Multilayer Ceramic Capacitor Electrode Hardness
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Solution Overview
Problem
Conventional multilayer ceramic capacitors with external electrodes containing metal and dielectric grains face a decrease in hardness and adhesion strength, particularly when the electrode thickness is reduced to 10 μm or less, leading to potential cracking and separation from the capacitor body.
Innovation Solution
Incorporating a metal oxide of the same metal element at the interface between metal and dielectric grains in the external electrodes, which increases bonding strength and reduces residual stress, thereby maintaining hardness and preventing separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If external electrode paste contains dielectric grains to increase adhesion strength, then adhesion strength is improved, but hardness drops due to cracking at metal-grain/dielectric-grain interfaces
Solution Approach 1:
A metal oxide layer is introduced as an intermediary substance at the interface between metal grains and dielectric grains in the external electrode paste. This metal oxide layer prevents direct contact between metal and dielectric grains, eliminating the cracking issue while maintaining adhesion strength. The metal oxide acts as a buffer that resolves the harmful interaction between the two grain types.
Solution Approach 2:
The external electrode paste is formulated as a composite material containing metal grains, dielectric grains, and metal oxide. This composite structure leverages the advantages of each component: metal grains provide conductivity, dielectric grains enhance adhesion to the capacitor body, and metal oxide prevents interface cracking, thereby maintaining both adhesion strength and hardness simultaneously.
2Length of moving object
If external electrode thickness is reduced to meet miniaturization demands, then device size is reduced, but adhesion strength and hardness decrease leading to separation
Solution Approach 1:
The external electrode uses a composite paste formulation with metal grains, dielectric grains, and metal oxide that maintains high adhesion strength and hardness even at reduced thicknesses of 10 μm or less. The synergistic combination of components compensates for the reduced thickness, preventing separation while enabling miniaturization.
Solution Approach 2:
The metal oxide layer serves as a protective intermediary that prevents cracking and maintains structural integrity at thin electrode thicknesses. This intermediary layer ensures that even when the electrode is reduced to 10 μm or less, the adhesion strength is sufficient to prevent separation from the capacitor body.
3Length of moving object
If external electrode thickness is reduced, then device size is reduced, but hardness drops making electrodes more susceptible to damage
Solution Approach 1:
The composite external electrode paste containing metal grains, dielectric grains, and metal oxide maintains high hardness even when thickness is reduced to 10 μm or less. The combination of hard metal oxide and interlocking grain structure provides resistance to scratching and damage despite the reduced thickness.
Solution Approach 2:
The metal oxide layer acts as a protective intermediary that prevents the formation of cracks at metal-grain/dielectric-grain interfaces, thereby maintaining hardness even at reduced electrode thicknesses. This intermediary prevents the degradation that would normally occur in thinner electrodes.
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 presence of metal oxide at the interface between metal and dielectric grains enhances the bonding strength, maintains the hardness of the external electrodes, and prevents separation from the capacitor body, even at reduced thicknesses, while also reducing costs by using base metal grains.
Implementation Method 1
a metal oxide of the same metal element constituting the metal grain is present at the interface between the metal grain and the dielectric grain of the external electrodes
Data Source
AI summary
In an embodiment, a multilayer ceramic capacitor 10 has a first external electrode 12 and a second external electrode 13 that each contain metal grains MP and dielectric grains DP, where an oxide of the same metal element constituting the metal grain MP, or MO, is present at the interface between the metal grain MP and the dielectric grain DP. The multilayer ceramic capacitor can prevent the hardness of its external electrodes from dropping, even when the external electrodes contain metal grains and dielectric grains.