Lead-Free Piezoelectric Composition for Actuators
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Solution Overview
Problem
Lead-based piezoelectric compositions pose environmental concerns due to high lead volatility, and existing lead-free alternatives, such as bismuth sodium titanate, suffer from low spontaneous polarization and high power consumption, limiting their practicality and efficiency in applications like actuators and sensors.
Innovation Solution
A bismuth sodium titanate-based piezoelectric composition with a specific perovskite-typed structure, characterized by the formula (Bi(0.5x+y+z)Na0.5x)m(Tix+0.5yMg0.5yAlz)O3, where 0.01≦x≦0.8, 0.2≦y≦0.8, 0.01≦z≦0.6, and 0.75≦m≦1.0, is developed to enhance spontaneous polarization and electric resistivity, reducing power consumption and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-based piezoelectric compositions are used, then piezoelectric properties are improved, but environmental harm increases due to lead volatility
Solution Approach 1:
The patent changes the chemical composition parameters by replacing lead-based compounds with bismuth-based compounds (Bi0.5Na0.5)TiO3 and Bi(Mg0.5Ti0.5)O3 in specific ratios, thereby eliminating lead while maintaining piezoelectric functionality through compositional optimization
Solution Approach 2:
The patent creates a composite piezoelectric material combining multiple bismuth-based perovskite phases with specific stoichiometric ratios, forming a new composite system that achieves both environmental compatibility and functional performance
2Object-affected harmful factors
If bismuth sodium titanate is used as lead-free alternative, then environmental friendliness is improved, but piezoelectric performance deteriorates due to low spontaneous polarization
Solution Approach 1:
The patent combines (Bi0.5Na0.5)TiO3 with Bi(Mg0.5Ti0.5)O3 in a composite structure, where the interaction between different bismuth-based phases enhances spontaneous polarization beyond what single-phase bismuth sodium titanate can achieve
Solution Approach 2:
The patent optimizes the stoichiometric parameters x, y, and z in the composite formula to control the ratio of different bismuth-based phases, thereby tuning the spontaneous polarization to desired levels while maintaining environmental compatibility
3Object-affected harmful factors
If bismuth sodium titanate is used, then lead-free composition is achieved, but power consumption increases due to low electric resistivity
Solution Approach 1:
The composite structure of bismuth-based perovskites with optimized phase ratios reduces leakage currents and improves electric resistivity, thereby lowering power consumption in actuator applications while maintaining the lead-free advantage
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 improved composition achieves higher spontaneous polarization and electric resistivity, enabling efficient power use in actuators and sensitive performance in sensors, while being environmentally friendly by eliminating lead usage.
Implementation Method 1
A piezoelectric element with a piezoelectric composition used therein will deform when an electric field is externally applied and can generate electric charges on the surface when it receives an external stress
Implementation Method 2
the piezoelectric properties are desired to be further improved. Further, in the case of Bi(Me0.5E0.5)O3 based materials, a technical problem that a high insulation property can not achieved will arise
Data Source
AI summary
The present invention aims to provide an excellent piezoelectric composition and an excellent piezoelectric element if the piezoelectric properties especially a high spontaneous polarization and a sufficiently high resistivity, the low pollution, the environment and the ecology are considered. In the piezoelectric composition, the main component contains the substance represented by the following formula with a perovskite-typed structure, (Bi(0.5x+y+z)Na0.5x)m(Tix+0.5yMg0.5yAlz)O3. Wherein, 0.01≦x≦0.8, 0.2≦y≦0.8, 0.01≦z≦0.6, 0.75≦m≦1.0, and x+y+z=1.