Thin films of RuO2 are attracting considerable interest lately, because of their various applications as advanced materials in the chemical and electronics industries. In this work, a coating technique has been developed that results in the formation of homogenous RuO2 coatings on stainless steel substrates. Metallic Ru is first vaporized using ozone (O-3) to form a gaseous mixture of RuO4, air and ozone. Then, the RuO4 is reduced and deposited as a thin RuO2 film on a hot (400 degrees C) stainless steel substrate. The coating produced has a needle-like structure, which leads to a significant increase in the surface area of the RuO2 coating. The stainless steel substrate tends to oxidize under the experimental conditions employed with the formation of a CrOx surface layer. As a result of the presence of this CrOx layer, the RuO2 films have good adhesion to the substrate. (c) 2006 Elsevier B.V. All rights reserved.