Dielectric Ceramic Composition for Low-Loss Co-Firing
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Solution Overview
Problem
Conventional forsterite-based dielectric ceramics exhibit high dielectric losses due to unreacted sintering aids and compromised mechanical strength when the amount of sintering aids is reduced, necessitating a solution that prevents unreacted sintering aids from remaining after firing while maintaining sinterability and mechanical strength.
Innovation Solution
A dielectric ceramic composition containing Mg2SiO4 as the main component, with zinc oxide and a glass component as additives, is fired at a temperature between 800°C to 1000°C in an oxygen atmosphere, ensuring a peak intensity ratio of X-ray diffraction peaks of zinc oxide to Mg2SiO4 is 10% or less, resulting in a relative density of 96% or greater, thereby reducing dielectric losses and enhancing mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amount of sintering aids is reduced to lower dielectric losses, then dielectric losses decrease, but mechanical strength deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the sintering aid system by replacing traditional zinc oxide-based sintering aids with a specific glass component containing Li2O (10-30 mass%), B2O3 (10-30 mass%), SiO2 (30-60 mass%), and Al2O3 (5-20 mass%). This compositional parameter change allows achieving complete reaction without residual sintering aids, thereby reducing dielectric losses while the glass component provides liquid phase sintering that maintains mechanical strength.
Solution Approach 2:
The patent creates a composite sintering aid system using a specific glass composition that combines multiple oxides (Li2O, B2O3, SiO2, Al2O3) to achieve synergistic effects. This composite glass component serves dual functions: it acts as a sintering aid that completely reacts to reduce dielectric losses, and simultaneously provides liquid phase sintering to maintain mechanical strength, resolving the contradiction between reducing dielectric losses and maintaining strength.
2Ease of manufacture
If sintering aids are used to maintain sinterability, then sinterability is maintained, but unreacted sintering aids remain causing high dielectric losses
Solution Approach 1:
The patent modifies the chemical composition parameters of the sintering aid to create a glass component with specific oxide ratios that enable complete reaction during sintering. The controlled composition ensures the glass component reacts fully with the forsterite base material, eliminating residual sintering aids that would otherwise cause high dielectric losses, while maintaining adequate sinterability through liquid phase formation.
Solution Approach 2:
The patent extracts and eliminates the problematic residual sintering aid phase from the final ceramic structure by designing a glass component composition that completely reacts during sintering. By removing the unreacted sintering aid phase (which causes high dielectric losses) while retaining the beneficial liquid phase sintering mechanism, the patent achieves low dielectric losses with maintained sinterability.
3Adaptability or versatility
If firing temperature is lowered to co-fire with Ag-based metals, then co-firing with conductor materials is enabled, but mechanical strength and sinterability are compromised
Solution Approach 1:
The patent changes the sintering behavior parameters by introducing a glass component with specific composition that becomes liquid at relatively low temperatures (below Ag melting point). This liquid phase enables sintering and bonding at lower temperatures, allowing co-firing with Ag-based conductor materials, while the glass component also provides strength through liquid phase sintering mechanisms.
Solution Approach 2:
The glass component acts as an intermediary substance that facilitates low-temperature co-firing between the forsterite dielectric and Ag-based conductor materials. The glass forms a liquid phase that promotes sintering and bonding at temperatures below the Ag melting point, enabling co-firing while maintaining mechanical strength through the liquid phase sintering mechanism.
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 results in a dielectric ceramic with improved dielectric properties, including a high Q factor and reduced dielectric loss, allowing for low-temperature co-firing with Ag-based metals while maintaining mechanical strength, suitable for high-frequency applications.
Implementation Method 1
a dielectric ceramic composition containing Mg2SiO4 as the main component, with zinc oxide and a glass component as additives, is fired at a temperature between 800°C to 1000°C
Implementation Method 2
ensuring a peak intensity ratio of X-ray diffraction peaks of zinc oxide to Mg2SiO4 is 10% or less
Data Source
AI summary
Provided is a dielectric ceramic that includes a main component which contains Mg2SiO4 and additives which contain a zinc oxide and a glass component, in which, in X-ray diffraction. The peak intensity ratio, IB/IA, of the X-ray diffraction peak intensity IB of zinc oxide remaining unreacted, for which 2θ is between 31.0° and 32.0° and between 33.0° and 34.0°, with respect to the peak intensity IA of Mg2SiO4 as the main phase, for which 2θ is between 36.0° and 37.0°, is 10% or less. The dielectric ceramic has a relative density of 96% or greater.