Aluminum precipitation on oxygen-deficient alumina in laser alumina reduction

Alumina reduction by thermal decomposition using CW laser ablation is being studied to obtain aluminum and oxygen on the lunar surface without the use of reducing agents such as carbon or hydrogen. When an alumina rod is heated by a laser beyond the ablation temperature, oxygen-deficient alumina (Al2O2.4-2.8) and aluminum microparticles are generated on the laser-irradiated surface. For this study, rods made of oxygen-deficient alumina were ablated to obtain more aluminum than normal alumina ablation. Results show that approximately 1.7 times as much aluminum was precipitated as that obtained from normal alumina ablation. The average particle size of the precipitated aluminum particles was found using SEM image analyses to be about 1.6 times larger than that of normal alumina.