Non crystalline ceramics have more phonon scattering rates (e.g., due to phonon-grain boundary scattering mechanism). Therefore, their thermal conductivity is usually less than crystalline ceramics.
Non crystalline ceramics have more phonon scattering rates (e.g., due to phonon-grain boundary scattering mechanism). Therefore, their thermal conductivity is usually less than crystalline ceramics.
a resistance arises from the disturbance of a periodic potential.
Crystalline matter has a periodic potential. Therefore, diamant has a high thermal conductivity. If you generate grain boundaries, then the periodic potential is disturbed. This effects a backscattering of phonons and therefore a thermal resistance.