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 degrees 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.