Experimental procedures for CSP of

Experimental procedures for CSP of BaTiO3 using Ba(OH)2·8H2O flux are outlined in Fig. 1. 0.75 g of BaTiO3 and 0.15 g of Ba(OH)2·8H2O solid powders were homogeneously ground and mixed using a pestle and mortar prior to sintering. For each experiment, the mixture was loaded into a 12.7 mm diameter die and uniaxially pressed under 350 MPa. Since the melting point of Ba(OH)2·8H2O is 78 °C [27], a pre-heating step was conducted at 80 °C for 0.5 h to allow its homogeneous distribution in the BaTiO3 powder. Then, the set temperature was increased to 150 °C for CSP reaction, using both a heater jacket and a press equipped with hot plates and held for 1, 3, and 15 h. Samples were cooled down to room temperature.