Crystal structure and properties of Al2O3-Cr2O3 solid solutions with different Cr2O3 contents

To enable the comprehensive application of Al2O3-Cr2O3 solid solutions, the crystal structures and properties of Al2O3-Cr2O3 solid solutions with different Cr2O3 contents were studied. It was observed that Al2O3 and Cr2O3 form a complete substitutional solid solution over the entire composition range at 1650 °C, with no compounds being formed. Lattice parameters “a” and “c” both increase linearly with an increase in the Cr2O3 content. The doping of the Cr3+ ions causes a more severe lattice strain in the c-axis direction. The diffraction angles of the diffraction peaks decrease in a linear manner with the increase in the Cr2O3 content. The relationship between the theoretical density of the solid solution and the Cr2O3 content could be fitted using a second-order polynomial. It was also observed that the linear expansion coefficient of the solid solutions decreases with an increase in the Cr2O3 content.