Systematic experimentation on grain-boundary sliding of ceramics with a glassy film at grain boundaries has been carried out by low-frequency internal friction technique up to =2200K. A model silicon nitride polycrystal was selected for this basic investigation in which the grains were continuously encompassed by a nanometre-sized film of pure SiO, glass. The SiO, film was also doped with incre...

We have studied the internal friction of amorphous diamond-like carbon films prepared by pulsed-laser deposition from 0.4 to 300K. The low temperature internal friction below 10K is dominated by the atomic tunnelling states for amorphous solids, which is a measure of structure disorder. We have tried to vary the content of sp carbon atoms versus sp ones by changing laser fleunce, by doping with...

The ultrasonic low-frequency coupling method was used to study the relaxation processes in cold worked and annealed lead, in particular the Bordoni relaxation. New high-temperature signatures were observed in 5N lead on each temperature side of the high-frequency Bordoni peak. The signatures, measured in a temperature range where a non-negligible internal friction background is observed at low ...