Vacuum sintered lunar regolith simulant: Pore-forming and thermal conductivity

Lunar regolith molding technologies are receiving an increasing attention in lunar exploration program. Most studies are carried out in the air on earth, ignored the effects of high vacuum (~?10^-12 mbar) on the lunar surface. This paper presents the results of a study aimed at assessing the effect of vacuum on the sintering of low Ti basalt type lunar simulant CLRS-1. The results show that porous sample with density of 1.19?g?cm^-3 can be obtained by sintering at 1100?°C under vacuum, which has much lower thermal conductivity (0.265?W?m^-1 K^-1) than concrete and other lunar resource derived structural materials. It could potentially be applied as the thermal insulation material for the Moon base construction. The pore-forming mechanism in vacuum was investigated. It was found that evaporation of the products of solid dissolved mineral crystals led to a great deal of weight loss and inhibited the densification during sintering.