Lead-Free Piezoelectric Precursor Solution for Stable Sol-Gel Processing
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Solution Overview
Problem
Current lead-free piezoelectric materials face challenges in achieving high piezoelectric coefficients while avoiding toxic solvents and ensuring environmental safety, as they often require complex preparation methods and may not maintain stability in sol solutions.
Innovation Solution
A precursor solution for BZT-BCT ceramics is developed using anhydrous metal precursor compounds, polyols, carboxylic acids, and chelating agents, which form a clear and stable sol solution without gelling, allowing for the production of piezoelectric materials with high piezoelectric coefficients without using carcinogenic or mutagenic solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional sol-gel methods are used to prepare lead-free piezoelectric materials, then the preparation process is simplified, but the sol solutions tend to gel and precipitate, reducing stability
Solution Approach 1:
The patent changes the chemical parameters of the sol solution by using anhydrous metal precursor compounds and specific chelating agents in controlled molar ratios. This parameter modification prevents unwanted gelation and precipitation while maintaining solution stability during storage and processing
Solution Approach 2:
The patent introduces chelating agents as intermediary substances that mediate between the metal precursor compounds and the solvent system. These chelating agents form stable complexes with metal ions, preventing premature precipitation and controlling the sol-gel transition, thus enhancing solution stability
2Reliability
If toxic solvents are used in the preparation of piezoelectric materials, then the piezoelectric coefficients can be enhanced, but environmental safety and human health are compromised
Solution Approach 1:
The patent replaces toxic solvents with non-toxic alternatives (polyols, carboxylic acids, esters, ketones, ethers), converting a harmful preparation process into a safe one. The invention demonstrates that environmentally friendly solvents can achieve the same or better piezoelectric performance without compromising material quality
Solution Approach 2:
The patent modifies the chemical composition parameters by selecting specific non-toxic solvent classes and controlling their ratios with chelating agents and metal precursors. This parameter optimization ensures high piezoelectric coefficients are achieved using only environmentally safe materials
3Reliability
If complex preparation methods are used to achieve high piezoelectric coefficients, then the piezoelectric performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent segments the preparation process into distinct functional components: anhydrous metal precursor compounds, chelating agents, and non-toxic solvents. Each component performs a specific function, and their controlled combination simplifies the overall process while achieving high piezoelectric coefficients
Solution Approach 2:
The patent optimizes key preparation parameters including the anhydrous nature of precursors, molar ratios of chelating agents to metals, and solvent composition. These parameter changes enable high-performance materials to be produced through a simplified, more controllable preparation process
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 enables the production of lead-free piezoelectric materials with high piezoelectric coefficients, comparable to PZT, while ensuring environmental safety and simplifying the preparation process, resulting in stable and efficient piezoelectric films and powders for various applications.
Implementation Method 1
a chelating agent
Implementation Method 2
The sol-gel technique consists in mixing metal-organic compounds (principally metal alkoxides) in an organic solvent. The subsequent addition of water generates two reactions: one of hydrolysis, and one of condensation.
Implementation Method 3
The subsequent addition of water generates two reactions: one of hydrolysis, and one of condensation.
Implementation Method 4
Piezoelectric materials are materials that are able to expand or contract when a voltage is applied (electrostrain effect), and conversely to generate a voltage if they are subjected to a pressure (piezoelectric effect).
Data Source
AI summary
The present disclosure relates to a precursor solution for the preparation of a ceramic of the BZT-αBXT type, where X is selected from Ca, Sn, Mn, and Nb, and α is a molar fraction selected in the range between 0.10 and 0.90, said solution comprising: 1) at least one barium precursor compound; 2) a precursor compound selected from the group consisting of at least one calcium compound, at least one tin compound, at least one manganese compound, and at least one niobium compound; 3) at least one anhydrous precursor compound of zirconium; 4) at least one anhydrous precursor compound of titanium; 5) a solvent selected from the group consisting of a polyol and mixtures of a polyol and a secondary solvent selected from the group consisting of alcohols, carboxylic acids, esters, ketones, ethers, and mixtures thereof; and 6) a chelating agent, as well as method of using the same.