Greases are essential in the electrical industry for the purpose of minimizing wear and coefficient of friction (COF) between the components of circuit breakers. Nowadays some researchers have explored the addition of nanoparticles to enhance their tribological properties. In this study, tribological tests were performed on different greases employed for the electrical industry. CuO and ZnO nanoparticles were homogeneously dispersed into the greases, varying their concentration (0.01 wt.%, 0.05 wt.%, and 0.10 wt.%). A four-ball tribotest, according to ASTM D-2266, and a ball-on-disk tribotest, according to ASTM G-99, were performed in order to analyze the wear scar diameter (WSD), COF, wear mass loss and worn area. The worn materials were characterized with an optical 3D profilometer measurement system. Anti-wear properties were enhanced up to 29.30% for the lithium complex grease (LG) with no nanoparticles added, in comparison with the aluminum complex grease (AG), providing a much better tribological performance; in the ball-on-disk tribotests, a 72.80% and a 15.74% reduction in the mass loss and COF were achieved, respectively. The addition of nanoparticles was found to provide improvements of 5.31% in WSD for the AG grease and 34.49% in COF for the LG grease. A pilot test was performed following the security test UL489, achieving a reduction of 45.17% in the worn area achieved by LG grease compared to AG grease.

Instrumented indentation of a high purity Fe surface with unresolved surface deformation due to mechanical polishing is compared to the same grain surface annealed at increasing time and temperature. The differences in indentation size effect behavior with annealing are correlated with hardness and electron backscatter diffraction measurements as independent measures of surface layer deformation. It is found that the Nix Gao plot evolves from non-linear (bilinear) towards the predicted linear relationship as the surface deformation is removed. The experimental observations are rationalized by inclusion of a depth dependent, polishing induced forest dislocation density within the Nix-Gao model.

Research focus in recent years on magnetic behaviour of transition metal (TM) ions embedded in semiconductors has shifted from intrinsic effects to extrinsic effects such as the formation of nanoclusters of the TM ions and the influence of the host matrix on their magnetic behaviour. Our studies, using conversion electron Mössbauer Spectroscopy and magnetization measurements, on SiO2 and Al2O3 substrates implanted with 4 at. % Fe, show ferromagnetic behaviour of α-Fe clusters in amorphous SiO2, but α-Fe2O3 clusters displaying superparamagnetic relaxation in crystalline Al2O3.

This contribution deals with the fabrication of a new generation of supercapacitors for harsh environment (avionics) based on nanostructures layers fabricated by spray-gun deposition method. Thanks to the fabrication of electrodes using spray-gun and the utilization of specific ionic liquids developed at Thales, we were able to achieve a capacitance of 20F/g (for a whole cell) and a power of 40kW/kg using carbon nanofibres (CNFs) mixed with reduced graphene oxide (RGO). These results are not the higher values obtained in literature but they are extremely interesting considering that the final device needs to stand temperature between -55°C and +105°C for avionics applications and that no commercial supercaps in the world are able to work in this interval. Only using these ionic liquids and the specific electrodes, it is possible. These supercapacitors were fabricated using spray-gun deposition method which is an extremely interesting technique from an industrial point of view considering that it can be easily implemented in roll-to-roll fabrication.

A thermoset polymer can be used for specific applications by creating a unique chemical composition that is designed for certain characteristic environments. To know the behavior of a thermoset polymer, it is necessary to thermally analyze its behavior during the curing process, as well as its mechanical behavior under certain loads that are applied in its field of application. In this study, the epoxy resin X was created at high temperatures, which there was no record of its thermal or mechanical behavior; the resin was analyzed to determine if it was possible to make a reduction in its curing cycle that was at temperature of 425° F with a time of 24 hours. As a result, through thermal analysis such as Differential Scanning Calorimetry (DSC), rheometry, Thermogravimetric Analysis (TGA) and Dynamic Mechanical Thermal Analysis (DMTA); as well as mechanical analysis, such as stress, hardness and planar cutting tests; it was possible to reduce the curing cycle of resin X, which is used in aerospace generators, from 24 hours at 425 ° F to 8 hours at 425 ° F. In the same way, this reduction of the cure cycle was verified by means of a qualification of a product that involved the reduction of the curing cycle of the epoxy resin obtaining very similar results to the original ones, verifying that the change of curing in the epoxy resin did not affected the functioning of the component. This methodology can be used and applied for the study of thermoset polymers that are used in several industries such as aerospace, automotive, among others.

Characterizing individual ligaments’ behavior during deformation of nanoporous (np) structures remains crucial in further understanding the mechanical response of such materials. In this paper, we report, for the first time, quantifiable results describing the reorientation of ligament structure in np gold (np-Au) subjected to nanoindentation, based on characterization by electron backscatter diffraction (EBSD) orientation mapping. The analysis was performed on a cross-sectioned face at the center of an indent, after specimen preparation utilizing focused ion beam (FIB) techniques. This work provides insights into how the np structure accommodates the material volume displaced during nanoindentation, as well as the strain propagation under the indent. This new knowledge will be fundamental to optimizing utilization of the nanoindentation technique for measurement of np materials and, in particular, np thin films.

Development of solid polymer electrolytes has potential applications for battery technology. Membranes should be environment friendly and also have high conductivity. We use chitosan, cellulose and graphene in this research. In this work, 1% (w/v) of chitosan powder and 1.5% (w/v) of acetic acid were dissolved in double distilled water. The solution was heated to 60°C under constant stirring until the chitosan powder was completely dissolved and a semi-transparent thick chitosan solution was obtained. To this chitosan solution, appropriate amounts of graphene (grade H5-XG Sciences) was added to have 5, 10, 20 and 30% graphene (weight with respect to chitosan). The solution was sonicated for dispersing graphene and then 100ml of it was poured on plastic dishes with and without cellulose fabric in it. The films were dried by slow evaporation technique. The sample thickness varied from 200 to 300µm. SEM images showed that chitosan film formed on cellulose and had grid like structures. Chitosan deposited more on the fibres of the cellulose. This is attributed to the rectangle shaped micro pores of cellulose fabric. From the cross section of the films, it was observed that graphene arranged in stacks along the plane of the cellulose fabric and the fabric became darker as graphene concentration increased. The dielectric properties such as dielectric constant, impedance, conductivity and dissipation factor were measured from 102 - 106 Hz. The conductivity of the sample increased as the frequency increased. The conductivity of the samples at room temperature increased with increase in graphene concentrations. The conductivity varied from 10-8 to 10-5 S/Cm as the graphene concentration increases from 0 to 30%. Hence conductivity increases significantly as graphene concentration increases. From the dissipation factor for the films, the relaxation process could be observed in the frequency ranging from 102 to 105 Hz. It is observed that as frequency increases, the relaxation tend to shift towards higher frequency indicating that graphene affects the relaxation of the polymer nanocomposite. At high frequency (106Hz) dissipation factor for cellulose fabric, chitosan in cellulose, chitosan with 5% graphene in cellulose, chitosan with 10% graphene in cellulose, chitosan with 20% graphene in cellulose, chitosan with 30% graphene in cellulose are 0.14, 0.19, 0.4, 0.8 and 1.38 respectively. This shows that dissipation factor increases as the graphene concentration increases. This implies that graphene improves heat dissipation in these films. The dielectric constant was observed to be maximum for chitosan with 30% graphene in cellulose indicating that the graphene may assemble into percolation networks at higher concentrations of graphene (20 and 30%).

The non-equilibrium self-consistent generalized Langevin equation (NE-SCGLE) theory of irreversible processes in liquids has been proposed as a theoretical framework capable of predicting the age- and preparation-dependent properties of highly ubiquitous non-equilibrium amorphous solids, such as like glasses and gels. By this formalism, we discuss the main kinetic features of the irreversible relaxation of simple liquids involved in the arrested spinodal decomposition of suddenly and deeply quenched. At some lower temperature we identify, by means of a latency time within which particles retain a finite apparently stationary mobility, the crossover from full phase separation to arrested spinodal decomposition which leads to recognize the onset of gelation.

By using electrochemical tests, small signal variations were study by digital signal processing techniques. Electrochemical noise and electrochemical polarization curves were very useful to obtained electrochemical behavior of alloys, but the low signal levels of measurements obtained showed that some of the information was not likely to be measured and, therefore, not being able to identify. Graphene oxides (GO) samples were prepared by ball milling procedure adding Lithium. SIGVIEW software was used for Digital Signal studies. Comparing, the signals obtained by electrochemical techniques and the research by computational tools; it was possible to find out a behavior path of samples. Display devices made by graphene were observed to provide new information about the structure of samples and how nanotechnology area can be improved. The current investigation aimed at maintaining electrochemical stability, since different deformations, as twisting and bending are quite relevant in portable electronics devices.

This contribution reports, to the best of our knowledge, for the first time on the neutron tunneling phenomenon in nickel isotopes based nanostructured. More accurately, 58Ni-62Ni-58Ni thin films Fabry-Perot resonator configuration exhibited several tunneling resonances. In total, there were 7 tunneling resonances. These tunneling resonances manifest themselves via sharp dips in the total reflection plateau due to quasi-bound states in the nanostructured isotopic based nickel thin film Fabry-Perot resonator.