Ceramic Composition with Li2O-B2O3 Sintering Agents for Low Loss
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Solution Overview
Problem
Conventional ceramic compositions containing diopside or tungsten bronze pseudo-solid solutions as main phase components face challenges in achieving low dielectric loss and high-frequency performance, while also requiring sintering at low temperatures and maintaining adequate flexural strength.
Innovation Solution
A ceramic composition with a diopside or tungsten bronze pseudo-solid solution as the main phase component, incorporating Li2O and B2O3 as sintering agents, where the Li content is higher than the B content to reduce dielectric loss and improve the Q value, with specific mass ratios and additives like SrTiO3 to enhance sinterability and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If Li2O and B2O3 are used as sintering agents to enable low-temperature sintering, then sintering temperature is reduced, but dielectric loss increases
Solution Approach 1:
The patent changes the chemical composition parameters of the sintering agent by specifying that Li2O content is 0.5-2.0 mass% and B2O3 content is 0.1-0.5 mass%, with Li2O/B2O3 ratio controlled at 1.0-5.0. This precise parameter control optimizes the liquid phase viscosity during sintering, allowing low-temperature sintering while minimizing dielectric loss in the finished product.
Solution Approach 2:
The patent uses a composite sintering agent system combining Li2O and B2O3 in specific proportions rather than relying on a single oxide. This composite approach creates a synergistic effect where Li2O provides low-temperature sintering capability while B2O3 controls liquid phase viscosity, together achieving both low sintering temperature and low dielectric loss.
2Loss of energy
If sintering is performed at high temperature to reduce dielectric loss, then dielectric loss is reduced, but low-resistance metal diffuses into the substrate material
Solution Approach 1:
The patent changes the sintering temperature parameter to a specific range (900-1100°C) that is low enough to prevent metal diffusion but high enough to achieve proper sintering when Li2O-B2O3 sintering agents are used. This temperature parameter optimization resolves the contradiction between reducing dielectric loss and preventing metal diffusion.
3Loss of energy
If Li content is increased to reduce dielectric loss, then dielectric loss is reduced, but flexural strength degrades
Solution Approach 1:
The patent optimizes the Li2O content parameter to a specific range (0.5-2.0 mass%) rather than using excessive amounts. This controlled parameter change ensures sufficient Li2O for low-temperature sintering and low dielectric loss while preventing over-sintering that would degrade flexural strength. The B2O3 content is simultaneously optimized to reinforce the structure.
Solution Approach 2:
The patent employs a composite additive system of Li2O and B2O3 where Li2O (0.5-2.0 mass%) provides sintering assistance and B2O3 (0.1-0.5 mass%) provides structural reinforcement. This composite approach balances dielectric loss reduction with flexural strength maintenance, as B2O3 compensates for the potential strength degradation caused by Li2O.
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 ceramic composition achieves reduced dielectric loss, improved Q value, and suppressed flexural strength degradation, enabling efficient high-frequency performance and low-temperature sintering, while maintaining adequate mechanical strength.
Implementation Method 1
Li and B components act as sintering agents when a ceramic material is sintered to obtain a sintered compact of the ceramic composition. Ceramic materials containing Li and B components can be sintered at a low temperature.
Implementation Method 2
it was found that the high viscosity of the liquid phase of the sintering agent significantly inhibited the growth of the main crystal during sintering
Implementation Method 3
The sintering agent is deposited around the main phase crystal or on the grain boundary within the main phase crystal that has grown large
Data Source
AI summary
A ceramic composition according to an embodiment of the present invention contains: a main phase component represented by CaMgSi2O6 or Ba4(Re(1-x), Bix)9.33Ti18O54; and an additive component containing a Li component and a B component, An observation field, a part of a sectional surface of the ceramic composition, is divided into a plurality of unit observation regions. Among all the unit observation regions, those containing no or little sintering agent component are referred to as the main crystal regions. An area percentage of main crystal regions relative to the observation field is 30% or more, the main crystal regions being the unit observation regions containing 0.5% or less by area of the additive component.