The purpose of this work was to develop nickel self-lubricating composites using solid lubricant as second phase and obtained by powder metallurgy. The work involved the study of chemical stability and chemical interaction between the nickel alloy matrix and solid lubricating additives (molybdenum disulfide, graphite and hexagonal boron nitride). The results showed a thermodynamic stability during sintering for the composites containing the phases of graphite and hexagonal boron nitride. The presence of molybdenum disulfide phase permits a reaction with the matrix, the formation of a liquid phase of nickel sulfide and the solubilization of molybdenum in the matrix.

This work presents a study of TiO 2 thin films prepared by sputtering, for using as protection for biofouling action on marine structures. Titanium oxide thin films were prepared with different amount of oxygen on the surface of regular 1020 steel, a structural material for marine technology. The cristalline structure analysis evidenced the formation of anatase and rutile phases, as well as an amorphous phase of titanium oxide. Roughness measurements shown that the surface finish can contribute to the fixation of microorganisms. The crystalline TiO 2 thin films was evaluated as a potential biofouling protective coating. Contact angle measurements revealed that under UV-C light, the material evidenced a changing in wettability from hydrophobic to hydrophilic behavior, what is associated to the activation of photocatalytic reactions that is nocive for living beings on its surface. The effect of marine ambient on sample corroborates this conclusion, where after 6 months of exposure it was not sufficient for growing of biofouling on surface.

This work is concerned with issues related to using grey cast iron swarf from dry machining in powder metallurgy. In a first stage, a complete study on the characteristics of the raw powder is performed, in which aspects related to the dilution in different proportion of pure iron were studied. Low compacting pressure produces workpieces more resistant and that the ideal sintering temperature is 1160 °C. In a second stage, aiming at reduction of the powder, a heat treatment is performed. New dilutions using the decarburized powder were made and results showed better structural homogeneity and an improvement in the mechanical properties. The steel alloy 50/50% of swarf powder provided the best results. In a third stage, a cylindrical bearing was produced. New dilutions were made. Based on the control of the interconnected porosity, radial and wear resistance, the sample prepared with 100% swarf powder provided the best results.

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