Effects of Ilmenite on the Properties of Microwave-Sintered Lunar Regolith Simulant

Microwave sintering is regarded as a high-efficiency, energy-saving, and rapid-heating technique for the preparation of structural materials on the Moon. However, the influencing factors (i.e., ilmenite content and sintering temperature) on microwave sintering processes are not well-understood. Herein, five lunar regolith simulants with different contents of ilmenite (i.e., 4.6%, 28.5%, 43.9%, 65.8%, and 80.9% by weight) were used for microwave sintering experiments at 1,050°C, 1,150°C, and 1,300°C. The characterization of the microstructure, mineralogy, thermal conductivity, and mechanical properties of the products shows that the ilmenite content and sintering temperature significantly affected the properties of the microwave-sintered products. The sintering product containing 4.6% by weight ilmenite at 1,300°C showed a dense texture, good thermal insulation properties (thermal conductivity of 0.15±0.005 W m−1 K−1), and optimal compressive strength (74.0±7.1 MPa). This suggests that adding ilmenite to lunar regolith does not improve the properties of microwave-sintered products. The results in this paper provide reference for the preparation of structural materials on the Moon in the future.