![]() At present, one topic of great interest about materials characterization is the relationship between the material structure and its properties, always seeking the correct operation of tool or devise. The study of mechanical, physical, chemical and structural properties are some of main characteristics for carry out the correct mechanical characterization of any material. The foregoing phenomenon implies to have a surface treatment combining the adaptability with low operative costs 5, 6, 7. The advantages of chemical vapor deposition technique by fluidized bed are in the combination of the thermal activation and fluidized bed, which has as result the increase of the heat and mass transfer among the fluidized bed, gas and samples, obtaining a great stability of the temperature and a homogenous mix of reactive gases and the fluidized particles generating a high quality reaction in the bed. The oxidation by water vapor has highly importance in materials selection for electric energy generation by vapor turbines, since in thermal plants many components are exposed to the water vapor at high temperature 4, 5, 6. However, the water vapor in the air or oxygen can have a not good effect in the stainless steels oxidation inducing it to the catastrophic oxidation, due to the formation of not-protective oxide layer rich in iron, reducing the performance and service life of iron. The ability of endure corrosion is attributed to the formation of dense oxide chromium layer formation and its slow growth. ![]() Therefore, to know the mechanical properties of protectives coatings has become an essential part to materials characterization, in order to develop in many way the substrate 1, 2, 3. The main objective of coatings is give extra properties to materials, which improve their chemical and mechanical characteristics, such as hardness, thermal protection, wear resistance and corrosion resistance, among others. The industry uses coatings to protect materials used in machinery construction and devises, extending their service life and reducing maintenance cost and production. The industrial growth has generated the research of alternative process, as well as new tools and materials, due to the market faces to changing requirements. Keywords: Chemical Vapor Deposition by Fluidized Bed (CVD - FBR), Coatings, Vapor oxidation, Corrosion, Hardness, Nanoindentation. ![]() Results of AFM verified a correlation between hardness and voltages profiles found during scanning. Cross-section samples were subjected to Atomic Force Microscopy (AFM) focusing on the thickness of coating (topographical changes, roughness gradient and possible formed phases). Additionally Scanning Electron Microscopy (SEM) was carried out to characterize micro-structural changes of the oxidized samples. Microhardness and nanoindentation studies were performed in order to assess the benefits of the Al-Si coating by CVD-FBR, finding an increase in the coating hardness with respect to the substrate. The coated samples were oxidized in water vapor loop at 750° C, which showed a decrease in the corrosion rate at high temperatures in respect with the oxidized uncoated substrate (more than 100 times). Palabras clave: Deposición química de vapor por lecho fluidizado (CVD - FBR), Recubrimiento, Oxidación en vapor de agua, Corrosión, Dureza, Nanoindentación.Īluminum-Silicon Al-Si coating deposited at 540° C on the austenitic stainless steel AISI 316 by chemical vapor deposition in fluidized bed reactor (FBR-CVD), afterwards samples were thermally treated at 750° C under argon for 2 hours. Los resultados AFM verificaron una correlación entre la dureza y los perfiles de voltaje encontrados durante los barridos. La sección transversal de las muestras fue sometida a Microscopía de Fuerza Atómica (AFM), enfocándose en el espesor del recubrimiento (cambios topográficos, gradiente de rugosidad y posibles fases formadas). ![]() Adicionalmente, Microscopía Electrónica de Barrido (SEM) fue llevada a cabo para caracterizar los cambios en la microestructura de las muestras oxidadas. Estudios de Microdureza y Nanoindentación fueron realizados con el fin de evaluar los beneficios del recubrimiento de Al-Si por CVD-FBR, encontrando un incremento en la dureza del recubrimiento con respecto al sustrato. Las muestras de estudio fueron oxidadas en un loop de vapor a 750° C, los cuales presentaron una disminución en la velocidad de corrosión a altas temperaturas con respecto a las muestras no recubiertas (más de 100 veces). El recubrimiento de Aluminio-Silicio fue depositado a 540° C sobre el acero austenítico AISI 316 por deposición química de vapor en lecho fluidizado (CVD-FBR), para luego ser tratado a 750° C en argón por 2 horas. ![]()
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