Sintering effect on electrical properties and morphology of lead-free Na0.92k0.08NbO3 ceramics

Abstract

Sodium potassium niobate (NKN) powders were synthesized by the solid-state reaction method. The NKN ceramics for composition Na0.92K0.08NbO3 (NKN) were then fabricated by a two-step sintering technique. The effects of the two-step sintering on the properties of the ceramics were investigated. The pure phase NKN was achieved for all sintering temperatures of 1100, 1150, 1200 and 1250?C. The observed change in the microstructure indicates that the grain size increases with the increasing sintering temperatures. Also, the two-step sintering technique produced a higher value of K/(K+Na) weight-% ratio and peak dielectric constant for sintering temperatures 1100, 1150 and 1200?C. However, further increasing of the sintering temperatures at 1250?C, reduces the K/(K+Na) weight-% ratio and the peak dielectric constant (?c).