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 d iffusivity of a metal-ceramic composite. The present, as well as other data on composites are analyzed to estimate a value for the Kapitza r adius, r(k), which represents the effective value of the thermal bound ary resistance of heterointerfaces. Remarkably, the data from differen t 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 fo r thermal boundary resistance. Analysis of the data also suggests poss ible anomalous effects in nanostructured materials. (C) 1997 Acm Metal lurgica Inc.