Multilayer Ceramic Capacitor Hydrogen Trapping Electrode
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Solution Overview
Problem
The use of base metals like Ni for internal electrodes in multilayer ceramic capacitors leads to hydrogen generation during the plating process, causing deterioration of insulation resistance due to hydrogen diffusion into dielectric layers.
Innovation Solution
Incorporating elements that form covalent hydrides or hydrides with hydrogen, such as Sn, Bi, Al, Ag, Zn, Au, In, Ga, Ge, or Si, into the external or internal electrodes to act as hydrogen-holding agents, preventing hydrogen diffusion into the dielectric layers through the formation of hydrogen-holding films or by blending these elements into the electrode materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If base metal (Ni) is used for internal electrode to reduce material costs, then manufacturing cost is reduced, but hydrogen is generated during plating step causing deterioration of insulation resistance
Solution Approach 1:
A hydrogen-holding layer is introduced as an intermediary between the Ni internal electrode and the dielectric layer. This layer contains elements (Ti, V, Zr, Nb, Ta, or Hf) that have high hydrogen affinity and form stable hydrides, acting as a mediator to trap hydrogen before it can reach and damage the dielectric layer, thus resolving the contradiction between using low-cost Ni and maintaining insulation resistance
Solution Approach 2:
The internal electrode structure is transformed into a composite material system consisting of Ni internal electrode + hydrogen-holding layer. The hydrogen-holding layer is formed by stacking a metal oxide layer containing Ti, V, Zr, Nb, Ta, or Hf and then irradiating it with ion beams to create a nanocrystalline structure with high hydrogen trapping capacity, preventing hydrogen diffusion while maintaining the cost advantage of Ni
2Reliability
If Ni plating is applied to external electrode to prevent solder dissolution, then soldering performance is improved, but hydrogen ions are generated and occluded into internal electrode causing dielectric layer deterioration
Solution Approach 1:
The hydrogen ions generated as a harmful byproduct of the necessary Ni plating process are converted into a beneficial trapped state within the hydrogen-holding layer. The layer's high hydrogen affinity and stable hydride formation capability transform the harmful hydrogen into a benign trapped state, eliminating its damaging effects while preserving the soldering performance benefits of Ni plating
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 incorporation of these elements effectively suppresses hydrogen diffusion, thereby preventing the deterioration of insulation resistance in multilayer ceramic capacitors, even under conditions of elevated temperature and voltage.
Implementation Method 1
at least one kind of an element forming a covalent hydride with hydrogen (however, except for an element generating hydride having a boiling point of less than 125° C.) and an element forming a hydride in a boundary region with hydrogen is contained between an outermost plating layer among the plating layers and the dielectric layers
Implementation Method 2
the element forming a covalent hydride with hydrogen... is an element which belongs to a boron group (except for In and Tl), a carbon group, a nitrogen group, an oxygen group, and halogen in a long-form periodic table
Implementation Method 3
a metal oxide layer including at least one element selected from the group consisting of Ti, V, Zr, Nb, Ta, and Hf; and an ion beam irradiation section in which the metal oxide layer is irradiated with an ion beam
Data Source
AI summary
A multilayer ceramic capacitor that contains at least one kind of a first element that forms a covalent hydride with hydrogen (except for an element generating a hydride having a boiling point of less than 125° C.) and a second element that forms a hydride in a boundary region with hydrogen between an outermost plating layer constituting an external electrode and a dielectric layer constituting a ceramic element body.