Role of BiScO3 in phase structure and electrical properties of potassium sodium niobate ternary materials

Abstract

Abstract In this work, we mainly studied the effects of BiScO 3 contents on the phase structure and electrical properties of lead-free (K,Na)NbO 3 -based ternary ceramics, and the material system of (0.97- x )K 0.40 Na 0.60 NbO 3 - x BiScO 3 -0.03Bi 0.5 (Na 0.6 K 0.3 Li 0.1 ) 0.5 HfO 3 was prepared by the normal sintering method. The rhombohedral-tetragonal (R-T) phase boundary could be tuned in the ceramics by controlling BiScO 3 contents. When the compositions approach the R-T phase boundary, the ceramics possess the enhancement of dielectric, ferroelectric and piezoelectric properties. The ceramics with x \u202f=\u202f1.2% exhibited an excellent electrical behavior of d 33 \u202f=\u202f362\u202fpC/N, k p ∼0.42, P r ∼19.9\u202fμC/cm 2 , e r ∼1671, and tan δ ∼0.02, which is assigned to the involvement of R-T phase boundary. Moreover, a high Curie temperature ( T C ) of ∼315\u202f°C can be maintained even if the BiScO 3 contents increase because of the addition of both BiScO 3 and Li. As a result, the ceramics with x \u202f=\u202f1.2% had both a large d 33 and a high T C , showing that such a lead-free piezoelectric ternary system is suitable to the high-temperature applications.