نتایج جستجو برای: metals and alloys
تعداد نتایج: 16851033 فیلتر نتایج به سال:
Platinum group metals (PGMs) serve as highly active catalysts in a variety of heterogeneous chemical processes. Unfortunately, their high activity is accompanied by a high affinity for CO and thus, PGMs are susceptible to poisoning. Alloying PGMs with metals exhibiting lower affinity to CO could be an effective strategy toward preventing such poisoning. In this work, we use density functional t...
The development of materials which contain the noble metals for use in high temperature strain gauges is reviewed, with particular emphasis being placed upon work done by the Institute of Precious Metals, in China. Three alloy systems displaying excellent resistance to oxidation and good overall properties when used in high temperature straingauges, are singled out for examination. These are pl...
In this paper the electrodeposition of nickel on n-Si(111):H substrate, in the presence of sulphuric acid, was studied. Cyclic voltammetry has been used to characterize the electrochemical behavior of the system. The nickel deposits had a flower-like morphology with the sphericalnanostructure nucleus, distributed uniformly on the surfaces of the prepared n-Si(111) substrate.
Abstract Ultrasonic velocity and attenuation measurements are powerful tools to infer information about the microstructure and properties of metals and their alloys. To begin, elastic constants can be measured with precision as high as one part in 10. At this level of precision, changes in elastic constants caused by texture, phase transformations, and various internal friction phenomena can be...
When a liquid is cooled well below its melting temperature at a rate that exceeds the critical cooling rate Rc, the crystalline state is bypassed and a metastable, amorphous glassy state forms instead. Rc (or the corresponding critical casting thickness dc) characterizes the glass-forming ability (GFA) of each material. While silica is an excellent glass-former with small Rc < 10(-2) K/s, pure ...
The accumulative roll bonding (ARB) as a severe plastic deformation (SPD) procedure aimed at enhancing the mechanical properties of metals and alloys. In the present study, a new slab method is proposed for estimating the forming stress field for cold extrusion of metals cross the alumina interlayer powder particles by accumulative roll bonding process. Plastic deformation behavior of the metal...
Equiatomic alloys (e.g. high entropy alloys) have recently attracted considerable interest due to their exceptional properties, which might be closely related to their extreme disorder induced by the chemical complexity. In order to understand the effects of chemical complexity on their fundamental physical properties, a family of (eight) Ni-based, face-center-cubic (FCC), equiatomic alloys, ex...
Computer models of casting processes are becoming useful tools in the foundry industry. These models are used to simulate the heat and fluid flows that control the microstructural development of castings. The accuracy and usefulness of these computer models depend critically upon the availability of reliable thermophysical properties of metallic melts. For instance, the simulation of the solidi...
The corrosion of metals is a destructive process regarding to the basic modern constructional material with a great importance for the nowadays industry and in many cases represents an enormous economic loss. Therefore, it is not a surprise that the research on the corrosion and corrosion protection of metallic materials is developed on a large scale in different directions and a wide range of ...
Previous experiments have shown that tritium is produced in deuterated titanium. To better define the phenomenon a series of tests have been performed using various metals and alloys and different deuterating conditions. Sheets and shavings of titanium, zirconium, hafnium, tantalum, Zircaloy 2 and Ti-Zr 50% alloy have been tested. A statistical analysis of the tritium production shows that sign...
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