Impact of micro-indentation load/time and Zinc concentration on the thermo-mechanical characteristics of amorphous Se78_{78}Te20_{20}Sn2_2 alloy

We have performed hardness measurement experiments under different loads and loading times by performing micro-indentation marks in the present work. Chalcogenide glasses (ChGs) comprising Se$_{78}$Te$_{20}$Sn$_2$ and Se$_{78-x}$Te$_{20}$Sn$_2$Zn$_x$ (where $x = 0, 2, 4, 6$) alloys are the subject of micro-indentation tests in this work. We have utilized both micro-indentation and optical microscopic methods to determine Vickers hardness. Thermal glass transition phenomena have been identified through DSC techniques. The modulus of elasticity (E), an essential mechanical property, has been evaluated using established empirical equations. Further, we have studied other mechanical parameters [e.g., minimal micro-void formation energy (Eh), glass's fragility index (m), micro-void volume (Vh), etc.] and the covalent character of the glassy system. Additionally, various physical parameters, including density, molar volume, and compactness, have also been determined

Effect of Nano-Silica on The Thermo-Physical Properties of the Thermal Eutectic (Na0.6K0.4)NO3 System

Here, we investigate the effect of adding nano-silica particles on the thermo-physical properties of the (Na0.6K0.4)NO3 based thermal energy storage systems. Five different systems tagged as M00, M01, M02, M03 and M04, with different nano-silica percentage of 0, 1, 2, 3, and 4 wt%, respectively, were prepared. Various experimental techniques were employed to study the thermo-physical properties of the systems during (solid-solid) phase P1, (solid-liquid) phase P2 and (liquid-solid) phase P3, and to clarify the effect of nano-silica on the thermal energy storage efficiency during both charging and discharging processes. According to the Differential Scanning Calorimeter (DSC) thermal analysis, it was found that the system M02 whose nano-silica addition rate of 2 wt%, has the most favorable thermal characteristics (i.e., highest specific heat and lowest enthalpy change). Moreover, the addition of 2 wt% represents the optimum distribution of nano-silica inside the principal base system M00. This leads to an improvement in the porosity of the system due to the degree of homogeneity caused by the thermophoresis effect distribution, the high surface area of the nano-silica with the activity of the M00 matrix alongside the degree of the alkalinity of nano-silica. Besides, the electric conductivity measurements showed that the 2wt% percentage is the optimum one for thermal energy storage systems

Solution-processed nanostructured ZnO/CuO composite films and improvement its physical properties by lustrous transition metal silver doping

This paper has reported the fabrication and characterization of pristine, and silver (Ag)-doped nanostructured ZnO/CuO composite thin films that have not been previously reported. The thin films were synthesized by the successive ionic layer adsorption and reaction (SILAR) technique. The morphological, crystalline structure, optical and electrical characterizations of the films have been achieved utilizing scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), atomic force microscopy (AFM), X-ray diffraction (XRD) analysis, Fourier transform infrared spectrum (FTIR) analysis, ultraviolet-visible (UV-Vis) spectrophotometry and the four-point probe measurements. Particle sizes of pristine and Ag-doped ZnO/CuO thin films were found to vary from 32 to 58 nm. Crystallite size was changed from 16.40 to 18.90 nm with changing Ag dopant in the ZnO/CuO composite film. FTIR spectra that have the absorption peaks at similar to 725 and similar to 510 cm(-1) referred to the stretching vibration of Zn-O and Cu-O bonds during the synthesis of ZnO/CuO nanofilms. The bandgap values of ZnO/CuO composite films increased from 2.05 to 2.36 eV as Ag content increased from 0 to 2 M%. The activation energies of the samples were obtained from the Arrhenius plots of sigma versus 1/T. The multiple activation process was observed. It was noteworthy that Ag-doping results in a significant difference in conductivity at all temperature values