Lead zirconate titanate via reaction sintering of hydroxide precursors

Abstract

Lead zirconate titanate (PZT) has been successfully fabricated via a unique one-step sintering processing route, which is simpler than the traditional precursor-calcination-milling-pelleting-sintering route and is able to deliver an enhanced sintered density at a much reduced sintering temperature. The hydroxide precursor was prepared by coprecipitation from a mixed nitrate solution containing Pb2+, Zr4+, and Ti4+ ions, and it was then compacted into pellets without being calcined at a low temperature. The precursor pellets were dehydrated at 400, 500, and 600°C for 4 h, respectively, followed by an isostatic pressing at 350 MPa, prior to being sintered at a high temperature. Dehydration temperature has a large impact on the sintering behavior of these hydroxide-derived PZT ceramics. The PZT dehydrated at 400°C was seriously cracked when sintered at temperatures ranging from 950 to 1150°C, due to the incomplete dehydration. A sintered density of 99.2% theoretical density was obtained at 1050°C for 2 h for the powder pellet dehydrated at 500°C for 4 h. It exhibits a dielectric constant of 1024 and a dielectric loss of 2.1% at a frequency of 1 kHz at room temperature. A calcination at a too-high temperature, e.g., 600°C, results in a reduction in the sinterability of the precipitate-derived PZT ceramic.