Method for manufacturing a piezoelectric composite material

This process consists in making the composite material from a mixture of powder of piezoelectric ceramic of a particle size less than 400 m and of a hardenable liquid dielectric binder placed, during hardening of the binder, in a mould provided with orifices 44 for liquid overflow and installed between the plates 45, 46 of a press exerting on it a pressure greater than 40 bars. The figure gives an example of mould for making a piezoelectric composite disc according to the method. This mould, placed between the plates 45, 46 of a press, comprises an annular lateral wall 41, a matching bottom 42 and a lid 43 fitted with orifices 44 for liquid overflow. By virtue of the method, a piezoelectric composite material is obtained which is particularly advantageous for making a piezoelectric sensor sensitive to hydrostatic pressures. CE PROCEDE CONSISTE A REALISER LE MATERIAU COMPOSITE A PARTIR D'UN MELANGE DE POUDRE DE CERAMIQUE PIEZO-ELECTRIQUE DE GRANULOMETRIE INFERIEURE A 400MM ET D'UN LIANT DIELECTRIQUE LIQUIDE DURCISSABLE PLACE, PENDANT LE DURCISSEMENT DU LIANT, DANS UN MOULE POURVU D'ORIFICES 44 DE TROP-PLEIN DE LIQUIDE ET INSTALLE ENTRE LES PLATEAUX 45, 46 D'UNE PRESSE EXERCANT SUR LUI UNE PRESSION SUPERIEURE A 40BARS. LA FIGURE DONNE UN EXEMPLE DE MOULE POUR LA REALISATION D'UN DISQUE COMPOSITE PIEZO-ELECTRIQUE SELON LE PROCEDE. CE MOULE, PLACE ENTRE LES PLATEAUX 45, 46 D'UNE PRESSE COMPORTE UNE PAROI LATERALE ANNULAIRE 41, UN FOND AJUSTE 42 ET UN COUVERCLE 43 MUNI D'ORIFICES DE TROP-PLEIN DE LIQUIDE 44. GRACE AU PROCEDE ON OBTIENT UN MATERIAU COMPOSITE PIEZO-ELECTRIQUE PARTICULIEREMENT AVANTAGEUX POUR LA REALISATION D'UN CAPTEUR PIEZO-ELECTRIQUE SENSIBLE AUX PRESSIONS HYDROSTATIQUES.