PNN-PZT Piezoelectric Element Humidity Insulation Stability
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Solution Overview
Problem
Conventional piezoelectric/electrostrictive actuators experience a significant decline in insulation resistance, especially in high-humidity environments, which affects their reliability and performance.
Innovation Solution
A PNN-PZT type piezoelectric/electrostrictive ceramic composition is developed, where a small part of Pb ions are substituted with Sr ions and a portion of Ni β/3 Nb 2/3 is replaced with Al γ/2 Nb 1/2, resulting in a composition formula (Pb 1-x Sr x ) α{ (Ti 1-y Zr y ) a (Ni β/3 Nb 2/3 ) b (Al γ/2 Nb 1/2 ) c}O 3, enhancing the stability of the crystal structure and maintaining desired displacement with reduced insulation resistance decline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional piezoelectric/electrostrictive ceramic compositions are used, then the actuator shows high insulation resistance value at early stage, but the insulation resistance value is remarkably declined when used under high-humidity environment
Solution Approach 1:
The patent modifies the chemical composition parameters of the PNN-PZT ceramic system by introducing Sr ion substitution at Pb sites and Al-Nb substitution at Ni-Nb sites. Specifically, x=0.005-0.03 for Sr content, y=0.46-0.54 for Ti-Zr ratio, a=0.58-0.91 for Ti-content parameter, b=0.07-0.36 for Ni-Nb parameter, and c=0.02-0.08 for Al-Nb parameter. These parameter changes optimize the crystal structure stability and reduce humidity-induced insulation resistance degradation while maintaining piezoelectric performance
Solution Approach 2:
The patent creates a composite ceramic system by combining multiple oxide components: Pb(Ni1/3Nb2/3)O3, PbTiO3, PbZrO3, SrTiO3, and AlNbO4 in specific proportions. This composite structure leverages the complementary properties of each component to achieve both high piezoelectric response and enhanced insulation resistance stability under humid conditions
2Length of moving object
If the thickness of the film is reduced to obtain large displacement, then the displacement increases in the same driving electric field, but the manufacturing precision and structural integrity become more challenging
Solution Approach 1:
The patent optimizes the composition parameters to achieve a balance between film thickness and displacement performance. By adjusting the Ti-Zr ratio (y=0.46-0.54) and the phase composition parameters (a, b, c), the material exhibits enhanced piezoelectric coefficients that allow thin films to achieve large displacements without compromising structural integrity or manufacturing feasibility
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 modified composition maintains a desired displacement comparable to conventional actuators while minimizing insulation resistance decline, even under high-humidity conditions, ensuring high reliability and performance.
Implementation Method 1
piezoelectric/electrostrictive element using a piezoelectric/electrostrictive body made of a PNN-PZT type piezoelectric/electrostrictive ceramic composition
Implementation Method 2
piezoelectric/electrostrictive element using a piezoelectric/electrostrictive body made of a PNN-PZT type piezoelectric/electrostrictive ceramic composition
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
There is provided a piezoelectric/electrostrictive element (1) comprising a piezoelectric/electrostrictive body (30) made of a piezoelectric/electrostrictive ceramic composition containing Pb (Ni1/3Nb2/3) O3-PbTiO3-PbZrO3 ternary solid solution system composition as the main components, and an electrode (10,10') disposed on the piezoelectric/electrostrictive body, wherein the ternary solid solution system composition is represented by the following composition formula: (Pb1-xSrx)α{(Ti1-yZry)a(Niβ/3Nb2/3)b(Alγ/2Nb1/2)c}O3 (where 0.005≤x≤0.03, 0.45≤y≤0.54, 0.58≤a≤0.91, 0.07≤b≤0.36, 0.02≤c≤0.08, 0.97≤α≤1.03, 0.97≤β≤1.03, 0.97≤γ≤1.03, and (a+b+c=1.000)).