Oxidation resistant Mo5SiB2 powders, which will be used as filler particles in polymer-derived ceramic (PDC) coatings, are processed by mechanical alloying and heat treatment. After microstructural analysis of the silicide particles they are incorporated in a preceramic polymer slurry. Subsequent pyrolysis results in a multi-phase composite consisting of a silicon oxynitride matrix and homogeneously distributed Mo silicide particles. Using cyclic oxidation tests it is shown that the newly developed particle-filled PDCs are promising for future application as protective oxidation barrier coatings on Mo-based materials. (C) 2019 Elsevier B.V. All rights reserved.