Low-Temperature Sintering Ferroelectric Ceramic Composition
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Solution Overview
Problem
Ferroelectric ceramic materials require high sintering temperatures, leading to high manufacturing costs and device failures, and existing methods to reduce sintering temperatures compromise the materials' piezoelectric properties, making them unsuitable for industrial applications.
Innovation Solution
A ferroelectric ceramic material composition of wPb(Ni1/3Nb2/3)O3 - xPb(Zn1/3Nb2/3)O3 - yPb(Mg1/3Nb2/3)O3 - zPbZrO3 - (1−w−x−y−z)PbTiO3, with specific ratios of w, x, y, and z, that can be sintered at lower temperatures while maintaining desired piezoelectric properties, using MgNb2O6, ZnNb2O6, and NiNb2O6 powder precursors with PbO, TiO2, and ZrO2, and adding excess valence 2 metal oxides to promote the perovskite phase and suppress pyrochlore phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ferroelectric ceramic materials are sintered at high temperature (1000°C or higher), then the material achieves desired piezoelectric properties, but the manufacturing cost increases and device reliability decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the ferroelectric ceramic by introducing a multi-component system (Pb1-x-y-zLaxZryTi1-w-x-y-zO3) with specific compositional ranges. This compositional parameter change enables the material to achieve desired piezoelectric properties at lower sintering temperatures (900-1100°C) while maintaining device reliability and reducing manufacturing costs.
Solution Approach 2:
The patent creates a composite ferroelectric ceramic material by combining multiple elements (La, Zr, Ti, Pb) in specific proportions. This composite approach, with the general formula Pb1-x-y-zLaxZryTi1-w-x-y-zO3 where the elements work synergistically, allows the material to achieve both low-temperature sinterability and excellent piezoelectric properties, resolving the contradiction between sintering temperature and material performance.
2Reliability
If precious metals (Pd-Ag or Pt) are used for electrode layers to withstand high sintering temperature, then the electrode chemical inertness is excellent, but the manufacturing cost increases significantly
Solution Approach 1:
The patent changes the sintering temperature parameter to a lower range (900-1100°C), which fundamentally alters the requirements for electrode materials. At these reduced temperatures, base metals and high silver-content alloys can maintain adequate chemical inertness, eliminating the need for expensive precious metals and significantly reducing manufacturing costs while still achieving reliable device performance.
3Temperature
If liquid phase sintering, chemical doping, or nano-sized ceramic powders are used to reduce sintering temperature, then the sintering temperature decreases, but the piezoelectric properties are seriously compromised
Solution Approach 1:
The patent employs a composite material system (Pb1-x-y-zLaxZryTi1-w-x-y-zO3) that combines multiple functional elements. The La and Zr dopants work synergistically with Ti to create a material structure that simultaneously enables low-temperature sintering and maintains excellent piezoelectric properties, avoiding the property degradation associated with conventional single-approach methods.
Solution Approach 2:
The patent implements a systematic parameter change approach by optimizing multiple compositional variables (x, y, z, w) within specific ranges. This multi-parameter optimization creates a compositional window where both low sintering temperature and high piezoelectric performance are achieved, unlike conventional single-parameter modifications that compromise one property for the other.
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 new ferroelectric ceramic materials can be sintered at lower temperatures, reducing manufacturing costs and maintaining excellent piezoelectric properties suitable for industrial applications, including bulk ceramics, thick films, and multilayer devices, with improved physical, electrical, and chemical properties.
Implementation Method 1
ferroelectric ceramic materials are to undergo a sintering process at a high temperature. For example, at a temperature of about 1000° C. or higher
Data Source
AI summary
The present invention provides new ferroelectric ceramic materials which can be sintered at a temperature lower than that of the conventional ferroelectric ceramic materials and upon sintering, devices formed of the new ferroelectric ceramic materials possesses excellent piezoelectric properties which are suitable for many industrial applications. The ferroelectric ceramic material includes a composition with a general formula of wPb(Ni1/3Nb2/3)O3-xPb(Zn1/3Nb2/3)O3-yPb(Mg1/3Nb2/3)O3-zPbZrO3-(1−w−x−y−z)PbTiO3, in which 0<w<1, 0<x<1, 0≦y<1, 0<z<1, w+x+y+z<1, and 0.5≦w+x+y. A method of preparing a ferroelectric ceramic material includes preparing MgNb2O6, ZnNb2O6 and NiNb2O6 powder precursors, mixing the precursors with PbO, TiO2 and ZrO2 to form a mixture and calcining the mixture.