Synthesis, characterization, and thermal properties of ceramic-fullerene thin films
Mayeaux, Brian Mitchell
Barrera, Enrique V.
Doctor of Philosophy
Thin films containing ZrO2 and dispersed fullerenes have been synthesized using codeposition processing, and the role that dispersed fullerenes play in the thermal behavior of co-deposited films has been characterized. The presence of C60 within the films has been confirmed using a new application of electron impact mass spectrometry, and the structure and stability of dispersed C60 in Zr and ZrO2 have been studied using Raman spectrometry, TEM, XRD, and WDS. Strong interactions between neighboring ZrO2 grains and dispersed C60 are manifested in the decreased desorption rate of C60 from the ZrO2 surface, and effects of dispersed C60 on the ZrO2 microstructure are observed using TEM. The potential for the use of fullerenes and fullerene-like structures in thermal barrier applications has been examined using both steady state and transient thermal conductivity measurement methods to measure the effective film conductivity. Significant reductions have been observed in the co-deposited film conductivity due to the contact resistance between dispersed fullerenes and neighboring ZrO2 grains, and contributions of fullerenes and the affected grain boundary region to thermal conductivity reductions have been identified. Dispersed C60 is proposed to affect phonon scattering in ZrO2 by imposing an interfacial resistance that is strongly dependent upon fullerene particle size, shape, and distribution.
Engineering; Materials science