Verfahren zur Herstellung eines pyro- oder piezoelektrischen Composites
Production of a piezoelectric or pyroelectric 0-3-composite with high filling content involves (a) emulsifying an aqueous solution, containing the desired ratio of ceramic cations, in an organic solvent under conditions which control the droplet size of the emulsified discontinuous aqueous phase; (b) adding a precipitant to precipitate the cations in the aqueous phase; (c) drying to remove the solvent and leave solid particles which are then calcined to ceramic powder in an oxygen-containing atmosphere; (d) mixing and homogenising the ceramic powder with an unset or partially set plastic material; and (e) moulding and optionally setting the plastic material. Preferably, the plastic material is an oligomeric elastomer. Also claimed is a pyroelectric or piezoelectric 0-3-composite produced by the above method and having a ceramic filling content of 70-90 vol.%. USE - The 0-3-composite is especially useful as a piezoelectric transducer for hydrophonics, for air ultrasonic transducers, for medical diagnostics and for non-destructive ultrasonic material testing or as a thin sensor element in pyroelectric detectors. ADVANTAGE - Composite, having high ceramic filling content and freely selectable composition, particle diameter and grain size, is produced simply.
DE 1997-19709184 A: 19970306