Electrical Resistivity Measurement of the Molten Cordierite Glass Using Two-wire Method

Lead free potassium sodium niobate (KNN) piezoceramics were synthesized via conventional solid state sintering route. Tungsten oxide (WO_3) with nano and micron particles was used as a donor dopant. Dielectric and piezoelectric properties of samples sintered in the temperature range of 1110°-1145°C were measured by precision LCR-meter and APC d33-meter devices. SEM results revealed that micron WO_3 inhibited the grain growth of KNN ceramics and led to a finer microstructure. KNN with micron WO_3 had much finer microstructure and the sintering process terminated at higher temperature compared to pure KNN and KNN with nano WO_3. Nano and micron sized WO_3 affected the densification and electrical properties of KNN considerably. Additionally, KNN with nano WO_3 reached the maximum density at lower temperature compared to its counterpart. Finally, at 1125ºC KNN with 0.3 mol% nano sized WO_3 showed d_33, ε_r, tanδ, and Q_m of 75 pC/N, 345, 2%, and 50, respectively. For KNN sample with 0.3 mol% micron WO_3 at 1135ºC these values were 81 pC/N, 773, 3.3%, and 30, respectively.