The synthesis of alloys with nominal composition for Y1-xSmxCo5 by means of arc furnace and melt-spinning, is of critical scientific importance due that if replaced partially or completely the Samarium by the Yttrium is possible understand what contribution the earth element rare to the exchange interactions that guide to increased remnant magnetization in a nanocomposite. The alloys of Y1-xSmxCo5/Co obtained by melt-spun were characterized by x-ray diffraction with a compact hexagonal crystal structure the CaCu5 type. The alloys for nanocomposites of Y1-xSmxCo5/Co ribbons show ferromagnetic behavior with good magnetic properties, order to demonstrate this the magnetic properties were measured using a pulsed field magnetometer applying a high magnetic field in order to obtain a saturated magnetization curve and a high coercivity of 0.69 MA/m and an enhanced remanence of σr/σsat ratio equal to 0.57 were determined.

Equipment wear is caused by the disintegration of material due to the contact between the machines components and the ore, resulting in stress to the surface of the material. Wear causes loss of efficiency, vibration, misalignment and, in severe cases, cracks that may lead to fracture and damage to the equipment. In mining, wear is caused by operational problems in which generate high costs. Some researchers studied white cast iron alloys with high chromium and the addition of niobium for wear plates manufacturing and therefore, plates to protect structural parts of the equipment have been developed. This study presents the characterization of the microstructure of two alloys of white cast iron with high chromium containing 3.8 wt.% C and 27.1 wt.% Cr and the addition of 0.9 wt.% Nb (alloy 1) and 1.6 wt.% Nb (alloy 2), respectively. Samples of the two alloys were subjected to metallographic tests, microhardness and abrasion type rubber wheel tests, according to the ASTM: G65-91 standard. Complexes carbides have been identified in both alloys. The results of microhardness and wear resistance tests were correlated and identified the effect of niobium addition. The findings suggest that the addition of niobium in these alloys contributes to the formation of NbC and increase of Cr in the matrix; consequently increase in the hardenability of the material. The wear resistance of alloy 2 was 47.95% higher than alloy 1 in abrasion type rubber wheel tests. It demonstrates that the increase of niobium in the alloy has contributed to improve wear resistance due to the substantial change in the microstructure and distribution of NbC carbides.

The surface quality of a heat treatable Al-Si-Mg alloy by means compression tests at 450°C was evaluated. Samples were obtained from an ingot with unidirectional solidification in order to obtain a microstructural gradient influenced by the cooling and solidification rate. The samples were heat treated by homogenization at 520°C for 4 hours prior to deformation by compression. Inverted optical and scanning electron microscopes were used to assess the surface damage of deformed samples.

Analysis of deformed surface indicates a greater influence of microstructural refinement on hardening rate. It was found that the samples solidified at high cooling rates showed no defects, but at low cooling rates produced growth of grain size and intermetallic phases and thereby the high incidence of cracks in the surface.

The synthesis of Fe3O4-Ag bimetallic nanoparticles by chemical reduction was carried out. Fe nanoparticles were obtained using Fe (III) Chloride hexahydrate (FeCl3•6H2O) as precursor and sodium borohydride (NaBH4) as reducing agent, subsequently, a solution of silver nitrate (AgNO3) was added to the reaction. The synthesis methodology employed in this case, is a modification of chemical reduction method. Through this procedure has been possible simplify the synthesis route used to obtain bimetallic systems such as Fe3O4-Ag. Particles with semi-spherical morphology were observed. High-resolution transmission electron microscopy (HREM), ultraviolet visible spectroscopy (UV-is) and quasi-elastic light scattering (QELS) techniques were employed for the structural characterization of Fe3O4-Ag nanostructures. Some models presented describe and prove the formation of the Fe3O4-Ag alloy type structures.

The possibilities of Ni as contact material in electronic applications has motivated the interest on the intermetallic phases of the Ni-Sb system, in relation to their use in lead free micro-soldering processes. In this work, a detailed theoretical study of the cohesive and thermodynamic properties of the compound Ni3Sb in the (cF16) Fm-3m structure is reported. To this aim, the Full Potential Linearized Augmented Plane Waves method, within the framework of the Density Functional Theory and both Generalized Gradient and Local Density approximations, has been applied. The structural parameters, cohesive and elastic properties of this compound and its constituent elements have been determined. In particular, the equilibrium structural properties are determined through the minimization of the energy, including the full relaxation of the internal degrees of freedom of the cell. It is shown that the calculated properties agree well with the available experimental data. Moreover, various contributions to the electronic density of sates are studied. On this basis, a discussion is presented of the bonding characteristics of this compound, in the framework of the current ideas about cohesion in p-d bonded intermetallics.