Lead-Free Piezoelectric Ceramic Composition for High-Temperature Stability
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Solution Overview
Problem
Current lead-free piezoelectric ceramics face challenges with low Curie temperature, depolarization under high temperatures, and poor mechanical quality factors, limiting their effectiveness in a wide temperature range and durability.
Innovation Solution
A lead-free piezoelectric ceramic composition with a perovskite metal oxide formula (Ba1-xCax)(Ti1-yZr)yO3, incorporating Mn as a primary auxiliary component and Cu, B, or Si as secondary auxiliary components, optimized to maintain high piezoelectric constants and mechanical quality factors across a broad temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If barium titanate-based lead-free piezoelectric ceramic is used, then environmental compatibility is improved, but Curie temperature is reduced to 80°C or less causing depolarization under high-temperature environment
Solution Approach 1:
The invention changes the compositional parameters by substituting specific elements (Ta, Nb, W at B-site; La, Nd, Sm at A-site) in controlled amounts to raise the Curie temperature from 80°C to 120°C or higher while maintaining lead-free composition, thus resolving the contradiction between environmental compatibility and high-temperature stability
Solution Approach 2:
The invention creates a composite piezoelectric ceramic system combining multiple elements (Ba, Ca, La, Nd, Sm at A-site; Ti, Zr, Ta, Nb, W at B-site) to achieve synergistic effects that simultaneously provide lead-free composition, high Curie temperature, and good piezoelectric properties
2Object-affected harmful factors
If barium titanate-based lead-free piezoelectric ceramic is used, then environmental compatibility is improved, but mechanical quality factor is reduced causing heat generation and depolarization under alternating voltage
Solution Approach 1:
The invention optimizes compositional parameters by controlling the amounts of Ca (0.05-0.20), Ta (0.02-0.10), Nb (0.02-0.10), and W (0.02-0.10) to achieve a mechanical quality factor of 400 or higher, thus resolving the contradiction between environmental compatibility and reliability under alternating voltage
Solution Approach 2:
The invention develops a multi-element composite ceramic system that combines the benefits of different elements to simultaneously achieve lead-free composition, high mechanical quality factor, and resistance to heat generation under alternating voltage conditions
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 provides a lead-free piezoelectric ceramic with stable piezoelectric properties and mechanical quality factors, ensuring durability and performance in a wide temperature range, suitable for various applications including liquid discharge heads, ultrasonic motors, and optical apparatuses.
Implementation Method 1
piezoelectric ceramic having a main component and auxiliary components, and a method for manufacturing the piezoelectric ceramic
Data Source
Figure 1
Figure 2A~2b
Figure 3A~3B
AI summary
A piezoelectric ceramic contains a main component, Mn as a first auxiliary component, and a second auxiliary component containing at least one element selected from the group consisting of Cu, B, and Si. The main component contains a perovskite metal oxide having the following general formula (1): (Ba1-xCax)a(Ti1-yZry)O3 (0.100 <= x <= 0.145, 0.010 <= y <= 0.039) (1) The amount b (mol) of Mn per mole of the metal oxide is in the range of 0.0048 <= b <= 0.0400, the second auxiliary component content on a metal basis is 0.001 parts by weight or more and 4.000 parts by weight or less per 100 parts by weight of the metal oxide, and the value a of the general formula (1) is in the range of 0.9925 + b <= a <= 1.0025 + b.