Abstract: In some examples, an article may include a substrate and a coating on the substrate. The substrate may include a superalloy, a ceramic, or a ceramic matrix composite. The coating may include a layer comprising a matrix material and a plurality of nanoparticles. The matrix material may include at least one of silica, zirconia, alumina, titania, or chromia, and the plurality of nanoparticles may include nanoparticles including at least one of yttria, zirconia, alumina, or chromia. In some examples, an average diameter of the nanoparticles is less than about 400 nm.