Silica-Aerogel Composites Opacified With La_0.7Sr_0.3MnO₃

As part of an effort to develop improved lightweight thermal-insulation tiles to withstand temperatures up to 1,000 °C, silica aerogel/fused-quartz- fiber composite materials containing La0.7Sr0.3MnO3 particles as opacifiers have been investigated as potentially offering thermal conductivities lower than those of the otherwise equivalent silica-aerogel composite materials not containing La0.7Sr0.3MnO3 particles. The basic idea of incorporating opacifying particles into silica-aerogels composite to reduce infrared radiative contributions to thermal conductivities at high temperatures is not new: it has been reported in a number of previous NASA Tech Briefs articles. What is new here is the selection of La0.7Sr0.3MnO3 particles as candidate opacifiers that, in comparison with some prior opacifiers (carbon black and metal nanoparticles), are more thermally stable.