Dielectric Ceramic Composition Core-Shell Boundary R Element Concentration
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Solution Overview
Problem
Existing dielectric ceramic compositions struggle to combine high specific permittivity and reliability, particularly in multilayer ceramic capacitors, due to challenges in distributing rare-earth elements effectively within the dielectric particle core-shell structure.
Innovation Solution
A dielectric ceramic composition with a perovskite-type crystal structure, featuring a core-shell structure where the 'R' element is maximally concentrated at the boundary region between the core and shell, with a controlled diffusion state to achieve high specific permittivity and reliability, using a compound formula ABO3 and incorporating oxides of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare-earth elements are distributed throughout the shell portion with gradual increase towards crystal grain boundary, then reliability is improved, but specific permittivity cannot be sufficiently enhanced
Solution Approach 1:
The patent applies local quality by concentrating the rare-earth element R at the boundary region between core and shell, creating a specific compositional distribution where the boundary region has highest R content, the shell has intermediate content, and the core has lowest or no R content. This localized concentration at the boundary maximizes the synergistic effect between donor-type and acceptor-type elements, achieving both high specific permittivity (3000 or more) and good reliability simultaneously
2Ease of manufacture
If rare-earth elements are diffused in the main component with higher concentration inside diffusion layer, then manufacturing is simplified, but specific permittivity and reliability cannot be fully combined
Solution Approach 1:
The patent achieves the local quality principle by establishing a three-zone compositional structure: core region with little or no R element, shell portion with intermediate R element concentration, and boundary region with maximum R element concentration. This specific spatial distribution of R element cannot be achieved by simple diffusion alone, requiring controlled processing to create the gradient structure that maximizes both specific permittivity and reliability
Data Source
AI summary
A dielectric ceramic composition comprising a compound expressed by a formula of ABO3, where “A” is Ba alone, or Ba and at least one selected from Ca and Sr, and “B” is Ti alone, or Ti and Zr, and having a perovskite-type crystal structure, and an oxide of a rare-earth element including Sc and Y. The dielectric ceramic composition includes a dielectric particle having a core-shell structure which has a core and a shell, the shell being present around the core and including at least “R” element, and in the shell, a region showing a maximum content rate of “R” element is a boundary region between the core and the shell.