On June 26 Carl Zweben presented a live webinar on Advanced Composite Thermal Management Materials and Applications.

Overview: This presentation covers key advanced composite thermal management materials and applications.  We also look at current and future advanced reinforcements, such as diamond particles, carbon nanotubes, graphene and graphite nanoplatelets.

The first of a new generation of advanced composite thermal materials, silicon carbide particle-reinforced aluminum (Al/SiC) was first used in thermal management by the speaker’s GE group in the 1980s.  It is now well established in a wide range of commercial and aerospace/defense applications.  There are now an increasing number of new composites with thermal conductivities up to ~1000 W/m-K, more than twice that of copper.  They also have low densities and low coefficients of thermal expansion (CTEs).  Some are cheaper than traditional materials.  Payoffs include: reduced component and system cost; reduced weight; increased reliability; reduced junction temperatures; increased power and light output; low-CTE, thermally conductive printed circuit boards (PCBs), potentially eliminating the need for underfill; CTE matching allows direct attach with hard solders, reducing thermal resistance and solder fatigue; and others.

Carl Zweben Ph. D.
Advanced Thermal Materials Consultant
Life Fellow, ASME; Fellow, SAMPE & ASM; Associate Fellow, AIAA

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Question and Answer Session

Question: A few months ago, I read an interesting article on aluminum impregnated SiC in some magazine – maybe Electronic Cooling or Design World or other.  Unfortunately, I lost the article and forgot the magazine or who wrote it.  It was by some US Al/SiC supplier.  I was hoping you might remember.  Or if you could send me the list of suppliers from your webinar, that would be appreciated.
Answer: Slide 32 has a list of Al/SiC suppliers.

Question: The thermal conductivity of diamond-Ag composites was quoted at 983W/mK.  This was sure news to me.  I was under the impression that an electrical insulator (diamond) was not compatible with an electrical conductor (Ag) in the conduction of heat because of the phonon scattering phenomena.  What am I missing?
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Question: Where can I get more information on advanced composite thermal management materials? What are the costs of the various materials you covered?
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Question: Are the carbon fibers used in aircraft like the Boeing 787 thermally conductive?
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Question: Are there ways to use some of the more expensive materials in cost-sensitive applications?
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Question: To what do you attribute the success of Al/SiC?
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Question: Al/SiC is an attractive material.  Is there a need for other new composites?
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Question: For the data from Eupec / Infineon, were the Si chips soldered directly to the AlSiC, or was the AlSiC coated or plated with another material to enable soldering?
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Question: What is the size of graphene sheets seen in the market?
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Question: Are there developments in low/tailorable CTE + high thermal conductivity but machinable composites?
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Question: What is the usual particle size in the state of the art thermal interface materials?
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Question: I’m very interested in anisoptropic materials. Is there some place I can get comprehenisive information on anisotropic thermally conductive composite materials?
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Question: I missed the material that had 1000 W/m-K isotropic thermal conductivity. What is its composition and who manufactures it?
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Question: Which type AlSiC cheaper than Cu?
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Question: What are your thoughts on new flip chip technologies and elimination of the IGBT base plate (i.e. soldering the flip chip directly to the PCB)?
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Question: How do the fatigue life properties of these materials compare to traditional materials like aluminum alloys?
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Question: I noticed that the thermophysical properties of thermal conductivity and density were addressed during the discussion. What about specific heat? Also, how does temperature dependency affect the thermal performance of these materials?
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Question: Would you have a supplier name and material name for the Carbon Fiber Injection molded material used in a laptop that replaced copper for its EM properties?
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Question: What specific material suggestions for high thermal conductivity and high electrical resistivity?
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Question: I had a question on the thermal conductivity of diamond-Ag composites, which was quoted at 983W/mK.  I was under the impression that an electrical insulator (diamond) was not compatible with an electrical conductor (Ag) in the conduction of heat because of the phonon scattering phenomena.  What am I missing?
To view the answer, click here.

Question: How do you use the specific heat?
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