Dielectric Ceramic Composition for High-Reliability Monolithic Capacitors
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Solution Overview
Problem
Monolithic ceramic capacitors face reliability issues when subjected to high electric fields over long periods under high-temperature conditions, requiring improved dielectric ceramics with enhanced insulation resistance.
Innovation Solution
A dielectric ceramic composition featuring barium titanate with a perovskite structure, incorporating rare earth elements, nickel, and titanium as secondary phase particles, with specific molar ratios of nickel to rare earth elements and nickel to magnesium, forming a crystalline compound oxide that maintains high insulation resistance under high electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the thickness of dielectric ceramic layers is reduced to increase capacitance and decrease size, then the electric field applied to the dielectric ceramic layers increases, but reliability under high-temperature load deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic by incorporating specific rare earth elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu) at controlled concentrations (0.01-5 mol%) along with Mg (0.1-5 mol%) and Ni (0.1-5 mol%). This compositional parameter change modifies the material's electrical and thermal properties to maintain reliability under high electric fields while enabling thinner layer structures.
Solution Approach 2:
The patent creates a composite dielectric ceramic system by combining barium titanate-based main phase with secondary phases containing rare earth elements, Mg, and Ni. This composite structure leverages the beneficial properties of each component: the high permittivity of barium titanate, the stability provided by rare earth elements, and the electrical property enhancement from Mg and Ni, achieving both high capacitance density and reliability.
2Volume of moving object
If higher electric fields are applied to achieve compact capacitor design, then size is reduced, but insulation resistance decreases over time under high-temperature conditions
Solution Approach 1:
The patent introduces sacrificial secondary phases (rare earth-Mg-Ni crystalline compounds) that preferentially undergo degradation or form protective barrier layers at grain boundaries under high electric field stress. These phases act as 'sacrificial' elements that protect the main dielectric phase from breakdown, maintaining insulation resistance even when subjected to high fields for compact design.
Solution Approach 2:
The patent incorporates rare earth elements and specific metal combinations that form stable crystalline secondary phases beforehand, which serve as pre-formed protective structures. These phases cushion against the detrimental effects of high electric fields by stabilizing grain boundaries and preventing defect formation, thereby maintaining insulation resistance stability over time under high-temperature load.
Data Source
AI summary
A dielectric ceramic contains a barium titanate compound oxide as a main component; at least one rare earth element R selected from Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu; Mg; and Ni, such that a crystalline compound oxide containing the rare earth element R, Ni, and Ti as main components is present. Dielectric ceramic layers are made of the dielectric ceramic. Accordingly, even when a higher electric field is continuously applied under a high-temperature atmosphere for a long time, high reliability can be ensured.