CECÍLIO ALVARES DA CUNHA
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Artigo IPEN-doc 23482 High temperature erosion-oxidation resistance of thermally sprayed nanostructured Cr3C2-25(Ni-20Cr) coatings2017 - CUNHA, CECILIO A. da; CORREA, OLANDIR V.; SAYEG, ISAAC J.; RAMANATHAN, LALGUDI V.This study reports the high temperature erosion-oxidation (E-O) behavior of conventional and nanostructured Cr3C2-25(Ni-20Cr) coatings prepared by high velocity oxygen fuel (HVOF) spraying. As-received and nanostructured Cr3C2-25(Ni-20Cr) powders with mean crystallite sizes of 145 nm and 50 nm respectively, were used to prepare 120 - 200 μm thick coatings on AISI 310 samples. The E-O behavior of the coatings prepared with the as-received (AR) and nanostructured (NS) powders was determined as weight change in a custom designed rig at room temperature, 450, 700 and 800 ºC. The Vickers microhardness, Young’s Modulus and fracture toughness of the AR and NS coatings were determined, and the NS coatings exhibited higher values compared with the AR coatings. The E-O resistance of the NS coating was higher than that of AR coating at all temperatures, and particularly at 800 ºC. The increase in E-O resistance of the NS coatings is due to its superior mechanical properties as well as to the presence of some heterogeneities in the AR coatings. The E-O mechanisms of both types of the coatings are discussed, with special attention to that at high temperatures. The results suggest that at 800 ºC the E-O process is controlled by erosion of the oxide.Resumo IPEN-doc 13320 Structure and properties of thermal sprayed nanostructured Cr3C2-25(Ni20Cr coatings2008 - PADIAL, A.; CUNHA, C.A.; BRESSIANI, A.H.; RAMANATHAN, L.V.Artigo IPEN-doc 15882 Thermal stability and erosin-oxidation behaviour of nanostructured Crsub(3)Csub(2)-Ni20Cr coatings2010 - PADIAL, A.; CUNHA, C.A.; CORREA, O.V.; RAMANATHAN, L.V.Artigo IPEN-doc 18563 Mechanical properties and erosion-oxidation resistance of thermally sprayed nanostructured Crsub(3)Csub(2)-25(Ni-20Cr) coatings2012 - CUNHA, C.A.; CORREA, O.V.; SAYEG, I.J.; LIMA, N.B. de; RAMANATHAN, L.V.Artigo IPEN-doc 18559 Structural and thermodynamic properties of Crsub(3)Csub(2)-25(Ni20Cr) powders produced by high energy milling2012 - CUNHA, C.A.; CORREA, O.V.; SAYEG, I.J.; LIMA, N.B. de; RAMANATHAN, L.V.Artigo IPEN-doc 18564 Mechanical and structural properties of thermal sprayed Crsub(3)Crsub(2)-25(Ni20Cr) nanocomposite coatings2012 - CUNHA, CECILIO A. da; CORREA, OLANDIR V.; SAYEG, ISSAC J.; LIMA, NELSON B. de; RAMANATHAN, LALGUDI V.Artigo IPEN-doc 14778 Structure and properties of thermal sprayed nanostructured Crsub(3)Csub(2)-25(Ni20Cr) coatings2009 - PADIAL, A.; CUNHA, C.A.; LIMA, N.B.; MARTINELLI, J.R.; CORREA, O.V.; RAMANATHAN, L.V.Artigo IPEN-doc 16983 Mechanical and thermodynamic properties of Crsub(3)Csub(2)-25(Ni20Cr) composite powders produced by high energy milling2011 - CUNHA, C.A.; CORREA, O.V.; SAYEG, I.J.; LIMA, N.B. de; RAMANATHAN, L.V.Artigo IPEN-doc 13124 Microstructure and mechanical properties of thermal sprayed nanostructured Cr3C2-Ni20Cr coatings2008 - CUNHA, CECILIO A. da; LIMA, NELSON B. de; MARTINELLI, JOSE R.; BRESSIANI, ANA H.A.; PADIAL, ARMANDO G.F.; RAMANATHAN, LALGUDI V.Cr3C2-Ni20Cr coatings have been used for corrosion and wear resistant applications. However, one of the shortcomings of these coatings is its low hardness, and consequent low wear resistance, for long term high temperature applications. Nanostructured coatings of many materials have exhibited higher hardness and strength compared with conventional coatings of the same material. Consequently, nanostructured coatings of other materials, including Cr3C2-Ni20Cr have been attempted to enhance overall performance. In this study the effects of high energy milling parameters on Cr3C2- 25(Ni20Cr) powder characteristics as well as the microstructure and mechanical properties of nanostructured Cr3C2-25 (Ni20Cr) coatings formed by high velocity oxygen fuel (HVOF) spraying have been evaluated. The average particle size and crystallite size of milled Cr3C2-25 (Ni20Cr) powders decreased with increase in milling time and this decrease was more pronounced in nitrogen compared to that in hexane. This difference has been attributed to a cushioning effect in the latter medium. The coatings prepared with milled Cr3C2-25 (Ni20Cr) powders had a more uniform microstructure, were harder and had higher relative fracture toughness compared with coatings prepared with as-received powders.Artigo 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.