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The focus of this study is the evaluation of the influence of Ti concentration on the tensile properties of powder metallurgy high entropy alloys. Three Ni1.5Co1.5CrFeTiX alloys with X = 0.3; 0.5 and 0.7 were produced by mechanical alloying and spark plasma sintering. Additional annealing heat treatment at 1100 °C was utilized to obtain homogenous single-phase face centered cubic (FCC) microstructures, with minor oxide inclusions. The results show that Ti increases the strength of the alloys by increasing the average atomic size misfit i.e., solid solution strengthening. An excellent combination of mechanical properties can be obtained by the proposed method. For instance, annealed Ni1,5Co1,5CrFeTi0.7 alloy possessed the ultimate tensile strength as high as ~1600 MPa at a tensile ductility of ~9%, despite the oxide contamination. The presented results may serve as a guideline for future alloy design of novel, inclusion-tolerant materials for sustainable metallurgy

The focus of this study is the evaluation of the influence of Ti concentration on the tensile properties of powder metallurgy high entropy alloys. Three Ni1.5Co1.5CrFeTiX alloys with X = 0.3; 0.5 and 0.7 were produced by mechanical alloying and spark plasma sintering. Additional annealing heat treatment at 1100 °C was utilized to obtain homogenous single-phase face centered cubic (FCC) microstructures, with minor oxide inclusions. The results show that Ti increases the strength of the alloys by increasing the average atomic size misfit i.e., solid solution strengthening. An excellent combination of mechanical properties can be obtained by the proposed method. For instance, annealed Ni1,5Co1,5CrFeTi0.7 alloy possessed the ultimate tensile strength as high as ~1600 MPa at a tensile ductility of ~9%, despite the oxide contamination. The presented results may serve as a guideline for future alloy design of novel, inclusion-tolerant materials for sustainable metallurgy

The focus of this study is the evaluation of the influence of Ti concentration on the tensile properties of powder metallurgy high entropy alloys. Three Ni1.5Co1.5CrFeTiX alloys with X = 0.3; 0.5 and 0.7 were produced by mechanical alloying and spark plasma sintering. Additional annealing heat treatment at 1100 °C was utilized to obtain homogenous single-phase face centered cubic (FCC) microstructures, with minor oxide inclusions. The results show that Ti increases the strength of the alloys by increasing the average atomic size misfit i.e., solid solution strengthening. An excellent combination of mechanical properties can be obtained by the proposed method. For instance, annealed Ni1,5Co1,5CrFeTi0.7 alloy possessed the ultimate tensile strength as high as ~1600 MPa at a tensile ductility of ~9%, despite the oxide contamination. The presented results may serve as a guideline for future alloy design of novel, inclusion-tolerant materials for sustainable metallurgy

In situ infrared reflection spectroscopy has been used to probe the concentration change of the perchlorate anion in the electrical double layer at Au(100). The results obtained show clearly that there is a correlation between the integrated intensity of the perchlorate band determined in a (SNIFTIRS) experiment and the surface excess of the anion in the diffuse layer predicted by the Gouy-Chapman theory. An expression that correlates the above two quantities is derived.

The electrosorption valency for the adsorption of parabonic acid has been determined on single crystal gold electrodes and mercury near the point of zero charge. A new technique to perform the measurement using cyclic voltammetry is described. The electrosorption valency was found to be a linear function both of the potential of zero charge and of the work function of the metal. (AN)

The mechanism of cysteine, cysteinesulfinic acid and cysteic acid electrooxidation in perchloric acid solutions has been studied using cyclic voltammetry. All compounds investigated have been found to be chemisorbed on a polycrystalline gold electrode and oxidized with four, two or one electron, respectively. The water molecule co-adsorbed with cysteine participates in the latter's one-electron oxidation with a lower energy requirement whereas at the completely covered electrode surface, bulk water is involved in multiple electron transfer reactions. A strong inhibiting effect of chloride anions on cysteine oxidation has been observed at the partially covered electrode surface. The effect of adsorbate surface coverage on the reaction mechanism in anodically catalyzed reactions involving oxygen transfer is discussed.

Capacity against potential data for the adsorption of cysteine and other organosulfur compounds on polycrystalline gold are reported. Cysteine, N- acetylcysteamine and cysteinesulfinic acid form monolayers on gold through the thiol group, and significantly lower the interfacial capacity in the double layer region. On the other hand, cysteic acid forms multilayers under the same conditions. The surface excess of the compounds at full monolayer coverage has been estimated, and compared with the data for the adsorption of simple n- alkylthiols. It is argued that the packing of the cysteine and related compounds is more compact due to strong electrostatic interactions.

A detailed examination of the dependence of the a.c. admittance of a cell containing a polycrystalline gold electrode has been made in the double layer region as a function of d.c. potential, a.c. frequency and electrode history. It is shown that the interfacial impedance of a gold electrode with a carefully prepared surface can be treated under these circumstances as a constant phase element when it is in contact with an aqueous solution containing 0.05 M KClO4. Analysis of the frequency dependence of the cell impedance gives the surface inhomogeneity parameter n which tums out to be very close to unity. Although the electrode surface is only slightly inhomogeneous on a microscopic scale, a very large frequency dispersion of the impedance is observed experimentally. A method of estimating the true specific capacity of the electrode is presented, and conditions for carrying out the experiments in a reproducible manner discussed. double layer at gold/solution interface, a.c. admittance techniques, constant phase element model.