Ni Electrode Paste for Thin Multilayer Ceramic Capacitors
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in achieving high electrostatic capacity due to issues with Ni internal electrode continuity and coverage rate, which are affected by the sintering suppression effect and bondability between Ni electrodes and dielectric layers, often resulting in sparse conductor structures and reduced capacity when attempting to reduce thickness and increase layers.
Innovation Solution
A conductor paste comprising Ni as the main ingredient with a second ingredient having a melting point of 1490°C or more, such as Cr, Mo, or W, is used, with a fine particle size and specific amount to improve the continuity and coverage rate of internal electrode layers, allowing for further reduction in thickness without compromising electrostatic capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of co-material (dielectric material) added to the conductor paste is increased to suppress Ni grain growth and improve bondability, then sintering suppression effect and bondability are improved, but the continuity of Ni internal electrodes deteriorates, causing sparse conductor structure and reduced coverage rate
Solution Approach 1:
The invention changes the particle size parameter of the co-material from conventional large sizes to fine particles (0.1-10 μm, preferably 0.5-5 μm). This parameter change allows the co-material to effectively suppress Ni grain growth and improve bondability while maintaining Ni electrode continuity, as fine particles distribute more uniformly and create fewer discontinuities in the conductor structure.
Solution Approach 2:
The invention uses a composite material system consisting of Ni powder combined with fine dielectric material particles (such as barium titanate, strontium titanate, or calcium zirconate) with specific particle sizes. This composite approach enables both sintering suppression and continuity maintenance by optimizing the interaction between the conductive Ni phase and the dielectric co-material phase at the microstructural level.
2Quantity of substance
If the thickness of internal electrodes and dielectric layers is reduced and the number of layers is increased to achieve larger electrostatic capacity with smaller size, then the electrostatic capacity is improved, but more co-material has to be added to the conductor paste, which deteriorates the continuity of internal electrodes
Solution Approach 1:
The invention changes the particle size parameter of the co-material to fine ranges (0.1-10 μm) which enables effective sintering suppression at lower addition amounts. This allows the device to achieve high electrostatic capacity through increased layer count and reduced thickness without requiring excessive co-material addition that would compromise electrode continuity.
3Reliability
If conventional large particle size co-material is used in the conductor paste, then the sintering suppression effect is achieved, but the continuity of internal electrodes deteriorates and coverage rate drops
Solution Approach 1:
The invention fundamentally changes the particle size parameter of the co-material from conventional large sizes (>10 μm) to fine particles (0.1-10 μm, preferably 0.5-5 μm). This parameter change resolves the contradiction by enabling effective sintering suppression through uniform distribution and numerous contact points, while maintaining electrode continuity due to the fine scale of particles relative to the electrode structure.
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 enhances the continuity and coverage rate of internal electrode layers, enabling a multilayer ceramic electronic device with improved electrostatic capacity and reduced thickness, while preventing cracking and maintaining electrode continuity.
Implementation Method 1
firing this and forming a pair of external end electrodes at the two ends of the pre-firing element body
Implementation Method 2
to suppress grain growth of Ni due to firing, that is, to impart an Ni sintering suppression effect
Implementation Method 3
the pre-firing dielectric layers and pre-firing internal electrode layers are simultaneously fired
Data Source
AI summary
A multilayer ceramic capacitor 1 having dielectric layers 2 and internal electrode layers 3 formed using a conductor paste, wherein the conductor paste contains a conductive material, the conductive material is comprised of a first ingredient and second ingredient, the first ingredient includes metal elements having Ni as a main ingredient, and the second ingredient includes a metal element dissolving in the first ingredient and having a melting point of 1490° C. or more.