Evaluation of bond quality and heat transfer of Cu-based microchannel heat exchange devices

Metal-based microchannel heat exchangers (MHEs) promise high heat transfer coefficients together with mechanical robustness, and are of interest for a wide range of applications. Fabrication technologies capable of creating high-aspect-ratio microscale structures in metals such as Cu at low cost and high throughput are of particular interest. Likewise, simple and reliable bonding and assembly techniques are critical for building functional metal-based microfluidic devices. In this article, the authors report successful fabrication, bonding, and assembly of Cu-based MHE prototypes. Bonding of Cu specimens was achieved through Al thin foil intermediate layers. Quantitative evaluation of bond strengths was carried out as a function of various bonding parameters. Results of preliminary heat transfer testing carried out on assembled Cu-based MHE prototypes are reported.