Multi-Layer Ceramic Component Grain Boundary Control
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Solution Overview
Problem
Multi-layer electronic components used in high-frequency piezoelectric devices and transducers face challenges in durability under high voltage, high temperature, and high humidity conditions, particularly in automotive applications, due to limitations in heat resistance and humidity resistance.
Innovation Solution
The development of multi-layer electronic components with sintered dielectric material layers having a perovskite structure that includes Pb, where the lead compound at crystal grain boundaries is controlled to minimize grain size and concentration, and the use of a two-step firing process to enhance strength and prevent moisture infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional single-step firing process is used to manufacture multi-layer electronic components, then manufacturing simplicity is maintained, but heat resistance and humidity resistance are insufficient for high-temperature automotive applications
Solution Approach 1:
The single-step firing process is segmented into two distinct steps: first firing at 900-1000°C to form initial structure, then second firing at 1000-1100°C to enhance sintering and reduce lead compound grains. This segmentation allows each step to optimize specific properties, achieving high heat and humidity resistance that cannot be obtained through single-step firing.
Solution Approach 2:
The invention changes the firing parameters by introducing a temperature gradient between two firing steps. The first firing establishes the basic ceramic structure, while the second firing at higher temperature reduces the size of lead compound grains at grain boundaries to 0.01μm or less, thereby improving reliability without excessive complexity.
2Strength
If lead compound grains at crystal grain boundaries are not controlled, then manufacturing process is simpler, but component strength and durability under high voltage and humidity deteriorate
Solution Approach 1:
The invention achieves precise control of lead compound grain size by optimizing the second firing temperature (1000-1100°C) and duration (1-3 hours). This parameter optimization reduces lead compound grains to 0.01μm or less, preventing moisture infiltration and enhancing component strength and durability under high voltage and humidity conditions.
Solution Approach 2:
The invention uses a liquid phase sintering mechanism where lead compounds form a liquid phase during firing that fills grain boundaries. By controlling the cooling rate and firing parameters, the liquid phase solidifies into fine-grained structures, achieving precise grain size control without complex mechanical intervention.
3Reliability
If conventional firing atmosphere is used, then manufacturing process is simpler, but moisture infiltration and degradation under high humidity conditions occur
Solution Approach 1:
The invention employs a controlled firing atmosphere that creates an environment resistant to moisture infiltration. The second firing at 1000-1100°C in a controlled atmosphere reduces lead compound grains and creates a dense ceramic structure that prevents moisture penetration, thereby achieving high humidity resistance.
Solution Approach 2:
The invention converts the potentially harmful lead compounds, which normally remain as large grains and facilitate moisture infiltration, into beneficial fine-grained structures through controlled second firing. This transforms the harmful presence of lead compounds into a protective feature that enhances humidity resistance.
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 solution provides high-strength, high-reliability components that can withstand repetitive operation under high voltage, high temperature, and high humidity conditions, with improved heat resistance and humidity resistance, suitable for automotive applications.
Implementation Method 1
a plurality of dielectric material layers made of a sintered material having perovskite structure that includes Pb
Implementation Method 2
the number of grains of the lead compound not smaller than 0.01 μm are 2 or less per 100 μm2 on average
Data Source
AI summary
A multi-layer electronic component that can be repetitively operated under high voltage, high temperature and high humidity is provided. The multi-layer electronic component comprises a plurality of dielectric material layers made of a sintered material having perovskite structure that includes Pb; and a plurality of internal electrodes, the dielectric material layers and the internal electrodes being stacked alternately one on another, wherein lead compound that remains in the crystal grain boundaries of the dielectric material layers is controlled so that the number of grains of the lead compound not smaller than 0.01 μm are 2 or less per 100 μm2 on average.