OLANDIR VERCINO CORREA
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Artigo IPEN-doc 25743 Corrosion characterization of AISI 304 stainless steel filter2018 - BARBOSA, L.P.; CORREA, O.V.; KARSOKAS FILHO, N.; COSTA, I.Pre-sintering for removal of lubricants is one of the most important steps in processing of powder metallurgy materials to achieve corrosion resistance. This is often the most neglected step in the sintering process. Incomplete removal of these organic compounds may result in sensitization of sintered parts. The aim of this study is to investigate the effect of lubricant removal process on the corrosion resistance of sintered AISI 304 L stainless steel filters. Pre-sintering was carried out at 450° C and sintering at 1150° C. As lubricant, 1% wax was used. The corrosion resistance of sintered samples was evaluated by polarization and tests, optical and scanning electron microscopy. The results showed that lubricant removal was not complete and during sintering sensitization of the stainless steel occurred decreasing the localized corrosion resistance of the stainless steel.Artigo IPEN-doc 25056 Study of the correlation between microstructure and corrosion resistance of the AZ91D magnesium alloy2018 - ANTUNES, RENATO A.; OLIVEIRA, MARA C.L. de; FERRAZ, LUCAS C. de C.; GONCALES, LETICIA dos R.; CORREA, OLANDIR V.The aim of the present work was to study the influence of beta phase precipitates content and distribution on the corrosion behavior of the AZ91D magnesium alloy, using samples subjected to solution annealing and aging. The morphology of the beta phase was observed using optical microscopy and scanning electron microscopy. The volume fraction of each phase was also determined. Potentiodynamic polarization tests and immersion tests were carried out, indicating an increase of the corrosion resistance with the volume fraction of the beta phase and its distribution on the grain boundaries of the alpha-phase. Solution annealed samples were more susceptible to corrosion.Artigo IPEN-doc 22561 High temperature erosion-oxidation behavior of thermally sprayed NiCr based alloy and cermets coatings2006 - KUNIOSHI, C.T.; CORREA, O.V.; RAMANATHAN, L.V.Artigo IPEN-doc 09697 Influence of processing parameters on the microstructure and oxidation behavior of hot pressed Ni-20Cr + WC metal matrix composites2003 - KUNIOSHI, C.T.; CORREA, O.V.; BELLINATI, C.E.; RAMANATHAN, L.V.Ni20Cr+WC composites with a gradient in the volume fraction of hard WC particles are ideal materials for applications where high temperature oxidation and erosion resistance are desired properties. The WC particles impart erosion resistant and the Cr content of the alloy, oxidation resistance. This paper presents the influence of WC particle content and consequently the extent of densification, on the oxidation behavior of hot pressed Ni20Cr+WC composites. Oxidation measurements in the range 700-1000°C revealed overall parabolic behavior. The increase in oxidation rate with WC content has been attributed to formation of islands of WO3 globules protruding through the Cr2O3.Artigo IPEN-doc 09707 Corrosion resistance of powder injection moulded AISI 316L and 17-4PH stainless steels in acid rain environments2003 - SOBRAL, A.V.C.; FRANCO, C.V.; CORREA, O.V.; COSTA, I.Artigo IPEN-doc 10935 Corrosion and cytotoxicity evaluation of AISI 316L stainless steel produced by powder injection molding (PIM) technology2005 - COSTA, I.; ROGERO, S.O.; CORREA, O.V.; KUNIOSHI, C.T.; SAIKI, M.This study investigates the in vitro corrosion and cytotoxicity response of AISI 316L stainless steel produced by powder injection molding (PIM) technology in a solution that simulates physiological fluids (MEM) by electrochemical techniques and neutral red uptake cytotoxicity assay. The results were compared with those of AISI 316L produced by conventional metallurgy. Both steels showed high corrosion resistance and no toxic effect in the cytotoxicity test. The corrosion products were analyzed by instrumental neutron activation analysis (INAA). The surfaces of the alloys were evaluated before and after corrosion test by scanning electron microscopy and a passive behaviour was indicated supporting the results from other techniques.Artigo IPEN-doc 13121 Effect of high energy milling parameters on nanostructured Cr3C2-Ni20Cr powder characteristics2008 - CUNHA, C.A.; PADIAL, A.G.F.; LIMA, N.B. de; MARTINELLI, J.R.; CORREA, O.V.; RAMANATHAN, L.V.Cr3C2-NiCr coatings have been used for corrosion and wear resistant applications. In the last decade, thermal sprayed coatings using nanostructured feed stock of other materials has exhibited higher hardness, strength and corrosion resistance. Hence, it is anticipated that nanostructured Cr3C2-NiCr coatings will also exhibit these properties and therefore posses improved performance characteristics. Preparation of nanostructured feed stock powders is the first step in the synthesis of nanostructured coatings and mechanical milling is an effective process to obtain the powders. Preliminary studies in which commercial Cr 3C2-NiCr powders were milled in hexane and gaseous nitrogen revealed that particle and crystallite size were significantly smaller in powders milled in nitrogen. This paper presents the effect of hexane content and milling parameters on Cr3C2-Ni20Cr powder characteristics. Use of just sufficient hexane as the milling media reduced significantly the particle and crystallite sizes.Artigo IPEN-doc 15941 TiG welding of sintered AISI 316 L stainless steel2010 - NEVES, MAURICIO D.M. das; BARBOSA, LUZINETE P.; SILVA, LUIS C.E. da; CORREA, OLANDIR V.; COSTA, ISOLDAArtigo IPEN-doc 16523 Effect of Crsub(3)Csub(2)-NiCr powder characteristics on structure and properties of thermal sprayed nanostructured coatings2010 - PADIAL, A.; CUNHA, C.A.; CORREA, O.V.; LIMA, N.B. de; RAMANATHAN, L.V.