Navegação Ciências Exatas e da Terra por Autor "Vasconcellos, Marcos Antonio Zen"
Resultados 1-12 de 12
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Amorphization of graphite flakes in gray cast iron under tribological load
Hinrichs, Ruth; Vasconcellos, Marcos Antonio Zen; Oesterle, Werner; Prietzel, Claudia (2018) [Artigo de periódico]A gray cast iron disc, which had been submitted to a heavy duty automotive brake test, was examined with energy filtered transmission electron microscopy. A graphite flake in a convenient angular position showed the shear ... -
Comment on "Ion mixing of metal/Al bilayers near 77K"
Vasconcellos, Marcos Antonio Zen; Costa, Jose Antonio Trindade Borges da; Schreiner, Wido Herwig; Baumvol, Israel Jacob Rabin (1989) [Artigo de periódico] -
Estudo da influência dos padrões de emissão das espécies do plasma de carbonitretação nas propriedades superficiais de TiCN
Nunes Filho, Antonio; Braz, Danilo Cavalcante; Hinrichs, Ruth; Vasconcellos, Marcos Antonio Zen; Rocha, Ricardo Cesar da Silva; Alves Junior, Clodomiro (2015) [Artigo de periódico]As intensidades de emissão das espécies N2 +, H, C, NH, N2, Ar e CN do plasma de carbonitretação (usando os gases Ar+N2+CH4) foram medidas por espectroscopia de emissão óptica (OES) em pressão e temperatura constantes ... -
Experimental determination of cross sections for K-shell ionization by electron impact for C, O, Al, Si, and Ti
Limandri, Silvina P.; Vasconcellos, Marcos Antonio Zen; Hinrichs, Ruth; Trincavelli, Jorge C. (2012) [Artigo de periódico]Cross sections for K-shell ionization by electron impact were determined from films of Al, Si, and Ti and their oxides deposited on carbon substrates, for incident energies between 2.5 and 25 keV. The spectral processing ... -
Hardness evaluation, stoichiometry and grain size of titanium nitride obtained with plasma nitriding on Ti-6AI-4V samples
Vasconcellos, Marcos Antonio Zen; Lima, Saulo Cordeiro; Hinrichs, Ruth (2010) [Artigo de periódico]Titanium nitride films were formed on the surface of Ti-6Al-4V discs by plasma nitriding (glow discharge) in different N2:H2 atmospheres at several substrate temperatures. In this study the influence of the process parameters ... -
In situ electrical resistivity of thin-film beta-nial under ar irradiation at 77 k
Costa, Jose Antonio Trindade Borges da; Vasconcellos, Marcos Antonio Zen; Teixeira, Sergio Ribeiro; Scherer, Claudio; Baibich, Mario Norberto (1992) [Artigo de periódico]We report on the dose dependence of the in sítu electrical resistivity of a thin-film NiAl alloy under 120-keV-Ar-ion irradiation at 77 K. The results show two different behaviors. First, the values of resistivity increase, ... -
Ion microproble (SHRIMP) dates complex granulite from Santa Catarina, southern Brazil
Hartmann, Leo Afraneo; Santos, João Orestes Schneider; McNaughton, Neal Jesse; Vasconcellos, Marcos Antonio Zen; Silva, Luiz Carlos da (2000) [Artigo de periódico]Complex polymetamorphic granulites have been dated in the Santa Catarina granulite complex of southern Brazil through SHRIMP study of zircon. This complex is dominated by intermediate-acid plutonic rocks and contains small ... -
Kinectics of ion-induced transformations in β-NiAl thin films as characterized by in situ electrical resistivity measurements
Miranda, Rosalvo Mario Nunes; Vasconcellos, Marcos Antonio Zen; Baibich, Mario Norberto; Costa, Jose Antonio Trindade Borges da (1998) [Artigo de periódico]In situ electrical resistivity of thin film B-NiAl at 77 K under 120 keV Ar1 irradiation has been measured as a function of the total dose for film thickness of 25, 37.5, 50, 62.5, and 75 nm. A qualitative change was ... -
Measurements of L-shell x-ray production cross sections of W, Pt, and Au by 10-30-keV electrons
Campos, Cristiani Silveira; Vasconcellos, Marcos Antonio Zen; Llovet Ximenes, Xavier; Salvat, F. (2002) [Artigo de periódico]We present results from measurements of Lα x-ray production cross sections of the elements W, Pt, and Au by impact of electrons with energies in the range 10–30 keV. The cross sections were obtained by measuring Lα x-ray ... -
A new approach for the determination of multiple cation locations and ordering, using the example of natural and heat-treated columbites
Kinast, Eder Julio; Isnard, Olivier; Cunha, Joao Batista Marimon da; Vasconcellos, Marcos Antonio Zen; Santos, Carlos Alberto dos (2011) [Artigo de periódico]A new approach is proposed to determine unambiguously the location of four cations within the crystal structure of a natural AB2O6 columbite-type compound and derivatives, when submitted to order–disorder transitions caused ... -
Structural and magnetic behavior of ar+-implanted co/pd multilayers : interfacial mixing
Schelp, Luiz Fernando; Carara, Marcos Andre; Viegas, Alexandre da Cas; Vasconcellos, Marcos Antonio Zen; Schmidt, Joao Edgar (1994) [Artigo de periódico]The magnetization behavior of Co/Pd multilayers has been analyzed as a function of the degree of interfacial mixing among the Co and Pd layers. Controlled atomic mixing was induced by low-dose and low-flux ion implantation ... -
The influence of nitrogen to hydrogen ratio and temperature on thickness and phase composition in plasma nitrided Ti-6Al-4V
Lima, Saulo Cordeiro; Hinrichs, Ruth; Vasconcellos, Marcos Antonio Zen (2019) [Artigo de periódico]Ti-6Al-4V was plasma nitrided using several N2/H2 ratios and substrate temperatures. In order to investigate the combined influence of these parameters on phase compositionand thickness of the coatings,the phases in the ...