Lead-Free Piezoelectric Material Low-Temperature Sintering
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Solution Overview
Problem
Existing lead-free piezoelectric materials, such as those based on sodium niobate and barium titanate, require high sintering temperatures and incorporate cobalt, which is expensive and harmful, while also having low insulating resistance.
Innovation Solution
A piezoelectric material composed of a perovskite-type metal oxide represented by the formula (1−x){(NayBa1-z)(NbzTi1-z)O3}-xBiFeO3, where 0<x≦0.015, 0.80≦y≦0.95, and 0.85≦z≦0.95, allowing for low-temperature sintering and eliminating the use of lead, potassium, and cobalt, while enhancing insulating and piezoelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high sintering temperature (1,200°C to 1,280°C) is used to improve piezoelectric properties, then piezoelectric constant is improved, but manufacturing cost and energy consumption increase
Solution Approach 1:
The patent changes the chemical composition parameters of the piezoelectric material by incorporating bismuth ferrite (BiFeO3) into the sodium niobate-barium titanate system. This compositional modification enables the material to achieve high piezoelectric constants at lower sintering temperatures (below 1,200°C), thus resolving the contradiction between piezoelectric performance and energy consumption during manufacturing
2Reliability
If cobalt is added to improve piezoelectric constant, then piezoelectric properties are improved, but insulating resistance decreases and environmental harm increases
Solution Approach 1:
The patent extracts cobalt from the material composition entirely, replacing it with bismuth ferrite (BiFeO3) as the doping agent. This removal of cobalt eliminates the associated problems of low insulating resistance and environmental harm, while maintaining or improving piezoelectric properties through the alternative bismuth ferrite modification approach
3Reliability
If cobalt is used to enhance piezoelectric constant, then piezoelectric properties are improved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive cobalt with bismuth ferrite, which uses more abundant and cheaper elements (bismuth, iron, and oxygen). This replacement maintains the piezoelectric enhancement function while significantly reducing material costs, making the manufacturing process more economically viable
4Reliability
If lead-containing materials are used to achieve high piezoelectric performance, then piezoelectric constant is improved, but environmental harm increases
Solution Approach 1:
The patent extracts lead from the material composition, developing a lead-free piezoelectric system based on sodium niobate-barium titanate-bismuth ferrite. This extraction eliminates the environmental contamination risks associated with lead dissolution in acid rain and soil absorption, while achieving comparable or superior piezoelectric performance through the alternative compositional approach
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 material achieves a Curie temperature of 100° C. or more, improved insulating resistance, and increased piezoelectric constants, enabling its use in various applications without environmental harm.
Implementation Method 1
can be sintered at a low temperature of less than 1,200° C.
Implementation Method 2
piezoelectric material comprising a perovskite-type metal oxide
Data Source
AI summary
The present invention provides a piezoelectric material which has excellent insulating and piezoelectric properties and which contains no lead and potassium and also provides a piezoelectric element and a multilayered piezoelectric element each using the above piezoelectric material. The piezoelectric material is a perovskite-type metal oxide represented by the following general formula (1).(1−x){(NayBa1-z)(Nb7Ti1-z)O3}-xBiFeO3 (1)In the formula, 0<x≦0.015, 0.80≦y≦0.95, 0.85≦z≦0.95 are satisfied.