Perovskite Oxide Electrode for Ceramic Substrates
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Solution Overview
Problem
Conventional electrode materials for ceramic products and piezoelectric elements face challenges such as high production costs, limited substrate compatibility, and the need for expensive noble metals, as well as issues with conductivity and adhesion, particularly when fired under specific temperature conditions.
Innovation Solution
A conductive oxide sintered compact with a perovskite oxide crystal structure, represented by the composition formula REaCobCucNidOx, where RE is a rare-earth element, offering adjustable firing temperatures between 1100°C to 1500°C and high room-temperature conductivity, suitable for use as electrodes in ceramic products and piezoelectric elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal electrodes (Ni, Cu, W) are used with ceramic substrates, then electrical conductivity is achieved, but atmosphere control is required during firing which increases production cost and complicates the process
Solution Approach 1:
The invention changes the material parameter from conventional metals (Ni, Cu, W) to oxide materials with specific compositional parameters (La-Co-Ni-O system with controlled ratios). This parameter change allows the electrode material to be fired in air atmosphere without requiring reducing atmosphere control, thereby simplifying the manufacturing process while maintaining electrical conductivity.
Solution Approach 2:
The invention replaces expensive noble metals (Pd, Ir, Pt) with cheaper oxide materials that can be fired in air. The use of La-Co-Ni-O composite oxide provides cost-effective electrical conduction without the need for expensive materials, achieving both cost reduction and manufacturing simplification.
2Temperature
If Ag electrode is used, then low firing temperature (962°C) is achieved, but the material of ceramic substrate becomes limited and substrate properties may be impaired
Solution Approach 1:
The invention changes the firing temperature parameter from low (Ag at 962°C) to moderate range (1000-1300°C) using La-Co-Ni-O oxides. This temperature parameter change expands substrate compatibility to include various ceramic materials like alumina, zirconia, and piezoelectric ceramics that can withstand higher temperatures without property impairment.
Solution Approach 2:
The La-Co-Ni-O oxide electrode material provides universal compatibility with multiple ceramic substrate types (alumina, zirconia, piezoelectric ceramics) across a wide temperature range. The material serves multiple functions: electrical conduction, adhesion to various substrates, and thermal stability, making it versatile for different applications.
3Reliability
If noble metals (Pd, Ir, Pt) are used for electrodes, then electrical conductivity and adhesion are improved, but production cost increases significantly
Solution Approach 1:
The invention replaces expensive noble metals (Pd, Ir, Pt) with cheap oxide materials (La-Co-Ni-O composite). The oxide electrode provides sufficient electrical conductivity and adhesion performance at a fraction of the cost of noble metals, achieving cost-effective electrode solutions for large-area applications.
Solution Approach 2:
The invention uses a composite oxide material (La-Co-Ni-O) that combines multiple elements to achieve properties comparable to noble metals. The composite structure provides synergistic effects: La provides perovskite structure stability, Co and Ni provide electrical conductivity, and the composite formulation achieves both low cost and high performance.
4Quantity of substance
If conventional oxides are used as electrode materials, then cost is reduced, but conductivity is much lower and B-value is larger making them unsuitable as metal electrode substitutes
Solution Approach 1:
The invention creates a composite oxide (La-Co-Ni-O) that combines the advantages of individual oxides. The composite structure provides high electrical conductivity comparable to metals while maintaining the cost advantage of oxide materials. The perovskite-based composite achieves both low cost and high conductivity, overcoming the limitations of conventional single oxides.
Solution Approach 2:
The invention optimizes compositional parameters (ratios of La, Co, Ni, and O) to achieve maximum electrical conductivity. By controlling the stoichiometry and phases in the La-Co-Ni-O system, the material achieves conductivity levels suitable for electrode applications while maintaining oxide material cost benefits.
5Quantity of substance
If La(Co,Ni)O3 oxide is used as electrode material, then cost is reduced compared to noble metals, but the oxide develops cracks which causes increase in electrical resistance
Solution Approach 1:
The invention improves upon La(Co,Ni)O3 by creating a composite oxide system with optimized phase composition. The composite La-Co-Ni-O material maintains the cost advantage while improving structural integrity through controlled phase distribution and grain boundary characteristics that prevent crack formation and propagation.
Solution Approach 2:
The invention optimizes compositional parameters beyond simple La(Co,Ni)O3 stoichiometry. By adjusting the ratios of La, Co, Ni and oxygen content, and controlling sintering parameters, the material achieves improved structural stability and crack resistance while maintaining electrical conductivity and cost effectiveness.
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 cost-effective, conductive oxide material that can be fired under an air atmosphere at lower temperatures, enhancing adhesion and reducing the risk of warpage or cracking, while maintaining high conductivity and sinterability, making it suitable for various electronic components.
Implementation Method 1
an oxide sintered compact containing a crystal phase that has a perovskite oxide crystal structure... having a room-temperature conductivity of 100 S/cm or more and a firing temperature of 1100° C. to 1500° C.
Implementation Method 2
electrically conductive oxide sintered compact... having a room-temperature conductivity of 100 S/cm or more... small B constant (temperature coefficient)
Data Source
AI summary
An electrically conductive oxide sintered compact according to one embodiment of the present invention includes a crystal phase that has a perovskite oxide crystal structure represented by the composition formula: REaCobCucNidOx where RE is a rare-earth element; a+b+c+d=1; and 1.25≤x≤1.75, wherein the values of a, b, c and d respectively satisfy the following conditions: 0.474≤a≤0.512; 0.050≤b≤0.350; 0≤c≤0.250; and 0.050≤d≤0.350.