GRAIN-GROWTH IN THE MNO ADDED ZNO-6 WT-PERCENT SB2O3 CERAMIC SYSTEM

The effect of MnO additions between 0 and 5 wt% to the grain growth of the ZnO-6 wt% Sb2O3 system was studied between 1000 and 1300 degrees C in air. The kinetic grain growth study carried out using the express ion G(n)-G(o)(n) = K-o.t.exp(-Q/RT) gave the grain exponent (n) value as 6 and the apparent activation energy (Q) for the grain growth proce ss as 630 kJ/mol. The MnO addition systematically lowered the grain gr owth exponent value from 6 to 4. The apparent activation energy for th e grain growth process with MnO additions up to 2 wt% was found to be 560 kJ/mol, which was lowered to 470 kJ/mol in MnO additions over 2 wt %. It was also observed that the twinned ZnO grains found in the Sb2O3 added system disappeared with the MnO additions. This indicated that the formation of fine spinel particles on the ZnO grains is the main s ource of the grain growth inhibition process in Sb2O3 added ZnO system s. Published by Elsevier Science Limited and Techna S.r.l.