Alumina ceramics doped with manganese titanate via applying Mn–Ti–O coatings to corundum micropowder

Abstract

The aim of this work was (i) to develop an untraditional method of alumina doping that ensures low sintering temperature and (ii) to obtain dense engineering ceramics with good mechanical properties by conventional sintering. A nanostructured coating of manganese–titanium oxides was applied to α-Al2O3 micropowder particles using liquid-phase synthesis of Mn–Ti–O–C–H xerogel and its annealing. The alumina modified in this way was sintered at 1300–1400 °C in air. The sintering process was accompanied by the formation of manganese metatitanate MnTiO3. The sintered samples have the relative density of about 97%, the bending strength of ≥ 260 MPa, and the Vickers microhardness of ≥ 16 GPa. The longitudinal and transverse sound velocities were measured, from which the Poisson’s ratio of 0.24 and the Young’s modulus of ≥ 360 GPa were calculated. Modification with MnTiO3 precursors yielded higher mechanical properties of ceramics than modification with a ready MnTiO3 coating. The results are compared with the properties of Al2O3 doped with Mn–Ti–O formulations in other studies, and of industrial alumina ceramics.