Piezoelectric Ceramic Composition Low-Temperature Firing
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Solution Overview
Problem
Conventional piezoelectric/electrostrictive ceramic compositions face challenges in achieving high density and excellent crystallinity at lower firing temperatures while maintaining satisfactory piezoelectric characteristics, due to the instability of the perovskite structure and volatilization of Bi at high temperatures, leading to reduced insulating performance.
Innovation Solution
A piezoelectric/electrostrictive ceramic composition is developed using a combination of ABO3 compounds with Bi at the A site and specific B1 and B2 elements, where the B1 element has an ionic valence of two or less and the B2 element has an ionic valence of four or more, dissolved in a Pb-based ABO3 compound, allowing for low-temperature firing and improved electric-field-induced strain properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a sintering agent is used to reduce the firing temperature, then the firing temperature is reduced, but the original piezoelectric/electrostrictive properties may be reduced
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating specific elements (Nb, Ta, Mo, W) with high ionic valence at the B-site of the perovskite structure. This compositional parameter change enables the ceramic to achieve densification and maintain piezoelectric properties at lower firing temperatures without requiring traditional sintering agents that would degrade performance.
Solution Approach 2:
The patent creates a composite ceramic system by combining multiple elements (Bi, Pb, Nb, Ta, Mo, W) in a perovskite structure. This composite approach allows the material to simultaneously achieve low-temperature sinterability (from Bi and Pb) and excellent piezoelectric properties (from the high-valence B-site elements), resolving the contradiction between temperature reduction and property maintenance.
2Strength
If Bi is used at the A site to promote deformation, then deformation is enhanced, but insulating performance is reduced due to volatilization of Bi at high temperatures
Solution Approach 1:
The patent changes the ionic valence parameter at the B-site by introducing elements with +4 or +5 valence (Nb, Ta, Mo, W). This parameter change compensates for the volatility issue of Bi by creating a more stable perovskite structure that maintains both deformation capability and insulating performance even at reduced firing temperatures where Bi volatilization is minimized.
3Strength
If the perovskite structure is synthesized with Bi at the A site, then deformation is promoted, but the structure is hard to be synthesized or density is low
Solution Approach 1:
The patent changes the B-site composition parameters by incorporating high-valence elements (Nb, Ta, Mo, W) that stabilize the perovskite structure. This parameter change enables successful synthesis of the perovskite phase with Bi at the A-site, achieving both the desired deformation properties and high density/crystallinity that were previously difficult to obtain.
Solution Approach 2:
The high-valence B-site elements (Nb, Ta, Mo, W) act as intermediaries that stabilize the perovskite structure formed by Bi at the A-site. These intermediary elements facilitate the formation of a stable, high-density crystalline structure that maintains both the deformation capability from Bi and the manufacturing precision required for practical applications.
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 composition achieves high density, excellent crystallinity, and superior piezoelectric/electrostrictive properties even at lower firing temperatures, with enhanced electric-field-induced strain and insulating performance.
Implementation Method 1
piezoelectric/electrostrictive ceramic compositions that are densified at a firing temperature of less than 1000° C.
Implementation Method 2
exhibits high density and excellent crystallinity
Implementation Method 3
piezoelectric/electrostrictive properties
Implementation Method 4
piezoelectric/electrostrictive properties
Data Source
AI summary
A piezoelectric/electrostrictive ceramic composition is provided which exhibits high density and excellent crystallinity even in the case of firing under lower temperature conditions than in conventional cases, and which also exhibits excellent piezoelectric/electrostrictive properties. An ABO3 compound (first main component) with Bi at the A site and with B1 and B2 elements at the B site (B1 consists of at least one kind of element having an ionic valence of two or less and selected from the group consisting of Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, and rare-earth elements; and B2 consists of at least one kind of element having an ionic valence of four or more and selected from the group consisting of V, Nb, Ta, Sb, Mo, and W) is dissolved in the form of a solid solution into another ABO3 compound (second main component) with at least Pb at the A site.