EAGER: Parallelized Measurements of Kapitza Resistance

Grain boundaries are common in most metals and ceramics, and the orientation of the grain boundary can impact the ability of the material to conduct heat. Having a material with good heat conduction is useful in energy applications like ceramic fuels in nuclear reactors, thermoelectric generators, solid oxide fuel cells producing electricity from hydrogen, and polycrystalline diamond for high power electronics.

Measuring the thermal resistance at grain boundaries has been limited to slow, point-by-point measurements, resulting in not enough data to fully understand how the orientation of the grain boundary affects heat conduction. This project aims to develop a rapid, parallelized thermal resistance measurement device based on existing point-by-point technologies but applying it at 100 sites simultaneously.

This would increase the rate at which these measurements are done by 100x, shortening the time needed for measurements from several months to a couple of days. The proposed research can potentially transform the field of thermal measurements by enabling high-throughput approaches. In addition to the technical aspects, this project will engage graduate and undergraduate students with a special effort to recruit students from the university’s Women in Engineering group and provide demonstrations and lesson plans for local 4th grade classrooms.

If high-fidelity structure-property models for grain boundaries could be determined from a large data set, the thermal transport performance of nuclear fuels and other high value materials could be designed for enhanced energy production, reliability, and safety. The intellectual merit of this research is the potentially transformative nature of parallelized, microscopic thermal measurements.

Before this can be realized, the limitations of a parallelized implementation of thermoreflectance techniques need to be determined, as well as how well the properties of interest can be distinguished, such as individual grain thermal conductivity, grain boundary thermal resistance, and the role of defects within grains and near the grain boundaries on thermal transport.To resolve these issues and achieve the needed paradigm shift to a new class of high-throughput thermal characterization techniques, this EAGER project will focus on: (i) Developing a high-throughput thermal characterization device based on parallelization of a spatial domain, thermoreflectance method. (ii) Determining the measurement range and resolution of thermal contact resistances that can be detected with the proposed parallelized characterization technique.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.