Reaction Study of TC4 Alloy during <i>In-Situ</i> Extraction of Lunar Water

月球水原位探测是当今月球探测的热点，各国探测几乎都提出将钻取或表取月壤进行加热的方案来提取其中的水。TC4合金具有良好的材料性能被广泛应用于航天结构材料中，对含水量较低的月壤进行水探测，则要求其取样加热单元材料具有高度的稳定性。本文研究了TC4合金在200℃、400℃低压条件下与微量水蒸气短时间热氧化反应。本研究中发现TC4合金与在此研究实验条件下其氧化产物主要为纳米级的α-Al2O3，且通过后续的实验研究表明TC4合金在200℃低压条件下可用作含水量较低的月壤水探测材料。并且本文通过重复叠加氧化方法探索到TC4合金在400℃低压条件下α-Al2O3的厚度极限值，极大减少与外部含水氛围发生热氧化反应，从而更进一步提高该材料用于探测含水量较低的月壤中水的可行性。Lunar water in-situ detection has emerged as a focal point in contemporary lunar exploration, with most international missions proposing heating strategies (via drilling or surface sampling) to extract water from lunar regolith. TC4 alloy, renowned for its superior material properties, has been extensively utilized in aerospace structural applications. For water detection in low-moisture lunar regolith, the sampling and heating unit materials must exhibit exceptional stability. This study investigates the short-term thermal oxidation reactions between TC4 alloy and trace water vapor under low-pressure conditions at 200˚C and 400˚C. Our findings reveal that the primary oxidation product under these experimental conditions is nano-sized α-Al2O3. Subsequent experimental analyses demonstrate that TC4 alloy exhibits sufficient stability for low-moisture lunar regolith water detection at 200˚C under low-pressure environments. Furthermore, through a repeated superposition oxidation methodology, we have identified the thickness limit of α-Al2O3 formation on TC4 alloy at 400˚C under low-pressure conditions. This critical discovery significantly suppresses further thermal oxidation reactions with external water-bearing environments, thereby substantially enhancing the material’s feasibility for detecting trace water content in lunar regolith.