Effect of Manganese Addition on 94NBT-6BT Lead Free Multilayer Ceramics

Abstract

In this study, lead-free 94Bi0,5Na0,5TiO3-6BaTiO3 (94NBT-6BT) ceramics were fabricated by solidstate synthesis method at ambient atmosphere. Glassy phase and rounded particles in 94NBT-6BT was observed with increasing Mn content. The effects of doping manganese on the ferroelectric properties of 94NBT-6BT bulk ceramics were evaluated. From the XRD results of the calcined powders, peaks were slightly changed to higher 2 theta value while increasing manganese ratio. Multivalence additive Mn ions act as acceptor dopant in 94NBT-6BT structure at ambient atmosphere. Samples were sintered from 1075°C to 1175°C for 2 hours to obtain highest piezoelectric values. SEM results show that glassy phase and rounded particles in 94NBT-6BT was observed with increasing Mn content so, bulk density was enhanced up to 1125C. From the results, 0.3 wt% manganese doped 94NBT-6BT samples have highest electromechanical coupling factor about 0.23, mechanical coupling factor (Qm) 150 and d33 110 pC/N respectively. Further work, 94NBT-6BT and Mn-doped 94NBT-6BT multilayer actuators were manufactured by water-based tape casting technique. The active area was 49 mm 2 MLA and was fabricated by using Ag-Pd internal electrode without Pd-Bi reaction at the electrode-ceramic interface. Hysterisis loop measurements of manufactured lead free actuators were done by using Aixacct CMA module. Remnant polarization values of Mn-doped 94NBT-6BT MLA for a layer were higher than 6 µC/cm 2 .

Influence of Double Calcination-Milling Route on the Structural and Microstructural Properties of Lead-Free K0.5NA0.5NBO3 (Knn) Ceramics

“…The particle size distributions in Figure 2d shows a more uniform particle size distribution in double calcined sample where unimodal particle size distribution was observed unlike the single calcined sample. Particle size distributions have an important role in packing density which affects sintering [17]. Average particle sizes of single calcined and double calcined shows slightly different values which are 0.37 and 0.42 μm respectively.…”