(K, Na) NbO3 based piezoceramics prepared by a two-step calcining and ball milling route

• A novel two-step calcining and ball milling route is proposed.
• The two-step route is based on solid state process of ceramic powder preparation.
• (K, Na) NbO3 based lead free piezoceramics is prepared through the two-step route.
• Fine and homogeneous powders were obtained by the two-step route.
• The electric properties of the bulk ceramics prepared by this route were enhanced.

A novel two-step calcining and balling route based on conventional solid state process was introduced to prepare the powder of Li, Sb, Ta co-doped (K, Na) NbO3 (KNN) ceramics. In the two-step route, a further step of calcining and ball milling was added to the conventional process. Powders in each step were characterized and the bulk ceramics were prepared to compare with the conventional one-step route. Fine and homogeneous powders were obtained and the solid state reaction was promoted after the two-step route. The electrical properties of the bulk ceramics were enhanced by the two-step route with piezoelectric constant d33 of about 292 pC/N form 252 pC/N, dielectric constant of 2060 from 1873. The results show that the two-step calcining and balling route is an effective way for powder preparation of KNN-based piezoceramics, especially in the future mass production case.