MLCC Metal Oxide Coating for Moisture-Resistant Exposed Surfaces
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with moisture intrusion through voids in the dielectric layers, leading to potential short circuits due to exposed surfaces without external electrode coverage.
Innovation Solution
A metal oxide coating is applied to the exposed surfaces of the multilayer ceramic capacitor, which are not covered by external electrodes, to prevent moisture ingress and reduce the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the exposed surface is left uncovered by external electrodes, then the manufacturing process is simplified and cost is reduced, but moisture can penetrate through voids to internal electrodes causing short circuits
Solution Approach 1:
A glass-containing coating is applied as an intermediary layer on the exposed surface of the multilayer body. This coating acts as a mediator that seals voids and prevents moisture penetration while maintaining manufacturing simplicity. The glass component flows during firing to fill and seal the voids, creating a protective barrier without requiring complex manufacturing processes.
Solution Approach 2:
The surface properties of the exposed surface are changed by applying a coating with different material composition (glass-containing). This parameter change transforms the exposed surface from a moisture-permeable state to a moisture-resistant state. The coating changes the surface energy and physical structure to prevent moisture ingress while maintaining electrical insulation.
2Reliability
If a glass-containing coating is applied to the exposed surface, then moisture penetration is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The glass-containing coating is merged with the existing external electrode materials and dielectric layers. The coating composition includes glass that is compatible with the multilayer body materials, allowing the coating process to be integrated with the existing firing process. This merging reduces the need for separate, complex manufacturing steps while achieving effective moisture protection.
Solution Approach 2:
The glass-containing coating is applied as a relatively simple, cost-effective solution that provides sufficient protection without requiring complex, expensive manufacturing equipment or processes. The coating is applied in a straightforward manner and fired at temperatures compatible with existing production lines, avoiding the need for specialized complex processing equipment.
3Reliability
If the exposed surface is covered with metal oxide coating, then moisture resistance is improved, but the cost of materials and processing increases
Solution Approach 1:
The glass-containing coating is applied only to the exposed surface of the multilayer body, not to the entire capacitor structure. This localized application ensures that materials are used only where needed for moisture protection, avoiding unnecessary material costs on areas already protected by external electrodes. The coating thickness and composition are optimized for the specific requirements of the exposed surface.
Solution Approach 2:
The coating composition is changed from traditional metal oxide to a glass-containing formulation that provides equivalent or superior moisture protection at lower cost. The glass component offers effective void sealing and moisture barrier properties while being more cost-effective than precious metal oxides. The coating parameters are optimized to achieve the required protection with minimal material usage.
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 metal oxide coating effectively reduces moisture penetration, enhancing the moisture resistance reliability and minimizing the likelihood of short circuits by ensuring adequate coverage and non-coated regions.
Implementation Method 1
the exposed surface includes a metal oxide coating region coated with a metal oxide which is different from a component of the plurality of dielectric layers
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including an inner layer portion including dielectric layers and internal electrode layers that are laminated, two main surfaces opposed to each other in a lamination direction, two lateral surfaces opposed to each other in a width direction intersecting the lamination direction, two end surfaces opposed to each other in a length direction intersecting the lamination direction and the width direction, and two outer layer portions on both sides of the inner layer portion in the lamination direction, and external electrodes on the two end surfaces. The multilayer body includes an exposed surface that is not covered by the external electrodes. The exposed surface includes a metal oxide coating region coated with a metal oxide which is different from a component of the plurality of dielectric layers.