Alloy experimental studies

The above results demonstrate that computational screening is promising technique for use in electrocatalyst searches. The screening procedure can be viewed as a general, systematic, DFT-based method of incorporating both activity and stability criteria into the search for new metal alloy electrocatalysts. By suggesting plausible candidates for further experimental study, the method can, ultimately, result in faster and less expensive discovery of new catalysts for electrochemical processes. 

General data on fire hazards present in industrial oxygen-producing plants are given with details of experimental study of factors involved in combustion of various metals and alloys used in such plant. Safety in selection of materials is discussed [1]. A study of combustion of structural metals (Fe, Al) in oxygen is given [2], See Oxygen (Liquid) Metals... 

Experimental studies have shown that in many alloy systems the number of valence electrons is the dominant factor. Electron density is usually taken to denote the... 

It should be noted that it is difficult to obtain models that can accurately predict thermal contact resistance and rapid solidification parameters, in addition to the difficulties in obtaining thermophysical properties of liquid metals/alloys, especially refractory metals/al-loys. These make the precise numerical modeling of flattening processes of molten metal droplets extremely difficult. Therefore, experimental studies are required. However, the scaling of the experimental results for millimeter-sized droplets to micrometer-sized droplets under rapid solidification conditions seems to be questionable if not impossible,13901 while experimental studies of micrometer-sized droplets under rapid solidification conditions are very difficult, and only inconclusive, sparse and scattered data are available. 

These sort of problems make it difficult to obtain reliable high temperature data on the aqueous chemistry of transition metal ions. Unfortunately the necessary timescales for even the simpler experimental studies are frequently too long for a Ph.D. student to make reasonable progress in 3 years from scratch or for industrial researchers to make much reportable progress before the patience of those supporting the work is exhausted. Results can be reported far more rapidly from, for example, corrosion experiments and since corrosion theories are in general of so little predictive value, each relevant alloy/electrolyte combination needs its own study. In such circumstances it is hardly surprising that thermodynamic studies have been (with a few notable exceptions) relatively poorly supported, while corrosion data continue to be amassed without any reliable thermodynamic framework within which to understand them. 

Abrupt changes in the concentration of segregating solute were first observed in experimental studies of carbon segregation in interstitial metal-carbon alloys by Hamilton and Blakely . More recently, such transitions have also been observed in substitutional Cu-... 

Sunderman FW Jr. 1989a. Carcinogenicity of metal alloys in orthopedic prostheses Clinical and experimental studies. Fundam Appl Toxicol 13 205-216. 

Pt alloy monolayer catalysts exhibited even more active ORR behavior compared to Pt monolayer catalysts. To understand this phenomenon computational DFT studies were carried out. The hypothesis to be tested was that, for instance, Ru metal atoms in the Pt—Ru monolayer are OH-covered and could inhibit the adsorption of additional OH on neighboring surface sites (adsorbate-adsorbate repulsion effect). A very similar hypothesis was put forward about three years earlier by Paulus et al. [105] who postulated that Co surface atoms might exhibit a so-called common-ion effect, that is, they could repel like species from neighboring sites. A combined computational-experimental study finally confirmed this hypothesis [123] If oxophilic atoms such as Ru or Os were incorporated into the Pt monolayer catalysts, the formation of adjacent surface OH was delayed, if not inhibited. Oxo-phobic atoms, such as Au, displayed the opposite effect, would not inhibit Pt—OH formation, and were found to be detrimental to the overall ORR activity. 

The solution for a diffusion couple in which two semi-infinite ternary alloys are bonded initially at a planar interface is worked out in Exercise 6.1 by the same basic method. Because each component has step-function initial conditions, the solution is a sum of error-function solutions (see Section 4.2.2). Such diffusion couples are used widely in experimental studies of ternary diffusion. In Fig. 6.2 the diffusion profiles of Ni and Co are shown for a ternary diffusion couple fabricated by bonding together two Fe-Ni-Co alloys of differing compositions. The Ni, which was initially uniform throughout the couple, develops transient concentration gradients. This example of uphill diffusion results from interactions with the other components in the alloy. Coupling of the concentration profiles during diffusion in this ternary case illustrates the complexities that are present in multicomponent diffusion but absent from the binary case. 

Kojo T, Kaneko T, Ito A, et al. 1986. [Experimental studies of the effect of metal cores (silver alloy) on the gingival tissue. 2nd report. Extensive investigation of gingival discoloration], J Jpn Prosthoclort Soc 30 1278-1286. (Japanese). 

Tsui, T.Y., Oliver, W.C. and Pharr, G.M. (1996), Influence of stress on the measurement of mechanical properties using nanoindentation Part I. Experimental studies in an aluminium alloy , Journal of Materials Research, 11, 752-759. 

POSTER TITLE Thermodynamic and Experimental Study on P Removal from Si-based Alloy for Solar Grade Silicon Refining... 

Unfortunately, there are no specific experimental studies of spreading kinetics of alloy/oxide systems in which only adsorption occurs without formation of a 3D compound. However, when analysing R(t) curves in reactive systems, it may be useful to calculate the spreading rate in the case where the decrease of the contact angle is due to the lateral extension of an adsorption layer. This needs diffusion of interface-active solute from the drop bulk to the liquid adjacent to the adsorption layer at the triple line, followed by a transfer from the liquid to the adsorption... 

It is possible experimentally to trace out the curves for a single structure for intermediate concentrations of electrons by making alloys. A study, for example, of body-centered cubic alloys by Cheng, Gupta, van Rcuth, and Beck (1962) showed a sharp peak at concentrations between six and seven electrons per atom. This peak is presumably associated with the highest-energy peak in the body-centered cubic density of states. Fig. 20-7. 

In the last few decades, a considerable number of experimental studies have been carried out to determine partitioning of the candidate light elements between core and mantle at relevant pressures, temperatures, compositions, and redox conditions. The effects of light elements on the wetting behavior of liquid iron-alloy with respect... 

Only a few systematic studies have been made of the effect of fluid flow on the ECP of power plant alloys in high-temperature water, even though theory suggests that the effect should be substantial under certain conditions [43]. Because the theoretical predictions, from the mixed-potential model (MPM) [43] and more recently the advanced mixed-potential model (AMPM) [47], preceded systematic experimental studies, it is appropriate to discuss the theoretical predictions first. 

Experimental studies of the effect of flow rate on the ECP of Types 304SS and Alloy 182 in high-temperature water have been reported by Macdonald et al. [51], on Type 316SS under simulated BWR chemistry conditions by Kim et al. [52, 53], and on Type 304SS by Prein and Molander [54]. In the work of Macdonald et al. [51] tubular flow at low flow rates was employed which, while not simulating the exact conditions in BWR coolant circuits did provide a sensitive test of the MPM. A comparison between experiment and theory is shown in Fig. 21. The experimental... 

Ngygen, T.G., D. Favier, and M. Suery, Theoretical and Experimental Study of the Isothermal Mechanical Behavior of Alloys in the Semi-Solid State, International J. Plasticity 10 663-693 (1994). 

Recently, nucleation and growth processes taking place in the initial stages of electrodeposition of alloys were studied theoretically and experimentally by Milchev and Lacmann [6.141-6.143]. 

Theoretical and experimental studies of surface segregation equilibrium phenomena in metallic alloys have been focused traditionally on substitutional solid solutions with elemental constituents (and non-metal impurities) assumed to be randomly distributed among the crystal lattice bulk and surface sites. Only in recent years more attention have been paid to the role of compositional order in surface segregation [1]. 

In the following section we will discuss a number of experimental studies that have been designed to examine the findings presented above, which suggested that the Sn/Ni surface alloy should exhibit improved carbon tolerance compared to the monometallic Ni catalyst. 

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