1) UFSC; (2) Uni-Bayreuth Coatings of a polysilazane-based ceramic/composite are a promising technology for the protection of steels for applications at higher temperatures (up to 1000ºC) and chemically harsh environments. The polymer to ceramic conversion process, from an adjusted pyrolysis treatment of the pre-ceramic polymer, allows to obtain uniform and homogeneous ceramics coatings with good adhesion to the surface of steels. In special, in the case of the stainless steel, direct chemical bonds are formed between the hydroxyl groups from the adsorbed water present at the passivate coating of the metal and the silicon chains of the polymer. However, associate with the polymer to ceramic conversion there is the shrinkage of the product which can be higher than 50% by volume. Invariably, the shrinkage results in the formation of residual porosity, cracks and defects, further an relatively low adhesion which can lead to delamination of the coating, especially under thermal cycling conditions. One efficient way of eliminate those effects is adding to the polymer an appropriate combination of passive and/or active fillers, which decreases significantly the volume change expected from the transformation. Besides, the utilization of passive/active fillers allows the adjustment of the thermal expansion coefficient and other properties of the coating, like special friction properties, electrical or thermal conductivity or catalytic activity. To this work, the polymer-ceramic transformation behavior of precursors and fillers, and their variables were evaluated, and the coatings on steel substrates were characterized. Long term tests were executed, with the objective of evaluating the quality of the coatings for applications at high temperatures and chemically aggressive environments which, currently, special and expensive grades of steel are used for. 20º CBECIMAT-Congresso Brasileiro de Engenharia e Ciência dos Materiais 04 a 08 de Novembro de 2012, Joinville, SC, Brasil