which presents a great challenge for the temperature adaptability of piezoelectric ceramics. Currently, biScO 3-PbTiO3 (BS-PT) lead-based perovskite piezoelectric materials which are dominant in the high-temperature piezoelectric market are widely applied to high-temperature PEH because of the high-temperature piezoelectric activity and high-temperature stability. However, such lead-containing based materials have a bad influence on the natural environment and the health of the human body, and are severely limited by the national environmental laws. In addition, lead-free bismuth lamellar compounds, despite having an extremely high curie temperature (T C), have poor piezoelectric properties due to their inherent two-dimensional polarization configuration, and do not provide sufficient electrical energy as PEH. The novel lead-free piezoelectric ceramic BiFeO 3-BaTiO3 (BF-BT) is considered to be a lead-free ceramic system which is most likely to replace lead-based ceramics in a high temperature region for energy collection due to the ultrahigh Curie temperature and high piezoelectric activity. For high temperature piezoelectric energy harvesting materials with high electromechanical conversion capability, first a high energy density (u) is required, expressed as: wherein d×g is the transduction coefficient of the piezoelectric ceramic, a is the stress area of the piezoelectric ceramic, and F is the external excitation force. And g is closely related to d and dielectric constant ε r, which can be expressed as: wherein ε 0 is the vacuum dielectric constant and ε r is the relative dielectric constant. As is clear from equations (1) and (2), a high piezoelectric constant and a low dielectric constant are advantageous for the improvement of energy density. Considering that the high temperature piezoelectric energy collector is subjected to the impact of temperature change in the practical application process, the ceramic is required to have an extremely high depolarization temperature (T d) so as to ensure that the PEH can keep the stability of piezoelectric performance at a higher temperature. In addition, the insulation resistivity of the ceramic is greatly reduced due to the activation of oxygen vacancies at high temperature, and the resistivity must be maintained above 10 7 Ω·cm during application. If the amount is less than this range, the generated charge is difficult to be captured by the electrode, and an output current cannot be formed, which is often neglected in the conventional studies. In the invention, 0.70Bi 1.02FeO3-0.30BaTiO3 prepared by an excessive Bi compensation method is taken as a matrix, mn element doping is introduced, and a 0.70Bi 1.02FeO3-0.30BaTiO3-x mol％MnO2 (BF-BT-xMn for short) high-temperature piezoelectric ceramic material system is constructed. The optimal BF-BT-xMn sample has high transduction coefficient, high depolarization temperature and high insulation resistivity at the temperature of 250 ℃, meets the requirement of high-temperature energy collection, and fills the blank of stable power generation of lead-free piezoelectric ceramics at the temperature of 250 ℃. So far, the excellent transduction coefficient and the lead-free material applied at high temperature of the system of the patent are not reported. Disclosure of Invention The invention aims to provide a lead-free piezoelectric ceramic material applicable to a high-temperature piezoelectric energy collector and a preparation method thereof. The power generation characteristics of the cantilever beam type energy collector at the high temperature of 250 ℃ are characterized by the cantilever beam type energy collector. In order to achieve good energy collection performance at high temperature, the invention promotes the increase of the transduction coefficient and improves the depolarization temperature of the ceramic by introducing excessive bismuth element and Mn element doping, and meanwhile, the Mn element doping and the bismuth element excessive greatly improve the high-temperature insulation resistivity of the ceramic and solve the problem of leakage of the ceramic at 250 ℃. By co