Theoretical calculation and experimental verification of the vacuum thermal decomposition process of lunar silicon oxide

Thermal decomposition of oxides can be achieved at a lower temperature under vacuum condition. For In Situ Resource Utilization (ISRU), using the thermal decomposition method to obtain resources can avoid complex processing. This study, through thermodynamic equilibrium calculation found that oxides such as iron(II) oxide (FeO), and magnesium oxide (MgO), are easy to decompose. While oxides, such as silicon monoxide (SiO), titanium(II) oxide (TiO), etc., are difficult to decompose. Silicon dioxide (SiO2) is selected as the sample for the nanosecond laser experiment under a vacuum. Temperature simulation showed that a laser can give the sample high-temperature energy above 4700 K. Dynamic analysis showed that the sample undergoing complete plasma decomposition was the most thorough. The results of thermal decomposition of silicon monoxide is the most difficult to achieve. Under the conditions of 75 mJ laser pulse energy, 10−4 Pa initial vacuum, etc., the oxygen-silicon atom ratio of the products ranged from 1.74 to 0.12 and decreased with decreasing particle radius. Understanding the decomposition behavior of lunar surface oxides is crucial for the clean utilization of lunar surface resources. Moreover, it also provides a theoretical basis for high-temperature processing and element migration of airless objects. •Using pulsed laser as heat source, oxides can be decomposed directly without medium in vacuum.•The decomposition temperature and pressure range of oxide under vacuum are calculated by thermodynamics.•A model of pulse laser thermally induced instantaneous decomposition process and transfer phenomenon is proposed.•Nano-scale products are collected and characterized in situ and used standard samples for composition correction.