[en] This study is divided in two parts. The first part is about the preparation of nanostructured Cr₃C₂-25(Ni20Cr) powders by high energy milling followed by characterization of the milled and the as received powder. Analyses of some of the data obtained were done using a theoretical approach. The second part of this study is about the preparation and characterization of coatings prepared with the nanostructured as well as the as received Cr₃C₂-25(Ni20Cr) powders. The high temperature erosion-oxidation (E-O) behavior of the coatings prepared with the two types of powders has been compared based on a technological approach. The average crystallite size of the Cr₃C₂-25(Ni20Cr) powder decreased rapidly from 145 nm to 50 nm in the initial stages of milling and thereafter decreased slowly to a steady state value of around 10 nm with further increase in milling time. This steady state corresponds to the beginning of a dynamic recovery process. The maximum lattice strain (ε = 1,17%) was observed in powders milled for 16 hours, and this powders critical crystallite size was 28 nm. In contrast, the lattice parameter attained a minimum for powders milled for 16 hours. Upon reaching the critical crystallite size, the dislocation density attained a steady state regime and all plastic deformation introduced in the material there after was in the form of events occurring at the grain boundaries, due mainly to grain boundary sliding. The deformation energy stored in the crystal lattice of the Cr₃C₂-25(Ni20Cr) powders milled for different times was determined from enthalpy variation measurements. These results indicated that the maximum enthalpy variation (δH = 722 mcal) also occurred for powders milled for 16 hours. In a similar manner, the maximum specific heat variation (δC_p = 0,278 cal/gK) occurred for powders milled for 16 hours. The following mechanical properties of Cr₃C₂-25(Ni20Cr) coatings prepared using the HVOF thermal spray process were determined: Vickers micro-hardness, the Young Modulus and the fracture toughness. The properties of the coatings prepared with the nanostructured and the 'as received' powders were compared. The hardness and Young Modulus of the coatings prepared with nanostructured powders were approximately 26% higher than that of the coatings prepared with 'as received' powders. The fracture toughness of the nanostructured coating was 36% higher. The erosion-oxidation resistance of the coating produced with the nanostructured powder was around 52% higher than that of the coating prepared with the 'as received' powders at 800 deg C. The E-O wastage of both types of coatings increased with temperature beyond 450 deg C. (author)