Laminated Ceramic Component Electrode Erosion Resistance
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Solution Overview
Problem
Laminated ceramic capacitors face mechanical strength issues due to crack generation caused by plating solutions eroding the ceramic body at the end edges of external electrodes, leading to decreased reliability and performance.
Innovation Solution
Incorporating a crystalline substance containing Ba, Ti, and Si at the grain boundaries of the ceramic body, formed through heat treatment of a conductive paste with a glass component, which provides dissolving resistance against plating solutions and enhances mechanical strength by preventing erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wet plating is applied to external electrodes to improve solderability, then mountability is improved, but mechanical strength decreases due to crack generation
Solution Approach 1:
The patent applies different treatments to different regions: the external electrode surface receives plating for solderability, while the end edges (which are not plated) receive a protective glass component coating. This local differentiation allows solderability improvement without compromising mechanical strength at vulnerable unplated regions.
Solution Approach 2:
The glass component is applied in advance to the end edges of external electrodes before plating. This preliminary protective layer prevents plating solution from eroding the ceramic body at these vulnerable locations, thereby preventing crack generation that would otherwise occur during subsequent plating and mounting processes.
2Ease of operation
If plating solutions are used for wet plating to achieve good solderability, then external electrodes become more mountable, but ceramic body deteriorates at end edges
Solution Approach 1:
The glass component acts as an intermediary protective layer between the plating solution and the ceramic body at the end edges. This intermediate layer prevents direct contact between the harmful plating solution and the ceramic, thereby preventing erosion and deterioration while still allowing the plating process to proceed on the electrode surfaces.
Solution Approach 2:
The patent converts the potentially harmful exposure of end edges to plating solutions into a benefit by deliberately applying a glass component coating. This transforms the vulnerable unplated regions into protected zones that prevent ceramic body deterioration, turning what would be a weakness into a strength.
3Strength
If glass component penetrates into grain boundaries during heat treatment to form external electrode, then electrode adhesion is improved, but ceramic body becomes more susceptible to erosion
Solution Approach 1:
The patent creates a dual-layer glass component structure: an inner layer that penetrates grain boundaries for adhesion, and an outer layer applied to end edges for erosion protection. This local differentiation allows the glass component to simultaneously provide both adhesion and protection functions in different regions.
Solution Approach 2:
The external electrode structure becomes composite: the base conductive paste provides electrical conductivity, the penetrating glass component provides adhesion by bonding to ceramic grains, and the additional glass component coating on end edges provides erosion resistance. This composite structure achieves multiple functions simultaneously.
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 crystalline substance effectively suppresses crack generation at the end edges of external electrodes, thereby enhancing the mechanical strength and weather resistance of laminated ceramic electronic components, even when subjected to plating processes.
Implementation Method 1
In the heat treatment step, the glass component in the conductive paste penetrates into grain boundaries 17 between ceramic grains 16 of the ceramic body 2 to form a reaction phase 18
Implementation Method 2
External electrodes 3 and 4 are formed by applying a conductive paste, and carrying out heat treatment (baking)
Data Source
AI summary
An external electrode included in a laminated ceramic electronic component is formed on a ceramic body by baking a conductive paste including a glass component. The ceramic body with the conductive paste applied thereto is subjected to heat treatment under the conditions where the top temperature is 800° C. or higher, and the electromotive force at the top temperature is 600 to 900 mV. In this heat treatment, the glass component in the conductive paste penetrates into grain boundaries between ceramic grains of the ceramic body, and a crystalline substance containing elements constituting the glass component is generated which has dissolving resistance against plating solutions.