The effect of titanium and zirconium oxides additives on thermal properties of magnesium aluminate spinel

Magnesium aluminate spinel (MgAl2O4) composites were prepared by mixing the commercial Alumina and Magnesium Oxide as starting raw materials. Titanium oxide (TiO2) and Zirconium oxide (ZrO2) were used as additives. The mixtures were prepared as by milling of five different combinations using zirconia balls for 1 hour each. Then Cold Isostatic Press (CIP) at 200 MPa pressed the batches. The material properties, such as porosity and density, and thermal expansion of the composites were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and the dilatometer measurements. MgAl2O4 ceramic composites are composed of spinel and garnet structures. The thermal expansion coefficients (CTE) of MgAl2O4 composites with and without TiO2 and ZrO2 additives under different temperature condition (25 degrees C to 1,300 degrees C) were characterized for spinel thermal expansion study and it shows that the comparison between the five different sample combinations at 1,300 degrees C, adding TiO2 or ZrO2 by small percentage gives the lowest CTE (9.89E-06, 1.02E-05) respectively, but increasing ZrO2 increases the CTE.