Effect of B-site substitution by (Ni1/3Nb2/3)4+ for Ti4+ on microstructure and piezoelectric properties in (Bi1/2Na1/2)TiO3 piezoelectric ceramics

Abstract

To develop new (Bi 1/2 Na 1/2 )TiO 3 -based ceramics with optimum piezoelectric properties, lead-free piezoelectric ceramics of (Bi 1/2 Na 1/2 )Ti 1− x (Ni 1/3 Nb 2/3 ) x O 3 with x = 0, 0.01, 0.02, 0.03 and 0.04 have been synthesized by using a two-step calcination approach. The effect of B-site substitution by the complex (Ni 1/3 Nb 2/3 ) 4+ for Ti 4+ on microstructure and piezoelectric properties was investigated. X-ray diffraction analysis shows that the materials possess a pure perovskite structure. The grain size decreases and the diffuse phase transition behavior becomes more evident with increasing x . The piezoelectric constant d 33 increases and the planar electromechanical coupling factor k p exhibits no obvious enhancement with the increasing content of (Ni 1/3 Nb 2/3 ) 4+ substituting Ti 4+ in (Bi 1/2 Na 1/2 )TiO 3 ceramics. A maximum d 33 value of 101 pC/N is obtained at x = 0.03. The mechanism of piezoelectric properties changes was also discussed according to the domain-wall contributions to the piezoelectric response.