CaTiO3 Dielectric Ceramic with Tin for Ni Electrode Compatibility
Solution Overview
Problem
Dielectric ceramics used in laminated ceramic capacitors face challenges in maintaining high insulation properties and stable electrical characteristics when calcined in a reducing atmosphere, requiring accessory components like oxides of V, Nb, W, Ta, and Mo, which are sensitive to compositional variations.
Innovation Solution
A dielectric ceramic composition based on (Ca1-xBax)TiO3 or (Ca1-x-yBaxSny)TiO3 with Sn as a main component, where 1 part by mol of Sn is added to 100 parts by mol, providing high insulation properties and resistance to reduction, allowing the use of Ni for internal electrodes and stabilizing electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If accessory components like oxides of V, Nb, W, Ta, and Mo are added to ensure insulation properties and reliability, then insulation properties are improved, but compositional variation sensitivity increases and manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates the accessory components (oxides of V, Nb, W, Ta, Mo) from the ceramic composition, retaining only the main component (Ca1-xBax)TiO3. This removal of unnecessary components simplifies the composition while maintaining the required insulation properties through the optimized main component formulation.
Solution Approach 2:
The patent changes the compositional parameters by defining specific ranges for x (0 < x ≤ 0.3) and y (0 < y ≤ 0.1) in the (Ca1-x-yBaxSny)TiO3 formula. These parameter changes optimize the electrical characteristics and insulation properties while reducing sensitivity to compositional variations, eliminating the need for expensive accessory oxides.
2Ease of manufacture
If Ni is used for internal electrodes to reduce manufacturing cost, then manufacturing cost is reduced, but oxidation resistance deteriorates in calcination atmosphere
Solution Approach 1:
The patent introduces a reducing atmosphere during calcination as an intermediary condition that protects the Ni internal electrodes from oxidation. The reducing atmosphere acts as a mediator between the Ni electrodes and the oxidizing environment, enabling the use of low-cost Ni while maintaining electrode integrity through controlled atmospheric conditions.
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 dielectric ceramic composition ensures high insulation properties and stable electrical characteristics even in a reducing atmosphere, enabling the use of Ni for internal electrodes and reducing manufacturing costs while maintaining capacitance and resistivity.
Implementation Method 1
the dielectric ceramic material is required to have resistance to reduction. As a material which exhibits a certain level of insulation properties even after calcination under a reducing atmosphere
Implementation Method 2
The external electrodes are formed, for example, by providing a conductive paste containing conductive metal powder and glass frit onto the outer surfaces of the laminated body and baking the conductive paste
Data Source
AI summary
A dielectric ceramic with stable insulation properties even after calcination under a reducing atmosphere, as is preferred for a laminated ceramic capacitor, is a CaTiO3 composition containing Sn. It is preferable for the dielectric ceramic to contain, as its main component, (Ca1-xBaxSny)TiO3 (0≦x<0.2, 0.01≦y<0.2) with a solution of Sn at the B site.