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CN-122010558-A - Perovskite material with wide temperature range and strong negative thermal expansion effect, and preparation method and application thereof

CN122010558ACN 122010558 ACN122010558 ACN 122010558ACN-122010558-A

Abstract

The invention provides a perovskite material with a wide temperature range and a strong negative thermal expansion effect, and a preparation method and application thereof. The perovskite material has a chemical formula of PbTiO 3‑x H 2x , wherein x is more than 0 and less than or equal to 0.15, and the average volume expansion coefficient of the perovskite material is-2.6X10 ‑5 /K to-2.50X10 ‑5 /K. The perovskite material is prepared by the steps of (1) uniformly mixing PbO, tiO 2 and TiH 2 according to a preset molar ratio to obtain a raw material mixture, loading the raw material mixture into a cylindrical crucible, placing the cylindrical crucible in a closed mold, (2) placing the closed mold filled with the raw material mixture into high-pressure synthesis equipment, respectively heating and boosting to 800-1400 ℃ and 1-30 Gpa, and maintaining for 0.5-10 hours, then respectively cooling and depressurizing to normal temperature and normal pressure, and (3) demolding and grinding the product to obtain the perovskite material. Further, the material of the present invention can be used for precision optics. The material of the invention has strong negative thermal expansion effect and wide working temperature area.

Inventors

  • PAN ZHAO
  • LONG YOUWEN

Assignees

  • 中国科学院物理研究所

Dates

Publication Date
20260512
Application Date
20260123

Claims (10)

  1. 1. A perovskite material having a broad temperature range and a strong negative thermal expansion effect, characterized in that the perovskite material has the following chemical formula: PbTiO 3-x H 2x , wherein x is more than 0 and less than or equal to 0.15; The perovskite material has an average bulk expansion coefficient of-2.6X10 -5 /K to-2.50X10 -5 /K.
  2. 2. The perovskite material with a wide temperature range and a strong negative thermal expansion effect according to claim 1, wherein the perovskite material has a tetragonal crystal structure with a space group of P4mm.
  3. 3. The perovskite material having a broad temperature range and a strong negative thermal expansion effect according to claim 1, wherein the perovskite material exhibits a negative thermal expansion effect in a temperature range of 300K to 790K.
  4. 4. The perovskite material with a broad temperature range and strong negative thermal expansion effect according to claim 1, wherein the perovskite material has an average bulk expansion coefficient of-2.52 x 10 -5 /K to-2.50 x 10 -5 /K.
  5. 5. A method of producing a perovskite material having a broad temperature range and a strong negative thermal expansion effect as claimed in any one of claims 1 to 4, said method comprising the steps of: (1) Uniformly mixing PbO, tiO 2 and TiH 2 according to a preset molar ratio to obtain a raw material mixture, loading the raw material mixture into a cylindrical crucible, and placing the cylindrical crucible into a closed mold; (2) Placing the closed mould filled with the raw material mixture into high-pressure synthesis equipment, respectively heating and boosting to 800-1400 ℃ and 1-30 Gpa ℃ and maintaining for 0.5-10 hours, and then respectively cooling and depressurizing to normal temperature and normal pressure; (3) Demolding and grinding the product to obtain the perovskite material.
  6. 6. The process according to claim 5, wherein the step (1) further comprises pretreating the raw material mixture at 300 to 500 ℃ for 0.5 to 10 hours.
  7. 7. The production method according to claim 5, wherein the rate of temperature rise in the step (2) is 10 to 250 ℃ per minute, and the rate of pressure rise is 0.01 to 0.30 Gpa per minute; Preferably, the cooling rate in the step (2) is 10-400 ℃ per minute, and the depressurization rate is 0.001-0.15 Gpa per minute.
  8. 8. The preparation method according to claim 5, wherein the molar ratio of PbO, tiO 2 and TiH 2 in the raw material mixture is 1 (1-x): x, wherein the value of x is consistent with x in the chemical formula of the perovskite material.
  9. 9. The preparation method according to claim 5, wherein the purities of PbO, tiO 2 and TiH 2 are not less than 99% by weight, and the particle sizes are not more than 200. Mu.m.
  10. 10. Use of a perovskite material having a broad temperature range and a strong negative thermal expansion effect as claimed in any one of claims 1 to 4 or a perovskite material having a broad temperature range and a strong negative thermal expansion effect as obtainable by a method as claimed in any one of claims 5 to 9 in precision optics.

Description

Perovskite material with wide temperature range and strong negative thermal expansion effect, and preparation method and application thereof Technical Field The invention belongs to the technical field of new materials. In particular, the invention relates to a perovskite material with a wide temperature range and a strong negative thermal expansion effect, and a preparation method and application thereof. Background Expansion and contraction of materials are ubiquitous physical phenomena. In the fields of precision machinery, electronic devices, optical systems, structural engineering and the like, mismatch of thermal expansion coefficients among elements can lead to stress concentration, performance degradation and even device failure, and is one of key problems restricting the development of high-precision and high-reliability technologies. The negative thermal expansion material has the characteristic of thermal shrinkage and cold expansion in a certain temperature range, and provides a revolutionary solution for precisely regulating and controlling the thermal expansion behavior of the composite material. By compounding the negative thermal expansion material with the conventional positive expansion material, the design of 'from zero to adjustable' of the overall thermal expansion coefficient of the material is expected to be realized. In view of the great application value, the negative thermal expansion material is listed in the national leading edge material industrialization important development guidance catalog (first batch), and becomes one of leading edge materials for important development. However, the large-scale application of negative thermal expansion materials still faces a core bottleneck that the types of the negative thermal expansion materials which are found at present are limited, and the problems that the negative thermal expansion effect is weak and the effective working temperature area is narrow are mostly existed. This results in a high precision match with a wide temperature range, full cycle, which is difficult to achieve with widely used positive expansion materials, greatly limiting their engineering applications. Among the numerous negative thermal expansion material systems, lead titanate of perovskite structure (PbTiO 3) is a classical and important type of ferroelectric material, which is of great interest because of its good ferroelectric/piezoelectric properties and inherent negative thermal expansion characteristics. The crystal structure is stable and the adjustability is high, and the performance can be regulated and controlled by various cation doping (equivalent or non-equivalent substitution of Pb or Ti positions), which provides possibility for designing novel negative thermal expansion materials. But the negative thermal expansion properties (e.g., coefficient of expansion and warm zone) of pure PbTiO 3 are not yet sufficient to meet stringent application requirements. Most of the modification studies (such as common cation doping) on PbTiO 3 tend to weaken its inherent negative thermal expansion effect or reduce its negative thermal expansion temperature region while optimizing other properties. Therefore, how to remarkably widen the working temperature area of the PbTiO 3 on the premise of maintaining or strengthening the negative thermal expansion effect becomes a technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a novel wide-temperature-zone negative thermal expansion material based on the existing PbTiO 3 -based negative thermal expansion material, which has a strong negative thermal expansion effect and also has a wide working temperature zone. It is another object of the present invention to provide a method for preparing the perovskite material having a wide temperature range and a strong negative thermal expansion effect according to the present invention, which is highly reproducible and produces a high purity sample. The above object of the present invention is achieved by a method comprising the following steps. In the context of the present invention, the term "normal temperature" means 15-30 ℃, and "normal pressure" means a pressure of about 90kPa to about 110 kPa. In the context of the present invention, the term "room temperature" refers to 25 ℃, i.e. 298K. In the context of the present invention, the working temperature zone refers to a temperature zone or negative thermal expansion temperature interval in which the negative thermal expansion material exhibits negative thermal expansion behaviour, the terms "working temperature zone" and "negative thermal expansion temperature interval" being used interchangeably. In a first aspect, the present invention provides a perovskite material having a broad temperature range and a strong negative thermal expansion effect, having the formula: PbTiO 3-xH2x, wherein x is more than 0 and less than or equal to 0.15; The perovskite material has an average bu