Low-Firing Pb(Zr,Ti)O3-Based Multilayer Ceramic Actuators Using Ag Inner Electrode

We investigated the low firing of Li₂CO₃ added 0.2Pb(Mg1/3Nb2/3)O₃ - 0.3Pb( Fe1/2Nb1/2 ) - 0.5Pb(Zr0.475Ti0.525)O₃ (PMN-PFN-PZT) ceramics and multilayer actuators (MLAs) using Ag inner electrodes. It was found that 0.1 wt% Li₂CO₃ was quite effective in lowering the sintering temperature of PMN-PFN-PZT ceramics from 1,100∘C down to 900∘C without deteriorating their piezoelectric ceramics ( d₃₃ = 425 pC/N and kₚ = 61.9%). However, excess Li₂CO₃ up to 0.3 wt% brings about unwanted problems such as the formation of a LiPbO₂ secondary phase and subsequent degradation in the piezoelectric properties. Using 0.1 wt% Li₂CO₃ added PMN-PFN-PZT ceramics, MLAs with Ag inner electrodes were successfully fabricated, resulting in a normalized strain of 580 pm/V at an electric field of 1.5 kV/mm.