Perovskite Composite Oxide Grain Refinement via Calcium Substitution
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Solution Overview
Problem
Current methods for producing perovskite-type composite oxides, such as barium titanate-based ceramics, face challenges in achieving fine grain sizes and high crystallinity necessary for reducing dielectric layer thickness in laminated ceramic capacitors to submicrometer levels, while maintaining reliability and efficiency.
Innovation Solution
A method involving a reaction step of titanium oxide, calcium compound, and barium hydroxide in a slurry solution, using calcium acetate or calcium nitrate as the calcium source, followed by heat treatment, to produce a perovskite-type composite oxide with a calcium substitution range of 0<x≦0.20, enhancing solid solubility and crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce perovskite-type composite oxide, then production cost and time are reduced, but grain size and crystallinity are insufficient for submicrometer dielectric layers
Solution Approach 1:
The invention changes the chemical composition parameters by introducing calcium substitution at the barium site with a controlled substitution ratio (x) ranging from 0.01 to 0.20. This parameter change in the chemical formula (Ba1-xCax)mTiO3 optimizes both grain refinement and crystallinity enhancement, achieving submicrometer dielectric layers while maintaining production efficiency through a straightforward solid-state reaction process
Solution Approach 2:
The invention creates a composite perovskite-type material by combining barium titanate with calcium substitution. The resulting (Ba1-xCax)mTiO3 composite structure integrates the advantages of both materials, achieving fine grain size and high crystallinity necessary for submicrometer dielectric layers while maintaining piezoelectric and dielectric properties
2Volume of moving object
If dielectric layer thickness is reduced to submicrometer level, then capacitor size is reduced, but grain size control becomes more difficult
Solution Approach 1:
The invention introduces calcium substitution parameter (x) as a control variable to regulate grain growth during sintering. By optimizing the substitution ratio within the range of 0.01 to 0.20, the material achieves fine grain size that matches the reduced dielectric layer thickness, enabling precise grain size control in submicrometer-scale capacitors
Solution Approach 2:
The invention performs preliminary compositional modification by incorporating calcium substitution into the perovskite structure before the final sintering process. This preliminary action of compositional tuning prepares the material to achieve desired fine grain size and high crystallinity during subsequent processing, facilitating submicrometer dielectric layer fabrication
3Ease of manufacture
If calcium carbonate is used as calcium source, then production cost is reduced, but reaction completeness and crystallinity are compromised
Solution Approach 1:
The invention optimizes the reaction parameters including sintering temperature, holding time, and atmosphere conditions to ensure complete reaction when using calcium carbonate as the calcium source. By adjusting these parameters within specific ranges, the method achieves both cost-effectiveness of using calcium carbonate and high reaction completeness with excellent crystallinity in the final perovskite structure
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
This method efficiently produces fine, highly crystalline perovskite-type composite oxides, improving the reliability and performance of laminated ceramic capacitors by increasing the c/a axial ratio and extending the mean time to failure, enabling smaller, high-performance capacitors with reduced dielectric layer thickness.
Implementation Method 1
a reaction step of reacting at least titanium oxide, a calcium compound, and barium hydroxide in a slurry solution, thereby producing a perovskite-type composite oxide
Implementation Method 2
the method further includes a step of applying a heat treatment to the perovskite-type composite oxide produced in the reaction step
Implementation Method 3
efficiently produces fine, highly crystalline perovskite-type composite oxides, improving the reliability and performance of laminated ceramic capacitors by increasing the c/a axial ratio
Data Source
AI summary
A method is provided which includes a reaction step of reacting at least titanium oxide, a calcium compound, and barium hydroxide in a slurry solution so as to produce a perovskite-type composite oxide. The perovskite-type composite oxide is represented by (Ba1-xCax)mTiO3, and x is within a range of 0<x≦̸0.125. In addition, the method provides a perovskite-type composite oxide in which a water-soluble calcium compound is used as the calcium compound, and when the perovskite-type composite oxide is represented by (Ba1-xCax)mTiO3, x is within a range of 0<x≦̸0.20.