Structure and low-temperature thermal conductivity of pyrolytic boron nitride

Publisher Website
Google Scholar
Abstract
The microstructure and morphology of three samples of pyrolytic boron nitride deposited at different temperatures have been characterized with use of x-ray diffraction and thermal-conductivity measurements. The x-ray analysis allowed the determination of the mean interlayer spacing, the out-of-plane coherence length, and the crystallites’ preferred orientation. It revealed the presence of three distinct morphologies. The thermal conductivity was measured as a function of temperature in the range 1.5<T<300 K. The temperature variations of the thermal conductivity were fitted by using a model previously developed for the analysis of the thermal conductivity of graphites and carbons. This fit allowed the determination of the in-plane coherence length. It also allowed the analysis of point-defect concentration and of the interlayer shear modulus. It is shown that low-temperature thermal-conductivity measurements may be used to complement x-ray diffraction data for the microstructural characterization of materials.