Lead-Free Piezoelectric Material Composition for Temperature Stability
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Solution Overview
Problem
Existing lead-based piezoelectric materials have limitations such as low piezoelectric constants at high temperatures and low mechanical quality factors at low temperatures, posing environmental concerns and operational inefficiencies in devices.
Innovation Solution
A lead-free piezoelectric material with a composition of (Ba1-xCax)(Ti1-y-zSnz)O3, incorporating Mn, Bi, and Li as auxiliary components, optimized to achieve high piezoelectric constants and mechanical quality factors across a device operation temperature range of -30°C to 50°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free piezoelectric materials are used to replace lead-based materials for environmental reasons, then environmental friendliness is improved, but piezoelectric performance and mechanical quality factor deteriorate
Solution Approach 1:
The patent uses a composite material system comprising (Ba1-xCax)(Ti1-y-zSny)O3 as the base piezoelectric material, with Mn added as a dopant element. This composite approach combines multiple materials to achieve both environmental friendliness (lead-free) and high piezoelectric performance, resolving the contradiction between environmental requirements and functional performance.
Solution Approach 2:
The patent optimizes specific compositional parameters (x, y, z values in the chemical formula) to achieve peak piezoelectric performance. By precisely controlling the ratios of Ba, Ca, Ti, and Sn elements, the material achieves high piezoelectric constants and mechanical quality factors across the operating temperature range of -30°C to 50°C, maintaining reliability while being lead-free.
2Object-affected harmful factors
If barium titanate-based materials are used as lead-free alternatives, then environmental friendliness is improved, but piezoelectric constant decreases in high temperature regions
Solution Approach 1:
The patent modifies the compositional parameters of barium titanate by incorporating Ca at the A-site and Sn at the B-site of the perovskite structure. This parameter optimization ensures that the piezoelectric constant remains high across the operating temperature range of -30°C to 50°C, solving the problem of temperature-dependent performance degradation.
Solution Approach 2:
The patent introduces localized structural modifications through Mn doping and precise stoichiometric control, creating regions with enhanced piezoelectric properties that stabilize performance across temperature variations. This local quality enhancement ensures consistent high-temperature performance.
3Reliability
If Mn, Fe, or Cu is added to improve mechanical quality factor, then mechanical quality factor increases, but piezoelectric constant decreases in high temperature region
Solution Approach 1:
The patent carefully controls the concentration of Mn dopant within specific ranges (0.001 ≤ y ≤ 0.060) to achieve the optimal balance between mechanical quality factor and piezoelectric constant. This precise parameter control prevents the degradation of piezoelectric performance while maintaining high mechanical quality factor across the operating temperature range.
Solution Approach 2:
The patent introduces localized structural modifications through Mn doping and precise stoichiometric control, creating regions with enhanced piezoelectric properties that stabilize performance across temperature variations. This local quality enhancement ensures consistent high-temperature performance.
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 exhibits improved piezoelectric performance and mechanical reliability at low temperatures, enhancing the efficiency and durability of devices like liquid discharge heads, ultrasonic motors, and optical apparatuses while being environmentally friendly.
Implementation Method 1
piezoelectric material having a main component containing a perovskite-type metal oxide
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A piezoelectric material contains a main component containing a perovskite-type metal oxide having the formula (1); a first auxiliary component composed of Mn; and a second auxiliary component composed of Bi or Bi and Li, wherein the Mn content is 0.04 parts by weight or more and 0.400 parts by weight or less on a metal basis per 100 parts by weight of the metal oxide, the Bi content is 0.042 parts by weight or more and 0.850 parts by weight or less on a metal basis per 100 parts by weight of the metal oxide, and the Li content is 0.028 parts by weight or less (including 0 parts by weight) on a metal basis per 100 parts by weight of the metal oxide. (Ba1-xCax)a(Ti1-y-zSnyZrz)O3 (1) (wherein 0 ≤ x ≤ 0.080, 0.013 ≤ y ≤ 0.060, 0 ≤ z ≤ 0.040, and 0.986 ≤ a ≤ 1.020.)