Carrier membrane for piezoelectric transducer - having thermal expansion coefft near that of the piezoelectric material

摘要

Curving at elevated temps of a membrane carrying on one side a layer of a piezoelectric material is prevented by selecting the membrane material in such a manner that it shows a thermal expansion coefft. near that of the piezoelectric material. Prefd. membranes are 300 mu Al foil coated on both sides with 50 mu - thick hard eloxal layers (Al2O3); 260 mu thick Ti alloy foil (T2-Al-Mo-V); Vacodil membrane (RTM) N2-Fe alloy) and 200 mu thick mica plate.