Oxide Composite Particles for High Thermal Conductivity
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Solution Overview
Problem
Current materials for high-frequency devices lack sufficient thermal conductivity while maintaining low dielectric constant and low dielectric loss tangent, particularly when used in resin compositions.
Innovation Solution
Oxide composite particles comprising 40-85% α-cristobalite, 5-50% α-alumina, and 10% or less mullite crystal phases, with an aluminum-to-silicon elemental ratio of 1.5 or more, produced by mixing silica and alumina particles and heating them between 1300-1500°C, are used in a resin composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spherical silica is used as a filler, then low dielectric constant and low dielectric loss tangent are achieved, but thermal conductivity remains insufficient
Solution Approach 1:
The invention uses a composite filler consisting of silica particles with an alumina coating layer. The silica core provides low dielectric constant and low dielectric loss tangent, while the alumina coating layer provides high thermal conductivity. This composite structure resolves the contradiction by combining materials with complementary properties to achieve both excellent dielectric performance and high thermal conductivity simultaneously.
2Temperature
If amorphous spherical silica is crystallized into quartz or cristobalite, then thermal conductivity is improved, but dielectric properties may deteriorate
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the core silica particles maintain their amorphous state for optimal dielectric properties, while the surface coating layer is crystallized alumina for high thermal conductivity. This local differentiation of crystalline state allows each material to contribute its best properties without compromising the other.
3Temperature
If alumina content is increased to improve thermal conductivity, then heat dissipation properties are enhanced, but dielectric loss tangent increases
Solution Approach 1:
The alumina is localized specifically in the coating layer on the surface of the silica particles, rather than being uniformly distributed throughout the filler. This localized placement allows the alumina to provide thermal conductivity enhancement at the particle surfaces and interfaces, while the bulk silica core maintains its excellent dielectric properties with low loss tangent.
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 resulting resin composition achieves high thermal conductivity, low dielectric constant, and low dielectric loss tangent, making it suitable for high-frequency substrates with improved heat dissipation properties.
Implementation Method 1
heating the mixture at 1300 to 1500° C. for 2 to 8 hours
Data Source
AI summary
Provided are oxide composite particles to be mixed with a resin to obtain a resin composition having high thermal conductivity, low dielectric constant, and low dielectric loss tangent. The oxide composite particles containing silica and alumina, in which the oxide composite particles contain 40 to 85% by mass of an α-cristobalite crystal phase, 5 to 50% by mass of an α-alumina crystal phase, and 10% by mass or less of a mullite crystal phase, and an elemental ratio of aluminum to silicon (aluminum/silicon) as determined by X-ray photoelectron spectroscopy is 1.5 or more.