Multilayer Ceramic Capacitor Electrode Composition for High-Field Reliability
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Solution Overview
Problem
Multilayer ceramic capacitors with Ni as a main component in the inner electrode face reliability issues under high electric field intensity, which is exacerbated by thinner dielectric layers required for miniaturization and higher capacitance.
Innovation Solution
The inner electrodes are composed of alternating first and second metal compositions, where the first electrodes contain Ni or Cu as the main component and the second electrodes contain noble metals like Au, Pt, Ir, Pd, Os, Ag, Rh, or Ru with higher standard electrode potentials, to induce a redox reaction that prevents negative electrode segregation of oxygen ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dielectric layers are made thinner to achieve miniaturization and higher capacitance, then the capacitance and size requirements are met, but the electric field intensity increases and reliability during voltage application deteriorates
Solution Approach 1:
The patent applies different metal compositions to different inner electrodes based on their functional roles. First inner electrodes (positive electrodes) use Ni or Cu as main components, while second inner electrodes (negative electrodes) use metals with higher standard electrode potentials (Au, Pt, Ir, Pd, Os, Ag, Rh, Ru). This local differentiation addresses the reliability issue by preventing oxygen ion segregation specifically at the negative electrodes where it occurs most severely under high electric field conditions.
Solution Approach 2:
The patent employs composite material strategies by combining different metal elements in specific compositions. The first metal composition includes Ni or Cu as main components potentially combined with other elements, while the second metal composition uses noble metals or metals with high standard electrode potentials. These composite compositions provide synergistic effects that enhance both capacitance performance and reliability under high electric field intensity.
2Ease of manufacture
If Ni is used as the main component of inner electrodes, then manufacturing cost is reduced, but reliability during voltage application becomes insufficient
Solution Approach 1:
The patent strategically places Ni or Cu as main components only in the first inner electrodes (positive electrodes) where cost sensitivity is high, while using more expensive metals with higher standard electrode potentials in the second inner electrodes (negative electrodes) where reliability is critical. This local quality differentiation maintains cost effectiveness overall while ensuring reliability at the critical negative electrode interfaces.
Solution Approach 2:
The patent converts the potential harm of using inexpensive Ni/Cu metals into a benefit by carefully selecting which electrodes receive these materials. The first inner electrodes use cost-effective Ni or Cu, while the second inner electrodes use metals with higher standard electrode potentials to prevent oxygen ion segregation. This approach transforms a cost-saving measure into a reliability-enhancing strategy by leveraging the electrochemical properties of different metals in their optimal positions.
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 enhances the reliability of multilayer ceramic capacitors by reducing insulation degradation during voltage application, ensuring excellent performance even under high electric field conditions.
Implementation Method 1
the second inner electrodes have a second metal composition including at least one metal element selected from Au, Pt, Ir, Pd, Os, Ag, Rh, and Ru, which have standard electrode potentials higher than that of Cu, as a main component
Data Source
AI summary
In a multilayer ceramic capacitor including first and second inner electrodes alternately arranged with respect to a stacking direction of a multilayer body, a polarity based on a direction of voltage applied between a first outer electrode and a second outer electrode is determined such that the first inner electrodes function as positive electrodes and the second inner electrodes function as negative electrodes. The first inner electrodes have a first metal composition including Ni or Cu as a main component, and the second inner electrodes have a second metal composition including at least one metal element selected from Au, Pt, Ir, Pd, Os, Ag, Rh, and Ru, which have standard electrode potentials higher than that of Cu, as a main component.