Impact of Porous Matrix Morphology on the Phase Diagrams in the GaInSn Alloy Under Nanoconfinement

Gallium alloys are widespread materials in microelectronics and are promising as components of nanocomposites for using in soft robotics, wearable electronics, and sensors. Here, we present NMR studies of the impact of a particular nanoconfinement on the phase diagram for the GaInSn eutectic alloy in a porous Al₂O₃ ceramic template with the middle pore size 11 nm. Measurements of the NMR spectra and Knight shifts were carried out for ⁷¹Ga, ⁶⁹Ga, and ¹¹⁵In isotopes from 180 to 310 K. The precipitation of gallium-rich segregates with crystalline structures of α- and β-Ga was found at cooling. The evolution of the NMR lines during cooling and warming evidenced the occurrence of the liquid–liquid-phase transition in the melt fraction with pronounced amount of indium. The results obtained for the GaInSn alloy embedded into the porous aluminum oxide ceramic were found to differ remarkably from the phase diagrams of the alloy confined within silica opal and glass porous matrices.