Structure and electrical properties of textured Sr_(1.85)Ca_(0.15)NaNb_5O_(15) ceramics prepared by the reactive templated grain growth

摘要

Highly textured Sr_(1.85)Ca_(0.15)NaNb_5O_(15) (SCNN) ceramics with enhanced electrical properties were successfully prepared by the reactive templated grain growth method using acicular Sr_2KNb_5O_(15) (SKN) template particles. Through carefully controlling the processing conditions, a texture fraction of 0.88 was obtained when the ceramics were sintered at 1340℃ for 6 h. The obtained textured SCNN ceramics exhibited obvious anisotropic properties with the highest electrical properties shown in c-axis direction: ε_r=2270, ε_m =5902, T_c=247℃, tan δ=0.014, P_r=16.88 μC/cm~2 and d_(33) =162 pC/N. These properties were superior to those of randomly oriented SCNN ceramics with the same composition, showing that fabricating lead-free ceramics through reactive templated grain growth method is an effective way to achieve superior performance for commercial application. In addition, the formation mechanism of higher texture quality in SCNN ceramics was discussed in detail.