Multilayer Ceramic Capacitor Pd-Plated Recesses Adhesion
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Solution Overview
Problem
Conventional multilayer ceramic capacitors experience reduced fixing force between external electrodes and conductive adhesive, especially after thermal stress, due to smooth surface finishes which compromise adhesion.
Innovation Solution
The external electrodes of the multilayer ceramic capacitors feature a Pd-plated layer with a rough surface texture, including a combination of small and large recesses, which increases the contact area and anchor effect with the conductive adhesive, enhancing the fixing strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the surface of the Pd-plated layer is made smooth, then the manufacturing precision is improved, but the fixing strength between external electrodes and conductive adhesive deteriorates
Solution Approach 1:
The patent applies the porous materials principle by intentionally creating a rough surface with recesses on the Pd-plated layer instead of using a smooth surface. The recesses form a porous-like structure that increases the contact area and mechanical interlocking with the conductive adhesive, thereby improving fixing strength while maintaining manufacturing feasibility through controlled plating processes.
Solution Approach 2:
The patent applies the curvature principle by creating rounded recesses on the surface of the Pd-plated layer. These curved surface features increase the surface area and provide better mechanical interlocking with the conductive adhesive compared to a flat smooth surface, resolving the contradiction between surface finish quality and fixing strength.
2Strength
If the amount of Pd used is increased, then the fixing strength is improved, but the cost increases
Solution Approach 1:
The patent uses the porous materials principle to create a rough surface structure with recesses on the Pd-plated layer. This increases the effective contact area and mechanical interlocking with the conductive adhesive, allowing for reduced Pd thickness while maintaining or improving fixing strength, thus reducing the total amount of expensive Pd material required.
Solution Approach 2:
The patent applies parameter changes by modifying the surface morphology parameters of the Pd-plated layer, specifically creating recesses with controlled depth and distribution. This changes the surface area and adhesion characteristics, enabling reduced Pd quantity while maintaining fixing strength through improved interfacial contact and mechanical interlocking.
3Strength
If the surface of the external electrode is made rough, then the fixing strength is improved, but the manufacturing precision deteriorates
Solution Approach 1:
The patent applies the porous materials principle by creating a controlled rough surface with recesses on the external electrode. This roughness is not random but systematically structured to improve fixing strength while maintaining manufacturing precision through controlled plating parameters and standardized recess dimensions.
Solution Approach 2:
The patent applies the local quality principle by creating recesses only in specific locations on the Pd-plated layer surface, rather than uniformly roughening the entire surface. This localized surface modification improves fixing strength at the adhesive interface while maintaining overall surface uniformity and manufacturing precision.
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 configuration significantly improves the fixing strength between the external electrodes and the conductive adhesive, while reducing the amount of expensive Pd used, thus achieving both high adhesion and cost-effectiveness.
Implementation Method 1
a plurality of recesses are provided on a surface of the Pd-plated layer... increases the contact area and anchor effect with the conductive adhesive, enhancing the fixing strength
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including stacked dielectric layers and stacked internal electrode layers, and external electrodes respectively connected to the internal electrode layers. The external electrodes each include a lower plated layer and a Pd-plated layer on the lower plated layer. Recesses are provided on a surface of the Pd-plated layer and include first recesses each having a circle equivalent diameter of an opening of about 0.5 μm or more and about 4 μm or less and second recesses each having a circle equivalent diameter of an opening of about 10 μm or more and about 22 μm or less. The first recesses are greater in number than the second recesses. The second recesses and the first recesses are in a mixed state.