Microstructure and mechanical properties of MgO-doped Al₂TiO₅ prepared by reactive sintering

抄録

MgO-doped Al₂TiO₅ ceramics were reactively sintered from commercial α-Al₂O₃, TiO₂ anatase and MgCO₃ (basic) powders. Powder mixtures with molar ratio of Al₂O₃:TiO₂:MgO = 1:1:0, 1:0.95:0.05, 1:0.90:0.10, and 1:0.85:0.15 were prepared by wet ball-milling with ZrO₂ media. The green pellets were sintered at 1300–1500°C for 2 h in air to obtain dense samples. With changing the MgO doping amount, Al₂TiO₅/Al₂O₃, Al₂TiO₅/MgAl₂O₄/Al₂O₃, Al₂TiO₅/MgAl₂O₄ composites were synthesized. MgO doping was effective to reduce the Al₂TiO₅ matrix grain size and to reduce the strong anisotropy of Al₂TiO₅, which resulted in fewer microcracks. The maximum strength of samples sintered at 1400 and 1500°C were 106 and 32 MPa (15 mol % MgO), respectively.