Grain growth in TiO2-added ZnO–Bi2O3–CoO–MnO ceramics prepared by chemical processing

Abstract The effect of TiO 2 on the grain growth of the ZnO–Bi 2 O 3 –CoO–MnO ceramic system prepared by chemical coprecipitation, was studied between 1150 and 1300 °C in air. Bi 2 O 3 melts during firing, and then TiO 2 dissolves into Bi 2 O 3 -rich liquid. TiO 2 initially reacts with Bi 2 O 3 to form Bi 4 Ti 3 O 12 . Above ≈1050 °C, Bi 4 Ti 3 O 12 reacts with ZnO to form Zn 2 TiO 4 spinel phase. The kinetic study of grain growth carried out using the expression G n –G o n =K o ·t· exp (− Q RT) gave grain exponent ( n ) value as 6 and the apparent activation energy ( Q ) as 226.46 kJ/mol. 1.00 mol% TiO 2 addition increased the grain growth exponent value from 6 to 7 and apparent activation energy with 1.00 mol% TiO 2 addition was found to be 197.10 kJ/mol. The ZnO grain size gradually increases with increasing TiO 2 content. Addition of TiO 2 may increase the reactivity of the Bi 2 O 3 -rich liquid towards the ZnO grain, thus affecting the ZnO grain growth.