EM - Escola de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6

Notícias

A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.

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Filtros

2001 - 20022

Configurações

Autor: search.filters.author.Craievich, AldoAssunto: search.filters.subject.Synchrotron radiation

Resultados da Pesquisa

Agora exibindo 1 - 2 de 2
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    Phase transitions in Nb rich coating produced by laser alloying : a synchrotron radiation diffraction study.
    (2001) Costa, Adilson Rodrigues da; Craievich, Aldo; Vilar, Rui
    A great variety of studies have been performed in order to develop new materials with high performance in many adverse conditions such as wear and corrosive environment coupled with high temperatures and high stress levels. A strong scientific and technical effort is currently dedicated to develop wear and corrosion resistant surfaces to provide components having good behavior in such extreme working conditions, we have chosen laser alloying and prepared Nb rich coatings upon a nodular cast iron microstructure. The new tailored material is in fact a composite having a very hard coating covering a traditional iron base material. If the material is submitted for thermal cycling, it is imperative to know the phase transformations during heating/cooling cycles, as well as, during long periods of permanence at high temperatures. According to these guidelines, we performed an X-ray diffraction (XRD) study using the XRD beam line of the National Synchrotron Light Laboratory (LNLS, Brazil). The analysis of the XRD pattern indicates the presence of niobium and niobium carbides (Nb, NbC, Nb2C) from room temperature up to 750°C.
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    Niobium and chromium rich coatings tailored by laser alloying : XRD analysis at high temperatures.
    (2002) Costa, Adilson Rodrigues da; Craievich, Aldo; Vilar, Rui
    Laser treatment technologies have been widely used to modify superficial layers of different materials. In this work we prepare Nb and Cr rich coatings according to laser alloying technique using cast iron as substrate material. Nb and Cr are intensive used in order to overcome challenges like good chemical and mechanical performance at high temperatures. Following laser alloying the surface-modified samples were submitted to an “in situ” XRD analysis under controlled high temperature and atmosphere. The phase transitions registered point to transformations that do not implies formation of fragile phases or cracks induced by high volumes modifications.