Ceramic Capacitor Electrode Paste for Ultra-Low AC Capacity Stability
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Solution Overview
Problem
Multilayer ceramic capacitors experience reduced electrical capacity and degraded performance at low AC voltages, particularly below 50 mVrms, due to the reaction of co-materials with dielectric materials during sintering, which affects the AC voltage characteristic and reliability.
Innovation Solution
Incorporating amorphous silica as a co-material in the metal conductive paste for internal electrode layers that does not react with the main component ceramic at firing temperatures, acting as a steric hindrance to delay sintering and prevent grain growth, thereby improving AC voltage characteristics without compromising electrode continuity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional metal conductive paste containing reactive co-materials is used, then electrode continuity is maintained, but capacity reduction occurs at ultra-low AC voltages due to reactions during sintering
Solution Approach 1:
The patent changes the chemical composition parameter of the co-material from reactive materials (such as BaTiO3, CaZrO3) to inert amorphous silica. This parameter change eliminates the harmful chemical reactions between co-material and dielectric material during sintering, thereby preventing capacity reduction at ultra-low AC voltages while maintaining electrode continuity.
Solution Approach 2:
The patent uses amorphous silica as a temporary co-material that serves its function during sintering (providing steric hindrance and delaying sintering) and then becomes an inert component in the final product. The amorphous silica effectively acts as a short-living functional material that achieves the desired effect and then remains as a stable, non-reactive component.
2Productivity
If sintering is accelerated to improve productivity, then manufacturing efficiency increases, but co-material reaction with dielectric material worsens, degrading AC voltage characteristic
Solution Approach 1:
The patent changes the chemical reactivity parameter of the co-material to be inert (amorphous silica), which allows the sintering process to be accelerated without causing harmful reactions. The inert nature of amorphous silica eliminates the trade-off between sintering speed and AC voltage characteristic, enabling both high productivity and high reliability.
3Volume of moving object
If dielectric layer thickness is reduced to achieve smaller device size, then miniaturization is achieved, but AC voltage characteristic degrades due to enhanced reaction effects
Solution Approach 1:
The patent changes the co-material to amorphous silica, which eliminates the chemical reaction component that degrades AC voltage characteristic. This allows dielectric layers to be made thinner for miniaturization without the harmful reaction effects that would otherwise be amplified in thinner structures, thus achieving both small size and high reliability.
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 approach effectively suppresses capacity reduction at ultra-low AC voltages, enhancing the AC voltage characteristic while maintaining high electrode continuity and reliability, without degrading other characteristics like insulation.
Implementation Method 1
Incorporating amorphous silica as a co-material in the metal conductive paste for internal electrode layers that does not react with the main component ceramic at firing temperatures, acting as a steric hindrance to delay sintering and prevent grain growth
Implementation Method 2
firing the multilayer structure
Data Source
AI summary
A ceramic electronic device includes a plurality of dielectric layers of which a main component is a ceramic having a perovskite structure, and a plurality of internal electrode layers, each of which is stacked through each of the plurality of dielectric layers and includes a co-material which is inactive against the main component of the plurality of dielectric layers.