Effect of high concentration of an ideal donor dopant on the dielectric properties of potassium sodium niobate (KNN) lead-free piezoelectric ceramic

Barium Carbonate (BaCO3) was selected as dopant to examine its effect to the Potassium Sodium Niobate piezoelectric ceramic properties. In this work, the concentration of Barium was doped until highest stoichiometry disorder for stoichiometry ratio of K0.5Na0.5Nb3 (KNN). The mixed powder of KNN were calcined at 850 ˚C for 6 hours. Then the clean calcined powder was uniaxially-pressed about 200 MPa to produce green body pellet for 1 mm in thickness using Hydraulic Hand Press. The concentration of BaCO3 as dopant were ranged from 0.00 and 0.25 until 0.45. A green body pellet was conventionally sintered at 1120 °C for 2h in air atmosphere. A phase analysis was done using X-Ray Diffraction. Barium as dopant improve the density of KNN. The size of cubical grain in microstructure images were reduced with increasing Ba content indicate the phase transformation. The relative permittivity (467.74 to 26.85) and tangent loss (0.36726 to 0.24552) were reported decreasing trends at frequency of 1 kHz.