Structure and Composition of Ba-W-Ti-O Ceramics Interface Regions Formed at Ultrasonic Vibration

The study of Ba-W-Ti-O ceramics has shown that the structure and composition of their interface regions differ from those in the grain bulk owing to the diffusion of tungsten atoms to the grain surface during sintering. They are determined by the conditions of compacting of dry nanopowders (compaction pressure and power of ultrasonic action) and vary in a nonmonotonic way. Increasing the pressure during dry static compacting and exposure to ultrasound result in the formation of a complex structure of fragments and boundaries between them, increasing the acoustic density and decreasing the intergranular boundary thickness. This affects the travel time of the phonon pulse through the sample, which allows one to determine the density and thickness of the grain boundaries by the method of phonon spectroscopy.