Laminated Ceramic Capacitor Moisture Resistance
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Solution Overview
Problem
Laminated ceramic capacitors with dielectric ceramics based on (CaxSr1−x)O]m[(TiyZr1−y)O2 suffer from insufficient lifetime characteristics in moisture resistance loading tests due to increased residual stress and internal electrode defects.
Innovation Solution
A laminated ceramic capacitor with a perovskite-type compound composition containing Ca, Zr, Sr, Ti, Si, Mn, and Al, where the total content of Zr and Ti is 100 parts by mol, and the molar ratios of Ca, Sr, and Ba are within specific ranges, along with internal electrodes made of Ni or Ni alloys, to reduce residual stress and enhance moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dielectric layer thickness is reduced to increase capacitance and reduce size, then the capacitance and miniaturization are improved, but the electric field intensity per layer increases and reliability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic by adding specific amounts of SiO2 (0.5-10 mol%), MnO (0.2-5 mol%), and Al2O3 (0.1-10 mol%) to the base (CaxSr1−x)O]m[(TiyZr1−y)O2] system. These compositional adjustments modify the material properties to reduce residual stress and prevent internal electrode defects, thereby maintaining reliability even when layer thickness is reduced for higher capacitance
Solution Approach 2:
The patent creates a composite dielectric ceramic system by combining the base (CaxSr1−x)O]m[(TiyZr1−y)O2] perovskite structure with accessory constituents (SiO2, MnO, Al2O3). This composite approach allows the material to benefit from both the high capacitance characteristics of the base system and the stress-reducing, reliability-enhancing properties of the added components
2Quantity of substance
If the dielectric layer thickness is reduced to increase capacitance and reduce size, then the capacitance and miniaturization are improved, but the electric field intensity per layer increases and manufacturing precision becomes more difficult to maintain
Solution Approach 1:
The patent adjusts the chemical composition parameters by incorporating SiO2, MnO, and Al2O3 in specific ranges, which modifies the sintering characteristics and mechanical properties of the dielectric ceramic. These parameter changes enable better bonding between the dielectric layer and internal electrodes, reducing peeling defects even when manufacturing extremely thin layers for high capacitance applications
Data Source
AI summary
As a dielectric ceramic constituting dielectric layers of a laminated ceramic capacitor, a dielectric ceramic is used which contains, as its main constituent, a perovskite-type compound containing Ca and Zr and optionally containing Sr, Ba, and Ti, and further contains Si, Mn, and Al, and when the total content of Zr and Ti is regarded as 100 parts by mol, the total content (100×m) of Ca, Sr, and Ba meets 1.002≦m≦1.100 in terms of parts by mol, the Si content n meets 0.5≦n≦10 in terms of parts by mol, the Mn content u meets 0.5≦u≦10 in terms of parts by mol, and the Al content w meets 0.02≦w≦4 in terms of parts by mol, m and n satisfying −0.4≦100(m−1)−n≦3.9.