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In recent years, Thermochemical Heat Storage (THS) systems and storage materials are important for the development of these systems have attracted a great interest. In this study, composite materials were prepared by impregnating sorbent salts (MgCl2, LiNO3) into vermiculite (V). The cyclical heat storage behaviors of the obtained composite structures were investigated with the laboratory scale thermochemical heat exchanger prototype system. Accordingly, the stability of the V+MgCl2 composite during repeated cycles and the energy storage density (Ed) value calculated as a result of the measurements in the prototype were found to be higher than the V+LiNO3 composite, as in the DSC analysis results. [ABSTRACT FROM AUTHOR]

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In this study, the effect of artificial aging on hardness and the corrosion properties of 6063 Al alloy was investigated. Time and temperature play a very important role in the precipitation hardening process of the Alalloy. The results show that the variation in time and temperature have changed the hardness of aluminum alloy. Corrosion test revealed that the corrosion resistance of the alloy strongly depended on artificial aging times. The highest corrosion resistance for all artificial aging temperatures was observed at obtained the highest hardness value. [ABSTRACT FROM AUTHOR]

Our previous article (Özkan, Philos. Mag. 2014) described a practical method to determine temperature dependence of the bulk modulus by using pressure dependence of the bulk modulus and the related analytical equations. The present study extended the method at low temperatures to obtain the bulk modulus of the superconducting peroxide MgCNi3, below room temperature. The bulk modulus of MgCNi3, decreases with temperature at a rate less than -0.008 GPa/K below 100K, then it decreases at a higher rate, -0.020GPa/K near 300 K, being close to corresponding theoretical values for the other non-oxide perovskites. Moreover, the Gruneisen parameter of MgCNi3, decreases from 300 K to 120 K, goes through a minimum and increases at lower temperatures. The thermal pressure, otvKT gradually increases from 1.1 MPa/K at 40 K to 2.0 at 100K then, increases with slightly reduced rate to 4.9 MPa/K at 300 K being in reasonable agreement with the related data in the literature. This study verifies that the outlined method may be used to predict bulk moduli data below room temperature to substantiate the related studies. [ABSTRACT FROM AUTHOR]

Mixed-phase TiO2 nanocomposite thin films consisting of anatase and rutile prepared on commercially pure Ti sheets via the electrochemical anodization and annealing treatments were investigated in terms of their photocatalytic activity for antibacterial use around dental implants. The resulting films were characterized by scanning electron microscopy (SEM), and X-ray diffraction (XRD). The topology was assessed by White Light Optical Profiling (WLOP) in the Vertical Scanning Interferometer (VSI) mode. Representative height descriptive parameters of roughness Rα and Rz were calculated. The photocatalytic activity of the resulting TiO2 films was evaluated by the photodegradation of Rhodamine B (RhB) dye solution. The antibacterial ability of the photocatalyst was examined by Aggregatibacter actinomycetemcomitans suspensions in a colony-forming assay. XRD showed that anatase/rutile mixed-phase TiO2 thin films were predominantly in anatase and rutile that were 54.6 wt% and 41.9 wt%, respectively. Craters (2-5 µm) and protruding hills (10-50 µm) on Ti substrates were produced after electrochemical anodization with higher Rα and Rz surface roughness values. Anatase/rutile mixed-phase TiO2 thin films showed 26% photocatalytic decolorization toward RhB dye solution. The number of colonizing bacteria on anatase/rutile mixed-phase TiO2 thin films was decreased significantly in vitro. The photocatalyst was effective against A. actinomycetemcomitans colonization. [ABSTRACT FROM AUTHOR]

The Ni-B-Mo coating on steel by electroless plating and the evaluation of the morphology and corrosion performance after applying heat treatments at different temperatures for 1 h were investigated in this study. The 25-μm-thick coating was uniform and adhesion between the substrate and the coating was good. The coating consisted of an amorphous-like structure in their as-plated condition, and after annealing at 400 °C for 1 h, crystallized nickel, nickel borides, and molybdenum carbide were formed. Immersion tests in 10% HCl solution and potentiodynamic polarization measurements in 3.5% NaCl aqueous solution were applied to investigate corrosion resistance. The corrosion performance of heat-treated coatings was compared with steel and the as-plated coating. By increasing the annealing temperature, corrosion potential shifted toward a noble direction, corrosion current density decreased and the weight loss of specimens decreased, demonstrating an increase in corrosion resistance. Best corrosion performance was achieved by the coating heat treated at 550 °C . [ABSTRACT FROM AUTHOR]

Electrodeposition, also known as electroplating, refers to the process where a thin film of metal is deposited onto a conductive substrate under an applied current. The electrodeposition of alloys on a substrate requires the simultaneous deposition of two or more metals. Electrodeposition is both a costeffective and simple method to produce thin film materials (such as NiFe, CoNi, CoFe and NiCoFe). Nickel, cobalt and iron, ( iron-group metals), and their alloys are important engineering materials in many applications because of their unique magnetic, corrosion and wear-resistance, thermophysical and electrocatalytic properties. For example, NiFe and NiCoFe alloys are strong candidates for application in high density magnetic recording heads due to their high saturation flux density and low coercivity. These functional materials are usually prepared by electroplating because this technique is often much cheaper and simpler than other methods. In addition, advantages of electrodeposition include low deposition temperature and the simplicity of the required apparatus. The magnetic properties of these materials are seriously affected by their composition and structure thus, reliable control of these properties for the iron-group alloys is important for their wide applications. The standard equilibrium potentials of Ni, Co, and Fe are -0.25, -0.27, and -0.44 V vs. the normal hydrogen electrode (NHE), respectively. Therefore from a thermodynamic consideration Ni is the most noble of the three metals. On the basis of these values, in normal codeposition, nickel is expected to electroplate preferentially to cobalt and cobalt preferentially to iron. When these metals are plated individually, the kinetics of the electrodeposition of individual metals follows the trend expected from the standard equilibrium potential. However, when Fe is present in the same solution with either Ni, Co or both ions, there is often potential range where the rate of Fe deposition exceeds the rate of Ni and Co deposition occurs. The called anomalous codeposition of iron group metals is characterized by the less noble metal deposition preferentially to the nobler one. In other words, the reduction of nickel is inhibited while the deposition of iron and/or cobalt are enhanced when compared with their individual deposition rates. The study on the anomalous deposition of the irongroup alloys can be traced back to 1927. The mechanism of anomalous codeposition of iron group metals has been studied by many researchers and several hypotheses have been presented in the literature. … [ABSTRACT FROM AUTHOR]