$Cr_2O_3$ doped $Pb(Zr_{0.525}Ti_{0.475})O_3$ piezoelectric ceramics were prepared from oxide mixture ($PbO,ZrO_2,TiO_2,Cr_2O_3$). Samples were sintered for 60min at 1250$^\circ{C}$ in alumina crucible containing the atmosphere powder ($PbZrO_3 + ZrO_2$) in order to keep a constant PbO partial pressure.
Dielectric and piezoelectric properties of specimens were measured for various compositions. Hysteresis loops and microstructure of each specimen were investigated. Aging rate of dielectric constant at constant temperature ($60\pm 2^\circ{C}$) was attained under various poling conditions.
It has been known that the domain wall motion was inhibited by $Cr_2O_3$ additions, but hysteresis loops showed that the effect of domain wall pinning of $Cr_2O_3$ was negligible at high electric field (larger than 10 kV/cm). This destabilizing field increased with $Cr_2O_3$ additions.
Aging rate decreased with $Cr_2O_3$ additions for every poling condition. In small additions (0-0.2 mol%), aging rate increased or microcracks were created with increasing poling field, because internal stress effect was predominant. In larger additions (0.4-0.6 mol%), aging rate decreased with increasing poling field, because the domain was stabilized during poling.
