New lead zirconate titanate-based piezoceramic material

摘要

Lead zirconate titanate-based compounds of formula (I) or (II) are new piezoelectric ceramic materials. A new piezoelectric ceramic material is based on a lead zirconate titanate of formula (I) or (II). (1-u)Pb(ZrxTi1-x)O3-u'A<2+>(B'0.251+B0.755+)O3(+wMe25+O5) (I) and (1-u-v)Pb(ZrxTi1-x)O3-uA1+B5+O3-v(Sr1-yBay)2Nb2O7 (II): A1+ = alkali metal (preferably Na and/or K) ion; A2+ = alkaline earth metal (preferably Sr and/or Ba) ion; B' = alkali metal (preferably Na and/or K) ion; B, Me and B5+ = pentavalent metal selected from Ta, Sb and preferably Nb; x = 0.40 to 0.55; u' = 0 to 0.10; y= 0 to 1.0; u, v =0 to 0.05; and w = 0 to 1 wt.%. An Independent claim is also included for production of the above piezoelectric ceramic material by: (a) incorporating, as a ternary or quaternary solid solution in lead zirconate titanate, the corresponding lead-free perovskite of formula A1+B5+O3 or A2+B'0.251+B0.755+O3 optionally in combination with the corresponding alkaline earth metal niobate of pyrochlor type, the raw materials being metal oxides or carbonates; (b) processing by the mixed oxide route; and (c) densely sintering the resulting green body at below 1150 deg C.