Thermal diffusivity of particulate composites made from aluminum oxide and nickel aluminide by a photothermal deflection technique

The photothermal deflection technique is used to measure the thermal diffusivity of a metal-ceramic composite. The present, as well as other data on composites are analyzed to estimate a value for the Kapitza radius, r(k), which represents the effective value of the thermal boundary resistance of heterointerfaces. Remarkably, the data from different metal-ceramic composite materials lead to a similar value (within a factor of about two), r(k) approximate to 1 mu m. Possible reasons for this outcome are discussed in terms of the acoustic mismatch model for thermal boundary resistance. Analysis of the data also suggests possible anomalous effects in nanostructured materials. (C) 1997 Acm Metallurgica Inc.