Seamless joining of Al₂O₃ ceramic via lunar regolith for extraterrestrial applications

Inspired by in-situ resource utilization (ISRU), lunar regolith has emerged as a promising mediate for fabricating and repairing ceramic component on the Moon. Herein, we demonstrate the bonding of 95% Al₂O₃ ceramic using Apollo highland lunar regolith simulant as the interlayer, via an innovative ultrafast Joule shock joining (UJSJ) technique. The molten lunar regolith simulant exhibits excellent wetting behavior and compatibility with the Al₂O₃ substrates, enabling the formation of robust joints under pressure-free condition. Specifically, when a current of 65 A is applied with dwelling time of 22 s, a seamless joint is achieved, where bonding region processes an identical microstructure to the substrates. Shear fracture morphology reveals distinct intergranular separation mode for the seamless joint, which delivers a room temperature shear strength of 152 ± 7 MPa. More notably, the joint retains a shear strength of 72 ± 13 MPa even at 800 °C, showing its potential in high-temperature application.