Investigation of nanoceramics based on aluminum and zirconium oxides usingthe heat pulse method

The processes of phonon transport in ceramics and composites based on alumi num and zirconium oxides are studied experimentally in the region of helium temperatures. It is demonstrated that, for the ceramic grain size R within two orders of magnitude and more (up to nanosizes), the phonon diffusion c oefficient D-eff proportional to R and exhibits a decreasing temperature de pendence. In aluminum-based nanoceramics with R < 200 nm, the phonon diffus ion coefficient decreases abruptly by two orders of magnitude, and its temp erature dependence becomes increasing. A model of temperature dependence of the diffusion coefficient is suggested. (C) 2001 MAIK "Nauka/ Interperiodi ca".