Improving contact resistance in metal–ceramic heat exchangers running liquid metal by additive manufacturing and ceramic tubes with electroplated films

In the search for thermal management of advanced avionics packaging, materials such as eutectic liquid metal (LM) alloys and synthetic ceramics with superior thermophysical properties offer reliable and effective solutions. Conductive ceramic tubes can be used to contain LM as a coolant for heat exc...

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Bibliographic Details
Published in:	International journal of advanced manufacturing technology 2021-04, Vol.113 (7-8), p.2101-2119
Main Authors:	Armen, Jerald, Bruck, Hugh A.
Format:	Article
Language:	eng
Subjects:	Additive manufacturing Avionics CAE) and Design Ceramic powders Ceramics Cermets Computer-Aided Engineering (CAD Conductivity Contact resistance Embedding Engineering Heat exchangers Industrial and Production Engineering Laser sintering Liquid metals Machining Mechanical Engineering Media Management Metal powders Optimization Original Article Packaging Plates Prefabrication Rapid prototyping Surface defects Surface roughness Thermal management Thermophysical properties Tolerances Tubes Wettability
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Tags:	Add Tag 3d 1 ceramic-metal 1 printing 1

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Summary:	In the search for thermal management of advanced avionics packaging, materials such as eutectic liquid metal (LM) alloys and synthetic ceramics with superior thermophysical properties offer reliable and effective solutions. Conductive ceramic tubes can be used to contain LM as a coolant for heat exchangers. However, conductive ceramics will still need to be combined with metals to provide optimal thermal and structural performances. Additive manufacturing (AM) technologies have also shown they can facilitate novel approaches for fabricating efficient multi-material structures. Recently, we developed an in situ AM approach for embedding prefabricated components, such as ceramic tubes, inside a metallic block without parting surfaces for better sealing and more intimate contact between the metal and ceramic. In this selective laser sintering (SLS) approach, metal powders are melted near embedded ceramic tubes to close interfacial gaps associated with surface roughness and machining tolerances, resulting in a contact resistance at the metal–ceramic interface that is reduced relative to conventional packaging approaches. In this paper, we demonstrate how metallic cold plates can be fabricated with improved power dissipation by encapsulating highly conductive ceramic tubes with a SLS metal structure. To optimize the adhesion of the melt pool, the surface of the ceramics is electroplated to reduce surface defects and chemistry in order to improve the wettability of the ceramic. Experimental results of the cold plate prototypes fabricated by in situ AM technique revealed up to a 1.6× improvement in heat transfer compared to cold plates packaged by a conventional assembly technique, and results are validated through further numerical and analytical approaches.
ISSN:	0268-3768 1433-3015