Dielectric Ceramic Composition for Stable X7R MLCC Sintering
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Solution Overview
Problem
Current dielectric ceramic materials for multilayer ceramic capacitors (MLCCs) with base metal electrodes (BME) fail to maintain X7R or X7S temperature characteristics and reliability when sintered in reducing atmospheres, often resulting in reduced color and increased conductivity.
Innovation Solution
A dielectric ceramic composition comprising a barium titanate-based base material with specific subcomponents such as oxides and carbonates of variable valence acceptor elements (Mn, V) and rare earth elements (Dy), along with additional components like Ba, Ca, and Si, is used to ensure the dielectric constant remains between 2000 and 4000, and the surface color meets R≤30, G≤30, B≤40 criteria, even under reducing atmosphere conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric ceramic material with high donor content or no acceptor is sintered in reducing atmosphere, then the material exhibits semiconductivity characteristics with rapidly lowered resistance value, but the reliability and temperature characteristics (X7R/X7S) deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific acceptor elements (Mn: 0.01-0.50 wt%, V: 0.01-0.50 wt%, Cr: 0.01-0.50 wt%, Fe: 0.01-0.50 wt%) and adjusting the donor-acceptor ratio to maintain insulating properties in reducing atmosphere while achieving X7R/X7S temperature characteristics
Solution Approach 2:
The patent creates a composite dielectric ceramic system combining BaTiO3 base material with multiple dopant elements (donors like Nb, Ta and acceptors like Mn, V, Cr, Fe) to achieve synergistic effects that simultaneously provide X7R/X7S temperature stability and resistance to reducing atmosphere-induced semiconductivity
2Ease of manufacture
If a dielectric ceramic material is sintered in reducing atmosphere, then the surface color changes to dark blue or black, but the manufacturing precision and product quality control become difficult
Solution Approach 1:
The patent introduces specific color-stabilizing dopant elements (Cu: 0.01-0.50 wt%, Ni: 0.01-0.50 wt%, Co: 0.01-0.50 wt%, Zn: 0.01-0.50 wt%) that counteract the reducing atmosphere's effect on surface color, allowing the material to maintain consistent appearance despite sintering in reducing conditions
3Reliability
If the dielectric constant is increased to achieve high capacitance, then the capacitance value improves, but the temperature characteristics and reliability may be compromised
Solution Approach 1:
The patent optimizes the dielectric constant parameter to a specific range (2000-4000) by controlling dopant concentrations and donor-acceptor ratios, achieving a balance between high capacitance and stable temperature characteristics (X7R/X7S)
Solution Approach 2:
The patent employs a composite material system with BaTiO3 base and multiple functional dopants where donors (Nb, Ta) increase dielectric constant while acceptors (Mn, V, Cr, Fe) stabilize temperature characteristics, creating a synergistic composite that achieves both high capacitance and reliability
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 composition achieves reliable X7R or X7S temperature characteristics and improved reliability by maintaining the dielectric constant within the desired range and ensuring the Mean Time To Failure (MTTF) is 100 hours or more, while preventing surface color deviations and conductivity issues.
Implementation Method 1
A surface color of the body is R≤30, G≤30, B≤40 based on R/G/B
Implementation Method 2
a dielectric ceramic material in which an amount of an added donor is greater than an amount of an acceptor added to a BaTiO3-series base material, or a dielectric ceramic material to which no acceptor is added, is sintered at a reducing atmosphere, a specimen has a reduced color such as dark blue, black, or the like, and exhibits semiconductivity characteristics
Data Source
AI summary
A capacitor component includes: a body including a dielectric layer and an internal electrode layer; and an external electrode disposed on the body, and connected to the internal electrode layer. A surface color of the body is R≤30, G≤30, B≤40 based on R/G/B, and a dielectric constant of the dielectric layer is 2000 or more and 4000 or less.