[PDF] Top 20 Mat. Res. vol.2 número3

... This special issue of Materials Research present arti- cles selected from the First Brazilian Symposium on Structology, held in Belo Horizonte, in October 1998.. The Symposium was ideali[r] ... See full document

... These results can be explained taking in account at least three factors. Firstly, as already discussed from the TEM results (Table 1), the presence of platinum enhances the reduction of the nickel cations forming more ... See full document

... observed. One α phase field treatment produced a fully-la- mellar structure represented in the Fig. 5 c; dendrites are no longer visible after this treatment which may be supposed as capable of producing an equilibrium ... See full document

... In this work it was evaluated the influence of the type and concentration of the acid catalyst and the gelation temperature on the structure of pores of silica gels obtained with TEOS. The values of the major structural ... See full document

... Figure 2 presents the results of specific surface area as a function of the lead ...Fig. 2, the specific surface area decreases as the lead content increases and, for the same pH value, it was observed no ... See full document

... The starting powders used to produce the composite pellets were alumina A16 (Alcoa, USA) and tetragonal zirconia TZ3Y (Tosoh, Japan), whose average particle sizes are 0.5 and 0.3 µm, respectively. The volumetric zirconia ... See full document

... The apparent dependence of the density of the Gd and Yb doped samples on the sintering time at 1500 °C is shown in Fig. 6. While the Gd doped sample shows an almost constant density with sintering time, that of the Yb ... See full document

... Sintered nickel powder is proposed to be used as porous wicks in heat pipes and capillary pumps. In this work the manufacturing procedure for tubular wicks for capillary pump application is discussed. The porosity, ... See full document

... Nickel-zinc ferrite has spinel structure. There are eight tetrahedral sites occupied by non-magnetic Zn 2+ ions and sixteen octahedral sites occupied by Ni 2+ and Fe 3+ ions. Due to the synthesis process or ... See full document

... Granular systems composed by nanostructured magnetic materials embedded in a non-magnetic matrix present unique physical properties that depend crucially on their nanostructure. In this work, we have studied the ... See full document

... The sequence of geometric states, expressed in terms of how the surface area and integral mean curvature vary with the volume of the phase, is seen to be determined in a complex way by r[r] ... See full document

... (in weight), the measured ratios were Mg/Si = 1.8 and Mg/O = 1.0 for the continuous layer and Mg/Si =1.9 and Mg/O = 1.1 for the dark regions at the sub-layer. These facts strongly suggest that the dark particles and the ... See full document

... It shows the actions to be taken as consequence of decisions listed in a systematic way 5 . Table 2 shows a simplified decision table to choose the type of model that will be used in the study of any ... See full document

... to avoid artificial grain coalescence. We ran nine series of simulations, with values of Q from 8 to 30,000. The results are shown in Fig. 6. It is clearly noticeable that the value of Q alters the kinetics of grain ... See full document

... nized that this approach is only “statistically true”, and that there are local interactions not following this rule, these mean field approaches neglect these events. Moreover, the collective behavior should also be ... See full document

... The areas inside two relatively high peaks represent the catchment basins (CBs), i.e., in this image the grains, whose boundaries should be detected. A closer inspection of this profile shows that the non-significant ... See full document

... (retention vol- ume) was monitored as a function of time and the concen- tration of solution that comes out of the columns was analyzed by measuring its refractive index and comparing it to the pure ... See full document

... The oxidation of NiAl, NiAl-20at.%Fe and NiAl-30at.%Fe at 1000-1100 °C in air has been studied. Pure NiAl shows excellent oxidation resistance due to the formation of an Al 2 O 3 layer. NiAl-20Fe also shows good ... See full document

... Similar behaviour has been already reported for cop- per 10 . However, the nominal stress (Σ) - nominal strain (e) curves (Fig. 2) presents a behaviour not commonly ob- served in tension: samples with prestrain ... See full document

... showed that a great part of the Si atoms exist as silanol groups which originate resonance peaks at -110, -100 and -91 ppm. The presence of Al atoms may generate Si(3Si,Al) and Si(2Si, 2Al) environments which might be ... See full document