Marcelino P. Nascimento
University of São Paulo
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Featured researches published by Marcelino P. Nascimento.
International Journal of Fatigue | 2001
Marcelino P. Nascimento; R.C Souza; Walter Luis Pigatin; Herman Jacobus Cornelis Voorwald
Abstract Internal residual stresses significantly influence the fatigue strength of coated materials. It is well known that chromium plating is the most used electrodeposited coating for important industrial applications. However, pressure to identify alternatives or to improve the chromium electroplating process have increased in recent years, related to the reduction in fatigue strength of the base material and to environmental requirements. The high efficiency and fluoride free hard chromium electroplating (here called “accelerated”) is an improvement to the conventional process. One environmentally safer and cleaner alternative to hard chromium plating is tungsten carbide thermal spray coating applied by the High Velocity Oxy-Fuel (HVOF) process. To increase the fatigue strength of chromium plated materials, coating thickness and microcracks density are important parameters to be controlled. Techniques as compressive residual stresses induced by shot peening and multilayers, are also used. The aim of this study was to analyse the effects on AISI 4340 steel, in the rotating bending fatigue behaviour, of the: tungsten carbide thermal spray coating applied by HP/HVOF process; chemical nickel underplate, and shot peening process applied before coating deposition, in comparison to hard chromium electroplatings. Rotating bending fatigue test results indicate better performance for the conventional hard chromium plating in relation to the accelerated hard chromium electroplating. Tungsten carbide thermal spray coating and accelerated hard chromium plate over nickel resulted in higher fatigue strength when compared to samples conventional or accelerated hard chromium plated. Shot peening showed to be an excellent alternative to increase fatigue strength of AISI 4340 steel hard chromium electroplated.
Surface & Coatings Technology | 2001
Marcelino P. Nascimento; Renato C. Souza; Ivancy M Miguel; Walter Luis Pigatin; Herman Jacobus Cornelis Voorwald
Abstract In cases of decorative and functional applications, chromium results in protection against wear and corrosion combined with chemical resistance and good lubricity. However, pressure to identify alternatives or to improve conventional chromium electroplating mechanical characteristics has increased in recent years, related to the reduction in the fatigue strength of the base material and to environmental requirements. The high efficiency and fluoride-free hard chromium electroplating is an improvement to the conventional process, considering chemical and physical final properties. One of the most interesting, environmentally safer and cleaner alternatives for the replacement of hard chrome plating is tungsten carbide thermal spray coating, applied by the high velocity oxy-fuel (HVOF) process. The aim of this study was to analyse the effects of the tungsten carbide thermal spray coating applied by the HP/HVOF process and of the high efficiency and fluoride-free hard chromium electroplating (in the present paper called ‘accelerated’), in comparison to the conventional hard chromium electroplating on the AISI 4340 high strength steel behaviour in fatigue, corrosion, and abrasive wear tests. The results showed that the coatings were damaging to the AISI 4340 steel behaviour when submitted to fatigue testing, with the tungsten carbide thermal spray coatings showing the better performance. Experimental data from abrasive wear tests were conclusive, indicating better results from the WC coating. Regarding corrosion by salt spray test, both coatings were completely corroded after 72 h exposure. Scanning electron microscopy technique (SEM) and optical microscopy were used to observe crack origin sites, thickness and adhesion in all the coatings and microcrack density in hard chromium electroplatings, to aid in the results analysis.
Corrosion Reviews | 2003
Renato Chaves Souza; Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald; Walter Luis Pigatin
One of the most interesting alternatives for replacement of hard chrome plating is tungsten carbide thermal spray coating applied by the high velocity oxy-fuel (HVOF) process which presents a safer, cleaner and less expensive alternative to chromium plating. The objective of this research is to compare the influence of the tungsten carbide-17cobalt (WC-17Co) coating applied by high velocity oxy fuel (HVOF) process with that of hard-chromium electroplating on the fatigue strength and abrasive wear of AISI 4340 steel.
Materials Research-ibero-american Journal of Materials | 2002
Marcelino P. Nascimento; Marcelo A. S. Torres; Renato Chaves Souza; Herman Jacobus Cornelis Voorwald
Multiple layer systems of coatings are considered to have larger resistance to crack propagation in comparison to coatings with simple layer. With regard to fatigue, it is possible to improve the resistance of a component with the application of shot peening treatment, whose compressive residual stresses delay or eliminate the initiation and propagation of fatigue cracks. The aim of this study is to analyse the effects on rotating bending fatigue behaviour of hard chromium ¾ electroless nickel multilayer system coated AISI 4340 high strength steel submitted to shot peening pre treatment. Results indicated that the interaction between the shot peening process with the multilayer system was not satisfactory, resulting in intense delamination. Fracture surface analysis by SEM was performed toward to identify the fatigue crack origin, as well as the coating-substrate delamination process.
Journal of the mechanical behavior of materials | 2001
Renato C. Souza; Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald; Walter Luis Pigatin
One of the most interesting alternatives for replacement of hard chrome plating is tungsten carbide thermal spray coating applied by the high velocity oxy-fuel (HVOF) process which consists in a safer, cleaner and less expensive alternative to chromium plating. The objective of this research is to compare the influence of the tungsten carbide-17cobalt (WC-17Co) coating applied by high velocity oxy fuel (HVOF) process and hard-chromium electroplating on the fatigue strength and abrasive wear of A1S1 4340 steel.
Recent Patents on Mechanical Engineering | 2009
Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald
Department of Materials and Technology State University of Sao Paulo-UNESP/FEG, 333, Ariberto Pereira da Cunha Ave., CEP 12500-000, Guaratingueta City, Sao Paulo State
Journal of Materials Processing Technology | 2011
Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald; João C. Payão Filho
International Journal of Fatigue | 2010
Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald
Archive | 2006
Marcelo A. S. Torres; Marcelino P. Nascimento; Herman Jacobus Cornelis Voorwald
Plating and Surface Finishing | 2001
Marcelino P. Nascimento; H. J. C. Voorwald; R. C. Souza; W. L. Pigatin