Expanded Foamed Graphite Film for Low-Pressure Thermal Interfaces
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Solution Overview
Problem
Current thermal interface materials, such as synthetic graphite films, face challenges with low out-plane compressibility, limited interface gap-filling ability, and high thermal resistance, which are exacerbated by the need for high pressure that can cause stress damage to chips and radiators during installation.
Innovation Solution
An expanded foamed graphite film is prepared through interlayer intercalation treatment and thickness-limited expansion and foaming, allowing for higher compressibility, improved interface bonding, and enhanced thermal conductivity under low pressure, achieved by controlling the expansion ratio and using specific intercalators like hydrogen peroxide or metal salts to generate gas and create a hollow structure with increased surface roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high pressure (700 kPa) is applied to achieve low thermal resistance, then thermal resistance is reduced, but stress damage occurs to chips during installation
Solution Approach 1:
The invention changes the physical and chemical parameters of the graphite film through intercalation treatment with oxidizing agents (such as potassium permanganate and sulfuric acid), which expands the interlayer spacing and creates a more flexible structure. This allows the graphite film to achieve good thermal contact and low thermal resistance under low pressure conditions, eliminating the need for high pressure (700 kPa) that would cause stress damage to chips.
2Temperature
If synthetic graphite film is used to improve thermal conductivity, then in-plane thermal conductivity is enhanced, but out-plane compressibility remains low
Solution Approach 1:
The invention applies local quality changes by performing intercalation treatment on the graphite film structure, specifically expanding the interlayer spacing through chemical treatment with oxidizing agents. This creates regions with enhanced out-of-plane compressibility while preserving the in-plane thermal conductivity of the graphite structure, achieving both thermal performance and mechanical compliance.
Solution Approach 2:
The invention creates a composite structure by intercalating oxidizing agents into the graphite film, forming a composite material with improved properties. The intercalated compounds (such as graphite intercalation compounds with metal oxides or hydroxides) provide enhanced compressibility in the out-of-plane direction while maintaining the thermal conductivity pathways in the in-plane direction.
3Ease of operation
If graphite film is expanded and foamed to improve compressibility, then interface gap-filling ability is enhanced, but manufacturing precision becomes difficult to control
Solution Approach 1:
The invention performs preliminary intercalation treatment before the final foaming/expansion process. By pre-expanding the interlayer spacing through chemical treatment, the graphite film is prepared in advance to accept controlled foaming, which results in more uniform expansion and better manufacturing precision during the subsequent thickness-limited expansion process.
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 method results in a graphite film with high compressibility, low thermal resistance, and excellent thermal conductivity, effectively addressing the limitations of existing materials by allowing stable embedding under low pressure without causing stress damage, while maintaining mechanical properties and improving heat conduction both vertically and horizontally.
Implementation Method 1
the intercalator is thermally decomposed to generate gas, and the graphite film is expanded in the expansion and foaming process
Implementation Method 2
the intercalator is thermally decomposed to generate gas, and the graphite film is expanded in the expansion and foaming process
Data Source
AI summary
A method for preparing expanded foamed graphite film includes the following steps: Step A: impregnating a synthetic graphite film into an intercalator for an interlayer intercalation treatment to prepare an intercalated graphite film; Step B: performing a thickness-limited expansion and foaming to the intercalated graphite film obtained in Step A, with an expansion ratio y of 2-25, to obtain an expanded foamed intercalated graphite film.