Lead-Free Piezoelectric Ceramic with Mn Doping for Stable Performance
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Solution Overview
Problem
Current lead-based piezoelectric ceramics, such as PZT, pose environmental concerns and have limitations in piezoelectric properties and mechanical quality factors, necessitating the development of lead-free alternatives with improved characteristics for wide temperature range applications.
Innovation Solution
A lead-free piezoelectric ceramic composition based on perovskite type metal oxides with specific formulations including Ba, Ca, Ti, Sn, Zr, and Mn, optimized to achieve high piezoelectric constants and mechanical quality factors across a wide temperature range, utilizing specific molar ratios and auxiliary components like Mn and Cu to enhance properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free piezoelectric ceramic is used to replace lead-based PZT, then environmental harm is reduced, but piezoelectric properties and mechanical quality factor deteriorate
Solution Approach 1:
The patent uses a composite material system with multiple elements (Ba, Ca, Ti, Sn, Zr, Mn) where Mn acts as a dopant in the perovskite structure. This composite approach allows combining the environmental benefits of lead-free materials with improved piezoelectric properties through synergistic element interactions, specifically achieving d33≥300 and Qm≥400 simultaneously
Solution Approach 2:
The patent optimizes specific compositional parameters including Mn content (0.0048-0.0400 mol per mole of metal oxide), Ca substitution ratio (x: 0.08-0.20), and stoichiometric ratio (a: 0.9925+b-1.0025+b) to achieve the target performance. By precisely controlling these parameters, the material achieves both environmental compatibility and high piezoelectric properties
2Object-affected harmful factors
If barium titanate is used as lead-free alternative, then environmental harm is reduced, but mechanical quality factor and piezoelectric property deteriorate
Solution Approach 1:
The patent introduces Mn dopants at specific local positions within the perovskite crystal structure (substituting at B-site metal positions) to locally modify properties. This localized doping creates regions with enhanced mechanical quality factor and piezoelectric response while maintaining the overall lead-free barium titanate structure, achieving Qm≥400 and d33≥300
3Strength
If Ca substitution is increased in barium titanate, then mechanical quality factor is improved, but piezoelectric property deteriorates
Solution Approach 1:
The patent optimizes the Ca substitution parameter x to a specific range (0.08-0.20) and combines it with controlled Mn doping (0.0048-0.0400 mol) to achieve the optimal balance. This precise parameter control ensures that Ca substitution provides sufficient mechanical quality factor (Qm≥400) while Mn doping compensates for piezoelectric property loss, achieving d33≥300 simultaneously
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 proposed ceramic exhibits stable piezoelectric and mechanical performance over a broad temperature range, outperforming traditional lead-containing ceramics in applications like liquid discharge heads, ultrasonic motors, and optical apparatuses.
Implementation Method 1
piezoelectric ceramic containing a perovskite type metal oxide having the following general formula (1) or (2); and Mn as a first auxiliary component
Data Source
AI summary
There is provided a piezoelectric ceramic having a high and stable piezoelectric constant and a high and stable mechanical quality factor in a wide operating temperature range, and a piezoelectric element according to the present invention includes a main component containing a perovskite type metal oxide having the following general formula (1) or (2); and Mn as a first auxiliary component,(Ba1-xCax)a(Ti1-y-zSnyZrz)O3 (1)(0.08≦x≦0.20, 0.01≦y≦0.04, 0<z≦0.04)(Ba1-xCax)a(Ti1-ySny)O3 (2)(0.08≦x≦0.20, 0.01≦y≦0.04)wherein the amount b (mol) of Mn per mole of the metal oxide is in the range of 0.0048≦b≦0.0400, and the value a of the general formula (1) or (2) is in the range of 0.9925+b≦a≦1.0025+b.