Multilayer Ceramic Capacitor Inner Electrode Defect Control
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Solution Overview
Problem
Multilayer ceramic capacitors face defects in inner electrodes, leading to reduced electrostatic capacity due to discontinuous regions, which are exacerbated by thinning the electroconductive paste during firing.
Innovation Solution
The use of a dielectric ceramic composition with a perovskite compound containing Ba and Ti, and inner electrodes made from an electroconductive paste with Ni and Mg, where the Mg content is adjusted to ensure at least 20% of defects contain Mg, inhibiting Ni grain growth and reducing defects in the inner electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the printing thickness of the electroconductive paste is reduced to thin the inner electrodes, then the capacitor size is reduced and capacity is increased, but defects and discontinuous regions in the inner electrodes become more likely, resulting in reduced inner electrode coverage and electrostatic capacity
Solution Approach 1:
The patent changes the chemical composition parameters of the electroconductive paste by adding Mg as an accessory component alongside Ni. This compositional parameter change modifies the firing behavior and grain growth characteristics of the inner electrode material, enabling thinner electrodes (reducing capacitor size) while maintaining sufficient continuity and coverage (preserving reliability).
Solution Approach 2:
The patent creates a composite electroconductive paste material consisting of Ni as the primary electroconductive component and Mg as an accessory component. This composite material exhibits synergistic effects during firing, where Mg influences Ni grain growth and sintering behavior, allowing the inner electrodes to maintain adequate coverage even at reduced thicknesses, thus resolving the contradiction between miniaturization and reliability.
2Quantity of substance
If the inner electrode thickness is reduced to increase capacitance density, then the electrostatic capacity per volume is improved, but the inner electrodes become more prone to discontinuities and defects, reducing overall electrostatic capacity
Solution Approach 1:
The patent modifies the material composition parameters of the electroconductive paste by incorporating Mg alongside Ni. This parameter change alters the sintering characteristics and grain growth kinetics during firing, enabling the production of thinner, more continuous inner electrodes with fewer defects, thereby improving both capacitance density and manufacturing precision simultaneously.
Solution Approach 2:
Mg acts as an intermediary component in the electroconductive paste that mediates the sintering process of Ni particles. During firing, Mg influences the diffusion and bonding behavior of Ni grains, promoting the formation of continuous, defect-free thin electrodes. This intermediary effect allows achieving high electrode continuity even at reduced thicknesses, resolving the contradiction between capacitance density 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 approach results in reduced loss of inner electrode coverage and improved electrostatic capacity by controlling the Mg content and using a Mg-Ni composite oxide to minimize defects in the inner electrodes, particularly when the inner electrode thickness is 0.5 μm or less.
Implementation Method 1
Mg as an accessory component... inhibiting Ni grain growth
Implementation Method 2
Mg-Ni composite oxide to minimize defects
Data Source
AI summary
A multilayer ceramic capacitor that includes dielectric layers made mainly of a perovskite compound containing Ba and Ti and optionally Zr and Hf, and inner electrodes having an average thickness of approximately 0.5 μm or less. The Mg content of the dielectric layers is approximately in the range of 0≦Mg≦0.4 (parts by mole) based on a total of 100 parts by mole of Ti, Zr, and Hf. The proportion of Mg-containing defects in the inner electrodes is approximately 20% or more.