Synthesis of MgAl<sub>2</sub>O<sub>4</sub> Spinel in MgO–Al<sub>2</sub>O<sub>3</sub> and MgO–Al<sub>2</sub>O<sub>3</sub>–Al Systems via HPHT Sintering

The synthesis of magnesium–aluminum spinel (MgAl2O4) by high-pressure–high-temperature sintering within the MgO–Al2O3 and MgO–Al2O3–Al systems has been investigated. The experiments were carried out at a pressure of 2 GPa and temperatures ranging from 400 to 1600°C. Increasing the sintering temperature resulted in a higher MgAl2O4 content in both MgO–Al2O3 and MgO–Al2O3–Al systems. This, in turn, led to an increase in the hardness of the synthesized samples. The results suggest that high-pressure–high-temperature synthesis requires a sintering temperature of at least 1000°C in a pressure range of 2.0–5.0 GPa to achieve optimal physical properties.