Polysilazane-based coatings were prepared on dense and porous substrates by dip-coating. Both the pure, liquid polymer and polymer solutions in cyclohexane were investigated. Relevant properties of the coating solutions, including rheological properties and surface tension, were determined and used to predict the resulting layer thickness as a function of dip-coating parameters on dense borosilicate glass substrates. A good correlation between existing model (Landau and Levich) and experiment

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... s found for the pure polymer. In the presence of a solvent, evaporation phenomena led to a predicted coating thickness that is much less than the experimental value for all dip coating withdrawal spends. The introduction of a correction factor was found to adequately describe the deviation. In case of porous substrates, the coating thickness could not be predicted using the model due to infiltration of the base structure, resulting in an interpenetrating ceramic composite layer after pyrolytic conversion of the preceramic polymer compound. When preparing polymer-derived ceramic films on porous base materials, e.g. for membrane applications, this phenomenon has to be taken into account.