Flexible and robust YAG-Al2O3 composite nanofibrous membranes enabled by a hybrid nanocrystalline-amorphous structure

A flexible and robust YAG-Al2O3 composite nanofibrous membrane was fabricated by a combination of sol-gel and electrospinning methods, then a sintering at 900 °C. The effects of Al2O3 on the microstructure and mechanical performance of YAG nanofibrous membranes were investigated. The YAG nanofibrous membrane is brittle but the composite membranes exhibit a brittle-to-flexible transformation as the Al2O3 content reaches 30 wt.%, which can be attributed to an optimized dense hybrid microstructure consisting of finer YAG grain size surrounded by amorphous Al2O3. The YAG-30 wt.% Al2O3 nanofibrous membrane sintered at 900 °C shows a tensile strength of 3.52±0.31 MPa, three times of that of pure Al2O3 sintered at the same temperature. The membrane still presents a decent flexibility with a tensile strength of 0.75±0.25 MPa after sintering at 1000 °C, which is at least 100 °C higher than the sintering temperature of most reported ceramic nanofibrous membranes.