Lead-Free BZT-BCT Precursor Solution Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sol-gel techniques for producing lead-free piezoelectric BZT-BCT materials face challenges with the use of toxic solvents like 2-methoxyethanol, leading to unstable sol solutions and environmental concerns, while existing methods for preparing precursor solutions are complex and environmentally hazardous.
Innovation Solution
A precursor solution using ethylene glycol as a solvent and acetic acid or acetylacetone as a chelating agent is developed, which stabilizes the sol solution and reduces toxicity, allowing for the production of clear and stable BZT-BCT ceramic films without carcinogenic or mutagenic compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional sol-gel techniques use toxic solvents like 2-methoxyethanol, then the sol solution becomes unstable and environmental harm increases, but replacing them with safer solvents like ethylene glycol initially results in unclear and unstable sol solutions
Solution Approach 1:
The patent introduces acetic acid or acetylacetone as chelating agents that act as intermediaries between the metal alkoxides and ethylene glycol solvent. These chelating agents form stable coordination complexes with metal ions, preventing premature precipitation and ensuring solution clarity and stability despite using the safer ethylene glycol solvent instead of toxic alternatives
Solution Approach 2:
The patent modifies the chemical parameters of the solution by controlling the molar ratios of ethylene glycol to metal alkoxides and adjusting the concentration of chelating agents. These parameter changes optimize the solubility and stability of the precursor solution, enabling the use of environmentally friendly ethylene glycol while maintaining solution homogeneity throughout the sol-gel process
2Object-generated harmful factors
If existing methods for preparing precursor solutions are used, then the process is complex and environmentally hazardous, but developing new methods increases research and development time and cost
Solution Approach 1:
The patent extracts and eliminates the environmentally hazardous components from the conventional synthesis process by replacing toxic solvents and dangerous reagents with safer alternatives. This extraction of harmful elements is achieved while maintaining the essential functionality of the sol-gel process, thereby reducing environmental hazards without requiring complete process redevelopment
Solution Approach 2:
The patent modifies key parameters of the existing synthesis methodology, such as solvent type, chelating agent concentration, and metal alkoxide ratios, to achieve environmentally friendly conditions. These parameter changes allow adaptation of established protocols rather than requiring entirely new methods, thus reducing development time while improving environmental performance
3Reliability
If lead-free BZT-BCT materials are produced using conventional methods, then piezoelectric properties can be achieved, but the use of toxic solvents and complex procedures increases environmental impact and reduces material quality
Solution Approach 1:
The patent converts the potential disadvantage of using ethylene glycol (which can form stable complexes that might prevent proper material formation) into a benefit by utilizing these complexes to ensure homogeneous distribution of metal ions. The chelating agents that initially seem to stabilize the solution too much are actually used in controlled amounts to ensure complete reaction and formation of high-quality perovskite phase with excellent piezoelectric properties
Solution Approach 2:
The patent employs a composite approach by combining ethylene glycol solvent with specific chelating agents (acetic acid or acetylacetone) in defined ratios. This composite solvent system provides both the environmental benefits of glycol-based solvents and the chemical control of chelating agents, resulting in cleaner synthesis that produces high-quality BZT-BCT materials with superior piezoelectric characteristics
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 new precursor solution method results in stable and environmentally friendly sol solutions, enabling the production of high-quality BZT-BCT ceramic films with improved piezoelectric properties, reducing environmental impact and simplifying the synthesis process.
Implementation Method 1
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
Implementation Method 2
The subsequent addition of water generates two reactions: one of hydrolysis, and one of condensation
Data Source
Figure 1a~2
Figure 3
Figure 4~5
AI summary
The present invention 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 their mixtures; and 6) a chelating agent. The invention moreover relates to a method for the preparation of the precursor solution, to a piezoelectric material obtained from the precursor solution, to a method for the preparation of a film of the piezoelectric material, to a device comprising the piezoelectric material, and to the use of the piezoelectric material.