Lead-Free Piezoelectric Material Temperature Stability
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Solution Overview
Problem
Current lead-free piezoelectric materials face challenges in maintaining remarkable piezoelectric and dielectric characteristics across a wide temperature range due to the inclination of the Morphotropic Phase Boundary (MPB) line in their phase diagrams, leading to temperature-dependent performance issues.
Innovation Solution
A piezoelectric material composed of a rhombohedral and a tetragonal/orthorhedral crystal with a perovskite structure, where the Curie temperatures of the two components differ by no more than 50°C, positioned near the MPB line in a phase diagram, ensuring stability and high Curie temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a lead-free piezoelectric material is used to reduce environmental impact, then environmental friendliness is improved, but the material fails to maintain remarkable piezoelectric and dielectric characteristics across a wide temperature range
Solution Approach 1:
The invention uses a composite piezoelectric material system comprising multiple perovskite-type compounds (such as Pb(Zr,Ti)O3, Pb1-xLaxZr1-yTiyO3, or Pb1-xLaxZr1-yTiO3) with different Curie temperatures. These compounds are combined in specific ratios to create a composite material that maintains stable piezoelectric and dielectric characteristics across a wide temperature range while being lead-free, thus resolving the contradiction between environmental friendliness and temperature stability.
2Temperature
If the Curie temperature is increased to expand the usable temperature range, then temperature range is improved, but the piezoelectric characteristic deteriorates due to the inverse relationship between Curie temperature and piezoelectric performance
Solution Approach 1:
The invention changes the parameters of the piezoelectric material system by combining multiple compounds with different Curie temperatures (Tc1, Tc2, Tc3) in specific ratios. This parameter adjustment allows the composite material to exhibit stable piezoelectric characteristics across a wide temperature range, resolving the inverse relationship between Curie temperature and piezoelectric performance by distributing the temperature response across multiple components.
3Device complexity
If a single piezoelectric material composition is used to simplify the material system, then device complexity is reduced, but the material cannot maintain stable characteristics when environmental temperature changes
Solution Approach 1:
The invention employs a composite material system consisting of multiple perovskite-type compounds with different Curie temperatures combined in specific ratios. This composite approach maintains stable piezoelectric and dielectric characteristics across wide temperature ranges while avoiding the need for complex multi-layer structures or multiple discrete components, thus achieving temperature stability without excessive complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides a lead-free piezoelectric material with enhanced piezoelectric and dielectric characteristics across a wide temperature range, maintaining high Curie temperatures and reducing environmental impact.
Implementation Method 1
A piezoelectric material, which is used as a piezoelectric layer (piezoelectric ceramics) constituting a piezoelectric element, or the like mounted in various devices such as actuators, ultrasonic devices
Implementation Method 2
Curie temperature is set to be Tc1 and a second component that is a crystal other than a rhombohedral crystal in a single composition and that is configured to have a complex oxide with the perovskite structure and Curie temperature is set to be Tc2
Data Source
AI summary
A piezoelectric material contains a first component that is a rhombohedral crystal that is configured to have a complex oxide with a perovskite structure and Curie temperature Tc1 and a second component that is a crystal other than a rhombohedral crystal that is configured to have a complex oxide with the perovskite structure and Curie temperature Tc2, in which |Tc1−Tc2| is equal to or less than 50° C.