Graphite-Copper Heat Sink Composite With Thin Copper Layers
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Solution Overview
Problem
Existing graphite-copper composite materials do not achieve the desired high and stable thermal conductivity required for advanced technologies like IoT and electric vehicles, due to issues with copper's thermal expansion coefficient and impurities hindering conductivity.
Innovation Solution
A graphite-copper composite material is produced using pretreated scaly graphite particles and copper particles with a median diameter of 1.5 μm or less, with a copper layer thickness of 15 μm or less, and controlled impurity levels, sintered via a multiaxial electric current method to ensure close contact and reduced interfacial gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the copper layer thickness is reduced to improve thermal conductivity, then thermal conductivity increases, but mechanical strength deteriorates
Solution Approach 1:
The invention optimizes the copper layer thickness parameter to 15 μm or less, and controls copper particle median diameter to 1.5 μm or less, achieving a balance between thermal conductivity and mechanical strength through precise parameter control rather than extreme values
Solution Approach 2:
The invention creates a composite structure with scaly graphite particles and copper layer, where the graphite provides mechanical strength and the copper provides thermal conductivity, achieving synergistic effects that resolve the contradiction between the two properties
2Reliability
If copper particle size is reduced to improve thermal conductivity, then thermal conductivity increases, but manufacturing precision deteriorates
Solution Approach 1:
The invention specifies copper particles with median diameter of 1.5 μm or less, using precise parameter control to achieve high thermal conductivity while maintaining manufacturability through defined particle size distributions
Solution Approach 2:
The invention uses copper particles of specific size ranges (median diameter 1.5 μm or less) to create localized optimal thermal conduction paths while maintaining overall structural integrity and manufacturability
3Reliability
If the interfacial gap is reduced to improve thermal conductivity, then thermal conductivity increases, but manufacturing complexity increases
Solution Approach 1:
The invention controls the interfacial gap parameter to 150 nm or less through optimization of the copper layer and graphite particle interface, achieving high thermal conductivity while managing manufacturing complexity through defined structural parameters
4Reliability
If copper volume fraction is increased to improve thermal conductivity, then thermal conductivity increases, but thermal expansion coefficient increases
Solution Approach 1:
The invention optimizes the copper volume fraction to 3-20%, finding the optimal range that provides sufficient thermal conductivity while limiting the thermal expansion coefficient increase, demonstrating parameter optimization to resolve the contradiction
Solution Approach 2:
The invention uses a composite of scaly graphite particles and copper layer where graphite (with low thermal expansion) compensates for copper's high thermal expansion, allowing copper volume fraction to be optimized for thermal conductivity while maintaining stable thermal expansion characteristics
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 composite material achieves a thermal conductivity of 750 W/(m·K) or more with a low standard deviation, high flexural strength, and a low thermal expansion coefficient, suitable for high-performance electronic components.
Implementation Method 1
a step of sintering a molded body obtained by molding the molding raw material by a multiaxial electric current sintering method
Data Source
AI summary
A graphite-copper composite material that includes a copper layer having an average thickness of 15 μm or less and scaly graphite particles laminated with the copper layer interposed therebetween. The graphite-copper composite material has a copper volume fraction of 3 to 20%. The graphite-copper composite material further has: (A) copper crystal grains of the copper layer having an average grain size of 2.8 μm or less, a mass fraction of Al of less than 0.02%, and a mass fraction of Si of less than 0.04%, or (B) an interfacial gap of the copper layer and the scaly graphite particles of 150 nm or less.