title: Local measurement of thermal conductivity and diffusivity.
abstract: Simultaneous measurement of local thermal diffusivity and conductivity is demonstrated on a range of ceramic samples. This was accomplished by measuring the temperature field spatial profile of samples excited by an amplitude modulated continuous wave laser beam. A thin gold film is applied to the samples to ensure strong optical absorption and to establish a second boundary condition that introduces an expression containing the substrate thermal conductivity. The diffusivity and conductivity are obtained by comparing the measured phase profile of the temperature field to a continuum based model. A sensitivity analysis is used to identify the optimal film thickness for extracting the both substrate conductivity and diffusivity. Proof of principle studies were conducted on a range of samples having thermal properties that are representatives of current and advanced accident tolerant nuclear fuels. It is shown that by including the Kapitza resistance as an additional fitting parameter, the measured conductivity and diffusivity of all the samples considered agreed closely with the literature values. A distinguishing feature of this technique is that it does not require a priori knowledge of the optical spot size which greatly increases measurement reliability and reproducibility.
authors.affiliation: Materials Science and Engineering Department, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415-2209, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Hurley
authors.affiliation: Materials Science and Engineering Department, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415-2209, USA.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Schley
authors.affiliation: Mechanical and Aerospace Engineering Department, The Ohio State University, 201 W. 19th Ave., Columbus, Ohio 43210, USA.
authors.forename: Marat
authors.initials: M
authors.lastname: Khafizov
authors.affiliation: Nuclear Science and Engineering, Idaho State University, 921 S. 8th Ave., Pocatello, Idaho 83209-8060, USA.
authors.forename: Brycen L
authors.initials: BL
authors.lastname: Wendt