ROGERIO ALBUQUERQUE MARQUES

ROGERIO ALBUQUERQUE MARQUES

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The comparison of the corrosion resistance of advanced ferritic stainless steels by Mott-Schottky approach
2009 - MARQUES, R.A.; TERADA, M.; SALIBA-SILVA, A.M.; PADILHA, A.F.; COSTA, I.
Ferromagnetic stainless steels (SS) have been investigated as potential candidates for dental prosthesis applications in replacement of magnetic attachments made of noble and expensive alloys. In order to be used as biomaterials, their corrosion resistance has to be appropriate. The corrosion resistance of passive materials is related to the characteristics of the passive film formed and this property might be investigated by Mott-Schottky procedure. The capacitance of passive films formed during 2 days of immersion in a Phosphate Buffered Solution (PBS), at room temperature on PM2000, DIN 1.4575 and 17-4 PH ferritic stainless steels (SS) was studied by Mott-Schottky approach. A commercial alloy was also analyzed for comparison reasons. The results showed that films on tested materials behave as both, n-type and p-type semiconductors and the PM2000 presented the highest corrosion resistance among all materials studied.
Corrosion investigation of a ferritic stainless steel for use as implantable dental devices with magnetic connections
2016 - COSTA, I.; ROGERO, S.; TERADA, M.; MARQUES, R.A.; BARBOSA, L.P.
Ferritic stainless steels might be used for applications as biomaterials when their magnetic properties are useful for fixing prostheses by means of magnetic attachments. The AISI 444 stainless steel (SS) is a non-cytotoxic ferromagnetic stainless steel but its application as biomaterial has not been extensively investigated. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and with the addition of Ti and Nb as stabilizers, were investigated to evaluate its potentiality for biomaterials fabrication.The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C, naturally aerated. The results were compared to that of the ISO 5832 SS. This last steel is the most used metallic material for orthopedic prostheses fabrication. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. In aerated condition, the resistance to pitting corrosion associated to AISI 444 SS was similar to that of the ISO 5832 SS. The AISI 444 stainless steel showed a high potential for use as a biomaterial, especially for the manufacture of prosthetic components with magnetic attachment.
Corrosion resistance and cytotoxicity evaluation of ferromagnetic materials for use in dental prosthesis
2016 - COSTA, I.; ROGERO, S.; TERADA, M.; MARQUES, R.A.
In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel (SS) was investigated for dental magnetic attachments application and compared with that of a comercial universal keeper for dental attachment (Neo-magnet System). In vitro cytotoxicity analysis was performed by the red neutral incorporation method to evaluate one of the criteria of biocompatibility. The results showed that the AISI 444 SS tested presents no cytotoxicity. The corrosion resistance of this SS was investigated by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffer solution (PBS) at 37 oC. The electronic properties of the passive film at the AISI 444 surface were evaluated by Mott-Schottky approach. All tested materials showed passivity in the PBS médium. The NeoM steel showed higher susceptibility to pitting than the AISI 444 SS and this was realted to its composition and microsctructure. The oxide film on the NeoM steel was associated to a higher doping concentration than the passive film on the AISI 444 SS.
Dental tribology evaluation ferritic stainless steels for magnetic implants
2014 - PIERETTI, EURICO F.; MARQUES, ROGERIO A.; WILCKEN, JORGE T. de S.L.; COZZA, RONALDO C.; NEVES, MAURICIO D.M. das
Failure analysis of laser marked AISI M340 stainless steel for odontologic applications
2014 - PIERETTI, EURICO F.; MARQUES, ROGERIO A.; MANHABOSCO, SARA M.; DICK, LUIS F.P.; NEVES, MAURICIO D.M. das