ADONIS MARCELO SALIBA SILVA

ADONIS MARCELO SALIBA SILVA

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Sintered Nickel Casing for Irradiation Targets
2016 - MIYANO, R.S.L.; TAKIISHI, H.; SOARES, E.P.; SALIBA-SILVA, A.M.; ROSSI, J.L.
The aim of this work was to develop an alternative way to obtain casings used with irradiation targets containing uranium, for the production of the radionuclide Mo-99-Tc99m. The targets used for the production of Mo-99 are materials containing U-235 designed to be irradiated in a nuclear reactor. Usually these targets are encapsulated in aluminum or stainless steel. The idea here is to obtain casings by encapsulating a uranium button or a metallic cylinder with compacted and sintered nickel powder, this serving as a sealing for the fissile products occurring during U-235 irradiation. The sintered high purity nickel powder samples were compacted in uniaxial hydraulic press at 195 MPa. The sintering of the samples was carried out in an open-air furnace in an atmosphere with a certain control using titanium-machining chips at 600 ˚C. The samples bulk density was evaluated by the Archimedes' principle. The porosity of 20.08% was measured by mercury porosimetry. The microstructure was investigated by scanning microscopy revealing interconnected porosity and nickel oxide at the particles boundary surface. The results obtained by sintering of nickel powder according to the experimental undertaken, indicate the feasibility of achieving a casing for uranium targets.
A comparative study of the corrosion resistance of stainless steels obtained by powder metallurgy techniques for application in dental prosthesis
2010 - MARQUES, R.A.; SALIBA SILVA, A.M.; ROGERO, S.O.; MONTEMOR, M.F.; COSTA, I.
Ferromagnetic stainless steels (SS) produced by powder metallurgy (PM) techniques have been investigated as potential candidates for dental prosthesis applications in replacement of magnetic attachments made of noble and expensive alloys. Two SS were investigated: SS 17-4 PH produced by powder injection (PIM) and SS PM2000 obtained by mechanical alloying. In vitro cytotoxicity analysis of the two SS showed no cytotoxic effects. The magnetic retention force of both tested SS was also evaluated and they were comparable to noble commercially available material that is in use at the moment. The corrosion resistance of both SS was evaluated by electrochemical techniques in sodium phosphate buffer solution (PBS) at 37°C. The AISI 316L SS was also tested under the same conditions for comparison reasons. SS samples tested showed passive behaviour in the electrolyte, but they also presented susceptibility to pitting. The best pitting resistance was associated to the PM2000 whereas the 17-4PH PIM showed the highest pitting susceptibility among the tested steels. The results pointed out that the PM2000 SS might be considered a potential candidate for substitution of high cost magnetic alloys used in dental prosthesis.
Characterization of sintered NdFeB magnets after phosphating in alkaline and acid environments
2003 - SALIBA SILVA, A.M.; MELO, H.G.; BAKER, M.A.; BROWN, A.M.; COSTA, I.
Fabrication of U3Si2 powder for fuels used in IEA-R1 nuclear research reactor
2008 - SALIBA SILVA, A.M.; DURAZZO, M.; CARVALHO, E.F.U.; RIELLA, H.G.
Powdered uranium silicide (U3Si2) 20% U235 enriched is an intermetallic compound used as nuclear fuel material dispersed in aluminum to be the meat of fuel elements. U3Si2 powder is the state-of-the-art as nuclear fuel material mostly used in modern research reactors. Its recent established fabrication in IPEN replaced the previous ceramic powder U3O8 used in the fuel of IEA- R1 (IPEN/CNEN, São Paulo, Brazil). The U3Si2 is a compound with 92.3%wtU and 7.7%wtSi. Its production is made by induction furnace melting using metallic uranium, produced by magnesiothermic reaction, and pure silicon. The induction furnace melts under argon controlled environment using zirconia crucible. Homogenization of liquid bath at 1800°C is a compromise between crucible resistance and homogenized melting, avoiding hazardous happenings. IPEN produced its first lot of enriched U3Si2 in September 2004, with a continuous fabrication ever since. This research work represents the ability of having fully Brazilian supply of this strategic and high cost nuclear material. The fuel quality meets the world quality standards required by International Atomic Energy Agency (IAEA) and RERTR standards. Brazilian production of U3Si2 powder not only closed the fuel cycle, from uranium mineral to fuel element, but also allowed higher productivity of nuclear medicine radioisotopes by IEA-R1.
Thermal interdiffusion products of U-10Mo in Al matrix
2010 - MARTINS, ILSON C.; SORIANO, GUILHERME Z.; DURAZZO, MICHELANGELO; CARVALHO, ELITA F.U. de; MONTAGNA, LEA S.; SALIBA SILVA, ADONIS M.
Nickel electrodeposition over powder compact for irradiation target
2012 - SALIBA-SILVA, A.M.; GARCIA, R.H.L.; MARTINS, I.C.; URANO de CARVALHO, E.F.; DURAZZO, M.