As lead-free piezoelectric materials, Ag2O doped 0.95(K0.5Na0.5) NbO3-0.05LiNbO3+ x mol% (where x = 0, 0.5, 1, 1.5, 2, 2.5 and 3, respectively) ceramics were fabricated by a conventional sintering process. The doping effects on the microstructure and electrical properties of the 0.95(K0.5Na0.5) NbO3-0.05LiNbO3 ceramics were systematically investigated. When the 3 mol % Ag2O doped 0.95(K0.5Na0.5)NbO3-0.05LiNbO3 samples were sintered at 1,080℃ for 5 hrs in air, these ceramics showed excellent values of density=4.20 g/cm3, piezoelectric constant (d33)=174pC/N and phase transition temperature(Tc)=421.6℃, respectively.

Lead-free 0.98(Na0.5,K0.5)NbO3-0.02Li(Sb0.17Ti0.83)O3 (hereafter 0.98NKN-0.02LST) ceramics doped with Ag2O were prepared using a conventional mixed oxide method. The specimen showed superior structural and electrical properties when 1 mol% Ag2O was doped. For the 0.98NKN-0.02LST+1.0 mol%Ag2O ceramics sintered at 1,100℃, piezoelectric constant (d33) of sample showed the optimum values of 207 pC/N. The 0.98NKN-0.02LST+1.0 mol%Ag2O ceramics are a promising candidate for lead-free piezoelectric materials.