Low Temperature Sintering Of Alumina Ceramics Using Simple Slurry Casting Method

In this paper, alumina ceramics were successfully fabricated at a low sintering temperature assisted by MnO₂ - TiO₂ - MgO multiphase sintering additives using simple slurry casting method. The results showed that the multiphase sintering additive can effectively decrease the sintering temperature of the ceramics at a sintering temperature as low as 1350℃.The effect of the dispersant gum arabic on the flow ability of alumina slurry was studied. Results showed that was abtained and slurry viscosity lowered to 0.315 Pa·S, by adding 1 wt% of gum Arabic into the slurry with a PH value of 12. The slurry viscosity heavily related to its solid content alumina. The viscosity of slurry increased with the increasing alumina content, especially for 60 wt% solid content.The effect of adding different MgO (0.5wt%) and MnO₂ (3wt%) and fixed amount of TiO₂(1.0 to 3.0 wt%) on the properties of alumina at the same temperature was studied. Results showed that the additives can effectively reduce the alumina ceramic sintering temperature. Sintered density with increasing TiO₂ content from 3.72 g/cm³ to 3.80 g/cm³ at 1350℃. There was a big differedce in flexue strength sintered at 1350℃. The bending strength was the 243MPa for 1.5 wt% TiO₂ AT2 specimen comparing to that of the flexur shrength of 193MPa for 3.0 wt% TiO₂ AT2 samples and was 61MPa higher than that of AT2 specimen 1382MPa sintered at 1300℃. The strength value has reached the ordinary alumina ceramic flexural strength standardThrough analysis of different values of Rockwell hardness of sintered samples, it showed that a high value of 90.5 for the samples sintered of 1350℃was higher than the value of 83 for the samples sintered at 1300℃. Two set of samples brake down during the measurement due to this brittleness caused by high TiO₂ content.