Dielectric Ceramic Composition for Base Metal Laminated Capacitors
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Solution Overview
Problem
Conventional laminated ceramic capacitors using dielectric ceramic compositions exhibit poor insulation resistance lifetime characteristics, large temperature variation rates of capacitance, and reduced insulation resistance when using base metals like nickel and copper, especially when the dielectric layer becomes thinner.
Innovation Solution
A dielectric ceramic composition containing specific amounts of Mg, Ba, Ln (Er, Dy, Ho), Mn, V, Si, and Al compounds, with a Ba/Ti molar ratio adjusted to 0.997-1.007, is used to form a laminated ceramic capacitor, where the ceramic powders are mixed, calcined, and sintered in a controlled atmosphere to prevent oxidation and enhance sintering properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If base metals like nickel and copper are used in inner electrodes and external electrodes to substitute expensive precious metals, then manufacturing cost is reduced, but insulation resistance deteriorates and reliability decreases
Solution Approach 1:
The patent modifies the chemical composition parameters of the dielectric ceramic by adding specific amounts of MgO (0.1-2.0 mol%), MnO (0.1-1.0 mol%), and SiO2 (0.5-3.0 mol%) to change the sintering behavior and microstructure, enabling the use of base metals without insulation resistance deterioration
Solution Approach 2:
The patent introduces MgO, MnO, and SiO2 as intermediary substances that mediate between the base metal electrodes and the dielectric layer, preventing direct harmful reactions while maintaining electrical insulation properties during sintering in reduced atmosphere
2Volume of moving object
If the dielectric layer is made thinner to reduce capacitor size, then miniaturization is achieved, but insulation resistance decreases and reliability becomes difficult to ensure
Solution Approach 1:
The patent changes the compositional parameters by adding MgO, MnO, and SiO2 to improve the intrinsic insulation properties of the dielectric material, allowing thinner layers to maintain adequate insulation resistance
Solution Approach 2:
The patent creates a composite dielectric system combining BaTiO3 with MgO, MnO, and SiO2 additives, where the composite structure provides both the dielectric functionality and enhanced insulation properties needed for thin-layer applications
3Stability of the object's composition
If sintering is performed in reduced atmosphere to prevent oxidation of base metal electrodes, then electrode integrity is maintained, but dielectric layer reduction deterioration occurs
Solution Approach 1:
The patent uses MnO and SiO2 as intermediary substances that form protective phases during sintering, acting as a buffer between the reduced atmosphere and the dielectric layer to prevent reduction deterioration while allowing base metal electrodes to maintain integrity
Solution Approach 2:
The patent optimizes the sintering temperature parameter (900-1100°C) and compositional parameters (MnO and SiO2 content) to create a window where reduced atmosphere sintering can proceed without causing dielectric layer reduction, balancing electrode protection with dielectric stability
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 approach results in laminated ceramic capacitors with improved dielectric constants, reduced dielectric loss tangents, stable insulation resistance, and minimal capacitance variation with temperature, maintaining high performance even when sintered with base metals.
Implementation Method 1
sintering is performed at a prescribed temperature. At this time, sintered body 15 is formed by performing sintering in a reduced atmosphere such as a nitrogen gas atmosphere to prevent oxidative deterioration of inner electrodes 13 and 14
Implementation Method 2
dielectric layer 12 is reduced and there is a problem that insulation resistance of the laminated ceramic capacitor becomes small
Data Source
AI summary
A dielectric ceramic composition containing at least 0.15 to 2.5 mol of a Mg compound in terms of MgO, 0 to 1.6 mol of a Ba compound in terms of BaCO3, 0.1 to 3.0 mol of a Ln (Ln includes two or three kinds of elements selected from Er, Dy, and Ho with Er being essential) compound in terms of Ln2O3, 0.01 to 0.4 mol of a Mn compound in terms of MnO4/3, 0.01 to 0.26 mol of a V compound in terms of V2O5, 0.3 to 3.5 mol of a Si compound in terms of SiO2, and 0.01 to 2.5 mol of an Al compound in terms of Al2O3 to 100 mol of barium titanate adjusted for a Ba/Ti molar ratio of 0.997 to 1.007.