$Pb(Zr_{0.525}Ti_{0.475})O_3$ piezoelectric ceramics, both unmodified and doped with NiO, were prepared by the conventional oxide techniques, using sintering temperatures from 900 to 1280℃. The experimental results showed that the sintering temperature producing the optimum densification is altered by the oxide additions. The difference in densification process between unmodified and NiO doped PZT ceramics was studied by shrinkage vs. firing temperatures and it was caused by increasing defect concentration in calcining process of NiO doped PZT ceramics.
In addition to this difference, weight changes before and after sintering were measured in order to establish the defect formation model. Oxygen vacancies produced by B site substituted Ni ions promote densification of NiO doped PZT ceramics at final stage of sintering, and NiO addition causes the inhibition of grain growth. And Nickel oxide solubility limit for $Pb(Zr_{0.525}Ti_{0.475})O_3$ ceramics is shown to be at the range from 0.2wt% to 0.5wt% from this defect model and other experiments. And then dielectric and piezoelectric properties of NiO doped PZT ceramics were measured for various compositions.
The purpose of this study was to investigate the effect of calcining on densification of NiO doped PZT ceramics and defect formation model for B site substituted dopants in PZT ceramics and piezoelectric properties of NiO doped PZT ceramics.
