b'Figure 1. Thermal conductivity of UB 2and UB 4on heating and cooling, calculated up to 1773 K from experimental thermal diffusivity and thermal expansion data, and literature values (UB 2 :[15,16] , UB 4 :[16]) for specific heat. Fits are also shown for UB 2and UB 4as well as reference data for UO 2[9].these numbers, the conductivity fit[13,14]. Therefore, a linear equation to the experimental data is shownwas used to describe the UB4 thermal in Figure 1. Studies in the literatureconductivity: show that UB 2is an electronic conductor [11] with no band gap [12] and therefore a strongwhere C and D are constants electronic contribution to the thermaldescribing the electronic contribution conductivity is anticipated. For theto the thermal conductivity. Fitting the thermal conductivity of UB 4 , a linearUB 4data to Equation 2 the following Wiedemann-Franz temperatureterms were obtained: C=4.57310-3 dependence is observed suggestingWm-1K-2 and D=1.333101 that electronic contributions areWm-1K-1, providing an R2=0.9960. dominant. Phonon contributionsThe fit based on Equation 2 is also appear to be negligible given theshown in Figure 1. The thermal purely linear relationship observed.conductivities of both UB 2and UB 4This is in accordance with literatureare expected to be impacted by the studies that report UB 4to be anpresence of the identified impurities, electronic conductor and a semimetalshown in Figure 1, however, this effect would be minimal given their low volume fraction. 62 2019|AFC ACCOMPLISHMENTS'