Papers by Keyword: Composition Gradation

Abstract: Functionally graded materials (FGM) based on stainless steel and ceramic materials have inspired researchers to combine properties and features which are not present in conventional composites, and are considered to be an alternative in the production of motors parts, cutting tools and coatings for reactors. The addition of metal and ceramic in a graded structure allows the integration of distinct properties that combine advantages of metallic and ceramic materials. Ceramic components withstand high temperatures and present high corrosion resistance, while metallic ones provide higher mechanical resistance, in particular ultimate tensile strength and fracture toughness. In this work, composites with variable levels of 316 Stainless Steel and Ytria-stabilized Zirconia, were prepared and characterized, in order to determine the thermal behavior of each composition, aiming the optimization of sintering of pieces with chemical composition gradation.

Abstract: Dense, uniform and crack-free mullite (3Al2O3·2SiO2) coatings were deposited on Sibased substrates by chemical vapor deposition using the AlCl3–SiCl4–H2–CO2 system. The coatings were compositionally graded, with the Al/Si ratio increasing towards the outer surface of the coatings for improved corrosion resistance. Mullite grains nucleated when the surface composition of the growing coating was in a narrow range close to that of stoichiometric mullite. The growth rate and crystal structure of mullite were dependent upon temperature, pressure, reactant concentration, and reactant ratios. The phase transformations occurring in these coatings during high-temperature anneals in the range 1100–1400 °C were studied.