Sintering of wet-processed simulated Mars regolith slurries shaped using conventional and laser-induced slip casting (LIS)

In the framework of the future manned exploration of planet Mars, the availability of efficient manufacturing techniques for the in-situ exploitation of regolith represents a key target. In this regard, the newly developed Laser Induced Slip-Casting (LIS) technique is investigated in this work, starting from 100% in-situ available materials, as an additive manufacturing route. For the sake of comparison, traditional Slip-Casting (SC) was also employed.The use of clay-containing (2.5 wt%) materials and a Martian saltwater simulant as dispersion medium led to compact green bodies for both LIS and SC technologies. The obtained parts, after being characterized for their thermal stability both in oxidizing and inert conditions, have been sintered to produce dense specimens, with the best results observed operating at 1190 °C for 3h holding time in air, and 1180 °C for 3h in simulated Martian atmosphere. Compositional and magnetic analyses revealed different phase transformations occurring during the thermal treatments, i.e., Magnetite or Hematite formation, indicating that different phenomena occur in air and Martian atmosphere conditions. The modest compressive strength of the LIS-printed green bodies (about 0.9 MPa) can be significantly improved after sintering (about 100 MPa), obtaining values higher than most literature data. The LIS results are still inferior to the outstanding ones obtained in this work via the well-consolidated SC, underlining how promising the more advanced LIS technology, paired with oven sintering, could be in the ISRU framework.