Surface structures in micrometer scale were prepared on different substrates by a coating process using particle-filled slurries based on a blend of preceramic polymers. Parameters like solvent fraction, substrate material, filler particle size, and layer thickness were varied. Demixing reactions of solvent and polymers led to surface structures with pores of 1-60 mu m in diameter. The solubility parameters delta(t) of the polysiloxanes used are about 18.7 MPa1/2 for poly(methyl phenyl vinyl siloxane) and 19.5 MPa1/2 for poly(methyl siloxane), respectively. By pyrolysis of the green layers, ceramic coatings were obtained by keeping the particular surface structures.