Density and microstructure of TiO2-ZnO pellets sintered at below and above eutectic temperature

Varisator is generally produced from ZnO as base material. In order not to depend on one base material (especially ZnO) an in order to develop the varisator further, base material diversification is necessary. TiO2 is one of material that my be used as a varisator base material because it has electrical property similar to ZnO I.e. n-type semiconductor. Hypothetically, by adding ZnO into TiO and sintered the mixed oxides at temperature higher than the eutectic temperature (1418oC), a microstructure similar to ZnO based-varisator may be made. Based on that background, samples of TiO2 added with concentration of 0-9 mole % (TiO2 - ZnO) were sintered at 13000C and 1430oC for 2 hours. The sintered samples were analyzed methalographically using optical microscope and SEM, and analyzed using x-ray diffractometer. By considering form integrity of the pallets, it was now that the maximum concentration of ZnO could be added into TiO2 was about 2 mole %. Microstructure similar to that of ZnO-Bi2O3 varisator was found in TiO2- ZnO samples sintered at 14300C, however it was not found in those sintered at 13000C. X-ray diffraction analysis shown that TiO2-ZnO samples sintered either at 13000C or at 14300C had the same second phase I.e. Zn2TiO4, but the microstructure of them was different. Key words : microstructure, varisator, TiO2, ZnO, eutectic