Crystalline Iron
Mostrando 25-36 de 63 artigos, teses e dissertações.
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25. Síntese de compostos com potenciais atividades biológicas ou magnéticas
This thesis is divided in two parts and presents the results of our studies on the synthesis and the study of biological or magnetic proprieties of a series of ligands and their transition metal complexes. Firstly we prepared a series of dithiacarboxilic acids and their metal complexes to investigate the biological activity of these compounds against fungi,
Publicado em: 2008
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26. Efeito do carbono no processo de nitrocarburização com plasma pulsado da liga metalica AISI H13 / Carbon effect on pulsed plasma nitrocarburizing process in AISI H13 tool steel
This work presents a study on the effect of the incorporation of carbon and nitrogen on he formation of a singlephase homogeneous layer, composed by e -Fe2-3(C,N) carbonitrides, on the top surface of a AISI H13 tool steel. We also present studies on the effect of the incorporation of these elements (C and N) in the microstructure and in the mechanical and ch
Publicado em: 2007
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27. Filmes intermediários para deposição de diamantes CVD sobre aços / Intermediate films for diamond deposition on steel
The present work is inserted in the area of Chemical Vapor Deposition of Diamond thin and freestanding films. The CVD diamond deposition on steel substrates is still a great challenge to overcome. Iron-like materials present negative effects for the CVD diamond growth process, as catalytic effects in the preferential nucleation of the graphitic phase and hig
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/08/2006
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28. Pigmentos nanométricos de alumina dopada com ferro, níquel e manganês / Nanometric pigments of iron, nickel and manganese doped alumina
In the recent years, the necessity of ceramic pigments production with new shades and variable distributions of particle size has increased considerably. The color and size of pigment particles are responsible for important applications in the ceramic industries, resins, cosmetics, dyes, plastics and dentistry materials. In this work, nanometric pigments bas
Publicado em: 2006
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29. Surface treatments of a iron aloy by nitrogen ions / Tratamentos de superficies de uma liga ferrosa por ions de nitrogenio
The objective of this project is to study processes of plasma surface treatment with special emphasis to the differences these techniques might show in relation to others, looking forward to understand the process from surface phenomena. Two kinds of surface treatment have been studied, including three different techniques: ion beam nitriding, pulsed plasma
Publicado em: 2006
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30. Integração de dados de geofísica aérea aplicada à geologia e à prospecção mineral no distrito esmeraldífero de Itabira-Ferros, Quadrilátero Ferrífero, MG.
The Itabira-Ferros area is located in the Quadrilátero Ferrifero region, State of Minas Gerais, and it is known for abundant emerald occurrences. The area is characterized by volcanic metasedimetary sequences of the greenstone belt type (Rio das Velhas Super group) and paleoproterozoic iron formations of Minas Super Group, inserted in granitic bobies (Borra
Publicado em: 2006
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31. Effect of heat treatment on Fe-B-Si-Nb alloy powder prepared by mechanical alloying
The effect of heat treatment on crystallization behavior of Fe73.5B15Si10Nb1.5 alloy powder prepared by mechanical alloying was studied. The powder samples were prepared by mechanical alloying (MA) and for different milling times (1, 5, 25, 70 and 100 hours). Crystalline powders of iron, boron, silicon and niobium were sealed with tungsten carbide balls in a
Materials Research. Publicado em: 2005-06
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32. Caracterização de escorias e recuperação do silicio / Characterization of slag and recovery of the silicon
Metallurgieal Grade Silicon (MGSi) is produced by a well-established industrial process that consists of the carbo-reduction of quartz in a submerged are fumace under high temperature. The process is an intensive energy consumption method (13 - 15 kWh to each kilogram of produced MGSi). After tapered, the MGSi is submitted to some purification stages in orde
Publicado em: 2003
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33. Determinação de cobre, alumínio e ferro em solos derivados do basalto através de extrações seqüenciais
Copper, aluminum and iron concentrations were determined in four geochemical fractions of three different basaltic soils from the northwest region of the Parana State, Brazil. The fractions examined were the reducible manganese dioxide and amorphous iron oxide, crystaline iron oxide, organic and residual. Metal concentrations were determined in the extracts
Química Nova. Publicado em: 2002-07
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34. Aplicação de ressonancia paramagnetica eletronica e da espectroscopia fotoacustica ao estudo de ions Fe3+ em materiais cataliticos e argilosos
During my doctoral period I worked on some experimental fields of physics science. I investigated and characterized several materials of interest for the industry; i.e. the analyzed materials are of technological importance. The present work consists in the application of several material characterization techniques. By this means, it is presented here some
Publicado em: 2002
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35. Indicadores de qualidade estrutural e trafegabilidade de latossolos e argissolos vermelhos. / Indicators of structural quality and trafficability of hapludox and hapludalf.
The soil, besides being one of the basic resources of the natural and agricultural ecosystems, has been considered a finite, fragile and no renewable resource. For this reason the maintenance of its quality has been acquiring great relevance in the last decades. Several soil physical quality indicators have been used with the intention of developing guides o
Publicado em: 2002
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36. Crystallization kinetics of Fe-B based amorphous alloys studied in-situ using X-rays diffraction and differential scanning calorimetry
The crystallization processes for the amorphous metallic alloys Fe74B17Si2Ni4Mo3 and Fe86B6Zr7Cu1 (at. %) were investigated using X-rays diffraction measurements performed in-situ during Joule-heating, with simultaneous monitoring of the electrical resistance. We determined the main structural transitions and crystalline phases formed during heating, and cor
Materials Research. Publicado em: 2001-01