Th porosity gradient was formed in situ by sinhedntering layer-staccked green tapes withs
steepwise varied conntents of pore formmer.
Grraded porous piezzoceramics were fabricated by graadually increasing CB content, adjgjusting
the binder burnout procedure and tailoring the multettilayer thickness. In this way crack andks
dellaminations were avoided, leading to a well deveveloped and conntrolled microstrructure
with porosity rangi from 10 to 30 vol% (Fig. 6).ing
hestsN-FGM multilayer showed a mean acoustic impedanance ofTh preliminary tes done on PZTN
6 Kg/(m2s) an piezoelectric properties of S11E = 26 10-12 m/N, kp=0.38, d31 = -10 10-1215 10nd06
m/ Those data co/V.onfirmed the pottentiality of this material for ultramasonic devices an tapend
cassting as suitable ttechnique to prodduce porosity-graaded piezoelectric ceramics.c