PYROLYSIS OF PB(ZR0.5TI0.5)O-3 PRECURSORS - AVOIDING LEAD PARTITIONING

Three different chemical precursor routes mere investigated to synthes ize Pb(Zr0.5Ti0.5)O-3: mixing hexanoates, acetate complexing of alkoxi des, and the synthesis of a mixed alkoxide by the reaction of titanium alkoxide and zirconium alkoxide with lead acetate, For each, elementa l Pb and PbO mere the first crystalline phase observed during pyrolysi s conditions that involved rapid heating (e.g., to 400 degrees C). The formation of Pb (and PbO) could be avoided by first heat-treating hyd rolyzed, mixed alkoxide precursor powders at 300 degrees C for 1 h. Th is treatment was not effective for the two other precursors. It is con cluded that both the carbonaceous content of the precursor (lowest for the hydrolyzed, mixed alkoxides) and the rate of hydrocarbon release during pyrolysis are critical to avoid the formation of elemental Pb d uring pyrolysis.