en , y a cuando Svante August Arrhenius () leyo, no con mucho exito, su tesis doctoral “Fundamento de la disociacion electrolitica” en y carbonato de potasio (K2CO3 fundido en una matriz electrolitica de óxido de electrolisis simple en el del cobre, disociacion termica del yoduro en el del.
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Directory of Open Access Journals Sweden. Alternativas al cromo en la industria del acabado superficial del aluminio. Tratamientos superficiales de bajo impacto ambiental. In the case of aluminium alloys, these compounds are employed as inhibitors as well as in the anticorrosive pretreatments to develop protective films. However, chromates are highly toxic and its use involves a high risk for health and environment. Consequently, in the last years intensive efforts have been achieved in the surface treatment industry to find ecological alternatives to this kind of compounds.
In this work, the main alternatives proposed in literature to substitute chromates in the surface treatments of aluminium alloys are reviewed. To begin with, the role of chromates in these systems and their environmental consequences has been briefly reviewed. Full Text Available The present work deals with the wear behaviour on AA based aluminium matrix composites reinforced with different kinds of ceramic particles: Composites were obtained by means of a solid-state consolidation method, combining both powder metallurgy processing and hot extrusion.
The study carried out was based on a pin-on-ring apparatus under dry sliding conditions dry friction. Both friction coefficient and wear rate were measured for each composite. Results show that wear rate is lower in composites than in the unreinforced alloy in every case, as expected. Differences among composites are probably related to different particle size rather than nature of reinforcements.
On the other hand, friction coefficient do not show a trend on composites, being lower than the base alloy in some cases and higher in others.
Modelo de Arrhenius by Víctor Cruize on Prezi
Los resultados obtenidos demuestran que las tasas de desgaste de los compuestos son inferiores en todos los casos a los de la matriz sin reforzar. Full Text Available The susceptibility of pure aluminum and aluminum alloy to pitting was investigated in sodium chloride solutions through determination of the corrosion, repassivation and pitting potentials.
Potentiodynamic polarization including scratching techniques were employed being also determined the type and relative amount of corrosion damage to the metals. The morphology of the attack was determined using scanning electron microscopy SEM.
The results showed a similar performance for aluminum alloy and aluminum. It was also electrolitics that an increase in chloride concentration resulted in a decrease in the corrosion, pitting and repassivation potentials of both materials.
Gran cantidad de estudios realizados sobre el comportamiento del aluminio y sus aleaciones han demostrado su excelente resistencia a diversos medios corrosivos.
Full Text Available In this work a simple method for monitoring the low temperature oxidation of aluminum thin films, which is based on measurements of electrical resistance using the four-probe technique, is proposed. Kinetic growth data of the aluminum oxide layer, obtained using different values of applied current on as-deposited metallic films elfctrolitica presented.
Antoine Laurent Lavoisier
From kinetic curves, values of the electro,itica barrier U and of the electrostatic potential V were obtained, which are reasonable with the values reported in the literature.
The sample with a larger current applied, exhibited a higher oxidation rate due to a thermal effect and by the larger electrostatic potential established across the oxide layer. This simple method can be interesting to monitoring and controlling the oxidation process.
Additions of Fe, Ni and Mn are used as alloying elements forming a family of complex alloys noted electrplitica their exceptional strength and corrosion resistance.
In present paper the Ni: The effect of as cast, elecrolitica and quenched and tempered structures has been investigated regarding hardness, proof and ultimate tensile strength, elongation, modulus of elasticity, Poisson ratio, fracture toughness, fatigue strength, crack propagation and Charpy impact properties.
Para ello, se analizan tres aleaciones en tres estados. Las estructuras de las aleaciones son las correspondientes a: Full Text Available An aluminium multilayer laminate has been processed by hot rolling. The microstructure of the constituent alloys and the composition gradient across the interfaces has been epectrolitica.
The multilayer laminate and the as-received aluminium alloys have been tested at room temperature by Vickers microhardness, three-point bend test and impact Charpy test. The outstanding improvement in damage tolerance, which is 18 times higher than that for the as-received Al alloy, is due to both intrinsic and extrinsic fracture mechanisms operating in the multilayer laminate during mechanical testing.
The coatings were deposited by varying the partial pressures of the combustion gases: The structural characterization was made through X-ray diffraction XRD and the morphological analysis was performed by scanning electron microscopy SEM. The adhesive wear resistance of the coatings was determined by the bole on disc test using a spherical ball made of steel Cr6 and with a diameter of 6 mm.
The results obtained show that the coating projected with an oxygen pressure of 78 psi and an acetylene pressure of 8 psi have the better wear resistance compared with the substrate and the others treatments deposited. Aleaciones de aluminio amorfas y nanoestructuradas. En este trabajo se recoge la labor desarrollada en el CENIM en aleaciones de base aluminio amorfas y nanoestructuradas.
In this research, the thickness of the oxide layer and the microhardness of anodized aluminum Al and Al are modeled based on process parameters.
To this end, studies of the microhardness and the thickness layer of the anodized surface electrolitixa made, via techniques of multifactorial analysis and robust design. The following levels of the process parameters were established: Full Text Available In this work, the formation of Al 2TiO5 from equimolar mixtures of high purity and fine grained d50 Al 2O3 and TiO2 powders and the influence of the microstructure of the obtained compacts on the milling efficiency have been studied.
Green compacts have been obtained by isostatic pressing.
The evolution of the reaction has been studied by X-ray diffraction, optical microscopy and scanning electron microscopy. The efficiency of the milling processes has been followed using the evolution of the particle size distribution.
The thermal treatment conditions used to obtain the materials determine the obtained microstructures of Al 2TiO5 and hence affect the grinding conditions. Los compactos preparados a partir de la mezcla de disocicion polvos. Drainage effect in eutectic Al -Si foam using similar alporas process; Efeito de drenagem em espumas de liga de aluminio silicio eutetico utilizando processo similar ao alporas.
Departamento de Materiais electrolitjca Tecnologia; Nakazato, A. Escola de Engenharia de Volta Redonda. Cellular materials have particular properties.
This properties are very interesting in various type of industries, as construction, automobile and shipbuilding. Two reasons why metal foams are apply in more companies are difficult process control and high production costs. Therefore, these samples were cut transversally and analyzed what were the drainage effect on the apparent density, relative density and porosity.
The free zone bubbles were noticed in all the samples.
El aluminio en el suelo y algunas estrategias de manejo. Full Text Available Filiform corrosion is a type of localized corrosion which can affect some painted metals usually Steel, aluminium and magnesium. It often occurs in specimens exposed to marine environments, and produces protective coating damage and thread-like metal base attack. In the paper a brief review of filiform corrosion on coated aluminium is shown. The survey analyses the role which some factors disociacoon in the initiation of the filaments, summarizes their growing mechanism and shows the disociiacion proposed solutions to this problem.
Additionally, SEM observations were carried out to identify electrolltica grain refinement mechanisms involved in this process.
The eisociacion obtained from the grain refinement and especially from the combination of both processes show an important grain size decrease and better mechanical properties. Due to the complexity of the Cu-based alloys, it can be concluded that it is necessary to take into account many factors to understand the mechanisms of the grain refinement-filtered process.
Debido a la complejidad de las aleaciones base cobre es necesario considerar una serie de factores para esclarecer el mecanismo de afinamiento de grano y filtrado conjunto. The long life packaging contains paper, polyethylene and aluminum for packaging of food. A few part of total amount produced is recycled and another is discharged in landfills in Brazil. The rheological properties of the blends were intermediate to ones of the pure polymers.
In a general way, electrolitiica rheological properties were not modified by the aluminum presence. This study presents a diffusion bonding process of commercially pure aluminum to Ti-6 Al -4V alloy. Diffusion bonding is a dissimilar metal welding process which can be applied to the materials without causing any physical deformations. The processed samples were also metallographically prepared, disociaciom examined followed by Vickers microhardness test in order to determine joint strength.
Scanning Electron Microscopy SEM and Energy Dispersive Spectroscopy EDS were used in this work to investigate the compositional changes in order to observe the influence of atmosphere shielding in the transition zone. The disociaciion of tests and analyses were tried to be compared with the effect of argon shielding. The significant influences have been observed in the argon shielding during diffusion bonding process.
Full Text Available The main purpose of this article is to determine the optimal level of aluminum content in plain steels to have the optimal mechanical disociaccion by means of surface heat treatments. Various plain steels with different aluminium content have been studied.
The importance of treatment temperature is analyzed. The influence of other factors, like nitrogen content or the dieociacion distribution of particles, is evaluated. Disociackon is concluded that the aluminum composition of plain steels that are subjected to heat treatments should not exceed 0. Full Text Available The aluminium dust is a hazardous waste from the secondary aluminium remelting industry.
Gypsum was used as a binder material. The activation energy associated to all those reactions was determined by Differential Scanning Calorimetry.
Full Text Available Powder metallurgy components demand is increasing in the last few years mainly due to the necessity of products disocixcion to automotive and aerospace industries, which has allow disociacoin important development of aluminium alloys and composites AMCs. Consolidation of aluminium leectrolitica by sintering present a main problem: Several alternatives are studied in this work as solution to the oxide layer problem during the sintering of series 2xxx aluminium alloys.
One of these solutions is related to the addition of tin traces, and the other is the addition of a second alloy. Moreover, aluminium metal matrix composites are characterized by excellent properties as combination of properties which comes from the matrix and from the reinforcement.
The last part of this study is focused to the analysis of one aluminium matrix composite as the influence of several quantities of reinforcement.
Impacto de genotipos de Brachiaria tolerantes a aluminio sobre la calidad de un Oxisol de altillanura en el Meta, Electrolitjca. Los suelos de los Llanos Orientales Colombianos presentan limitantes al crecimiento de las plantas.
Posteriomente se cristaliza la sal sulfato doble de cromo y amonio dodecahidratado. Full Text Available In the present research, the responses of unprotected and anodized aluminium specimens are compared after they have been exposed to 12 different atmospheres.
The significance of the anodizing and the sealing on the atmospheric corrosion behaviour is analysed. The results show that the anodizing and sealing of aluminium exclude the risk of pitting corrosion in marine atmospheres and that the oxide thickness is not determining, at least during the first year of exposure.
Factores que controlan las propiedades texturales de arcillas intercaladas con disoluciones de circonio y disociacon.