Materials Science Forum Vols. 727-728

Abstract: This research aims to study the process of incorporation of the metal iron contained in electric arc furnace dust (EAFD), by addition in hot metal at a temperature of 1,400 degrees Celsius altering experimental conditions such as how to add the EAFD (“as received” and in the form of briquettes), the percentage of EAFD to be added (10, 20 and 30% of initial weight of sample pig iron). The time of withdrawal of the sample of pig iron and slag (30 minutes after the addition of EAFD). Previously, the EAFD will be characterized using the following techniques: chemical analysis, particle size analysis, X-ray diffraction, scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) microanalysis. After characterization, the electric arc furnace dust to be added to the bath of liquid iron, will be divided into 2 types: the first order of addition will be in the form "as received" from the plant and the second is through the agglomeration of EAFD in the form of briquettes. The achievement of fusion experiments in laboratory scale will take place in a vertical tubular furnace with temperature control. The fusion experiments to assess the incorporation of the metal iron will use graphite crucibles. A flow of inert gas (argon) will be maintained inside the furnace during the experiments. It is expected that the results obtained at the end of the research allow the evaluation of the iron metal incorporation of electric arc furnace dust in pig iron bath.

Abstract: The use of vulcanized rubber products is widely spread in the industry and in the society. Tires, shoes, tennis and other are examples of it. Most of the raw materials used in the formulations of vulcanized rubber products come from the synthesis of natural raw materials consuming time and energy and also generating CO₂ emissions during the respective transforming processes. The main reinforcing material used in rubber formulations is the carbon-black which is a petroleum derivative obtained by the incomplete burning of the fossil fuel. This paper show some results obtained after replacing all or part of the carbon-black by carbonaceous nanoparticle minerals in rubber formulations.

Abstract: Quaternary ammonium compounds are widely used as antiseptic agents, disinfectants, detergents and preservatives. In addition, quaternary ammonium compounds are often used as algaecides, and chloride dodecyl dimethyl benzyl ammonium chloride (benzalkonium chloride) is the most effective against these microorganisms. However benzalkonium chloride is not used as surface algaecide compound due its high hydrophobicity, bring on high leaching of this compound when the surface is exposed to high humidity. Currently, compounds such as diuron and s-triazine are used as algaecides, but had been detected in coastal regions in high levels concentration showing the leaching of these biocides. Then raise the necessity to develop a new algaecide to overcome the failings of leaching of the compounds used nowadays. Nanomaterial as organoclay is an excellent alternative because they have highly hydrophobic. Therefore in this work was synthesized a new nanomaterial using benzalkonium chloride, which was applied in a house paint formulation. The nanomaterial was characterized by the techniques of X-ray diffraction and thermo gravimetric analysis. The biocide capability as well as resistance to weathering of the nanomaterial was checked thought microbiological and leaching test. The new nanomaterial synthesized in this study had a high potential to be used as a microbial agent in paints.

Abstract: The thermal and mechanical properties assessed respectively by dynamic mechanical analysis and flexural bend tests as well as the abrasive behavior obtained by wear tests of diamond particles incorporated epoxy matrix composites were investigated. Diamond particles with sizes in the range of 45 to 115 µm, synthesized at high pressure and temperature, were mixed in amounts of 20 and 40 wt% with dyglycidyl of the bisphenol A, DGEBA, epoxy resin cured with stoichiometric ratio of tetraetylenepentamine, TEPA, hardener. These composites were dynamic mechanical, DMA analyzed and three points bend tested. The behavior of the composites as abrasive tool for industrial polishing of ornamental rocks was evaluated by wear tests. The results showed an improved performance of the DGEBA/TEPA composites with incorporation of diamond particles.

Abstract: Diamond embedded cutting saws (DCSs) are basic tools commonly used in every ornamental stone processing operation from the extraction of the quarry block to the finishing of tiles. Diamond particles are the hard and abrasive essential component that has to be well adhered to the saw matrix, whether metallic, ceramic or polymeric. This work presents a computer simulation analysis and experimental design for an optimized manufacturing process of DCSs. This discrete simulation assesses the basic parameters involved in a possible industrial production in order to maximize the dynamics of the system and operational rules needed for best final products.

Abstract: Due to the environment and economical questions, the use of cadmium coatings, in the aeronautical and automotive industries, has been prohibited. In this context, ZnNi coating alloys have been propose to replace cadmium coatings due to its properties. However, in order to postpone the corrosion of ZnNi alloy, hybrids films obtained by sol-gel process have been studied. In this work, hybrids films were obtained on ZnNi coating by dip-coating process from a sol constituted of alkoxide precursors: γ-methacryloxypropyl-trimethoxysilane and tetraethoxysilane with cerium nitrate addition (0.01 M). Two withdrawal speeds of substrates from the sol were applied: 5 cm.min^-1 and 10 cm.min^-1 .The films obtained were evaluated by morphological (SEM and AFM) and electrochemical characterization. The superior corrosion protection performance was observed for the ZnNi/hybrid film system obtained with withdrawal speed of 10 cm.min^-1, thought, the presence of discontinuities were observed in this film.

Abstract: The ultra high molecular weight polyethylene (UHMWPE) has a molecular mass of the order of a millions of grams per mole. So, UHMWPE presents prominent properties, for instance, abrasion and impact resistance. However, due to its very high viscosity in the melt state, the preparation of composites by conventional extrusion and injection molding is not possible. Therefore, in this work we studied the possibility of incorporating montmorillonite (MMT) into the matrix of the UHMWPE in the solid state, via high energy milling. The formulations were prepared in Attritor mill by milling UHMWPE reactor powder and MMT. The samples were characterized by bulk density, XRD, AFM and SEM. Results show that this route of processing was effective to incorporate MMT into the matrix of UHMWPE.

Abstract: This research is to obtain nanocomposites of HDPE/bentonite clay. Inorganic polymers reinforced with materials are of great interest due to their applications in automotive, and electrical and electronic industries. The nanocomposites were produced by melt intercalation with different percentages of clay and compared with pure HDPE. Clay was used as modified and unmodified and it was characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The obtained nanocomposites were characterized through thermogravimetry (TG). It was verified by XRF that clay performed compositions of bentonites characteristics. By XRD, it was observed increases basal spacing for organoclay. By TG, in general, it was verified that the nanocomposites presented greater thermal stability in relation to HDPE.

Abstract: Nanocomposites are hybrid materials that can be obtained with, three, two or bust one-dimensional in nanoscale found in particles dispersed in the matrix. By presenting a nanometric structure, this new class of materials may have only properties, different from traditional composites and their constituents, which may be established in the synthesis process. The aim of this work is prepare nanocomposites of HDPE/ bentonite clay by melt intercalation technique. Systems were evaluated for the presence of untreated clay and chemically treated (organoclay) with two different types of quaternary ammonium salts, Cetremide and Dodigen. In the preparation of nanocomposites were obtained concentrated using a high speed mixer and then the nominal percentage of clay was dispersed in a twin screw extruder corrotacional. The systems were characterized by X-ray diffraction and mechanical properties. The XRD patterns of nanocomposite of HDPE/organoclay suggest a not intercalated structure. The mechanical properties of nanocomposites presented reducing values in relation to pure polymer.

Abstract: In the present work residual powders of diverse industries are characterized from the environmental and physicochemical point of view, in order to determine the properties of them and establish the feasibility of reutilization or recycling. Cinders of additives, waste of scrap shredding process, LD converter steel slag and other powders of industrial processes were characterized by using optical and electronic microscopic techniques, semiquantitative chemical analysis, particle size distribution, X-ray diffraction analysis, thermal and thermogravimetric analysis, leaching test, among others. As a function of the obtained results some possible ways for recycling or reuse of these residual powders were proposed.