Alloying Additions (alloying + addition)

Distribution by Scientific Domains


Selected Abstracts


The wet corrosion of molybdenum thin film , Part II: Behavior at 85°C

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 9 2004
C. R. Tomachuk
Abstract In the past few years there has been increased interest in molybdenum thin films, which are commonly prepared by magnetron sputtering. There is a variety of novel applications of molybdenum such as, for example, components for soft X-ray optics based on Mo/Si multi-layers, the back contact in thin film solar cells, NO gas detection, and microelectronics. Molybdenum is, also, widely used as an alloying addition in stainless steels to facilitate the formation of the passive film and to improve resistance to pitting attack. Its corrosion behaviour is complex and many aspects still need to be clarified. During this study, the corrosion behaviour of the PVD-Mo thin film immersed in aerated sulfate and chloride solutions at 85°C was investigated with both polarization and electrochemical impedance spectroscopy (EIS) measurements. It is apparent that the Mo thin film exhibits increased susceptibility to corrosion in more alkaline environments. [source]


The effect of alloying elements on the crystallization behaviour and on the properties of galvanized coatings

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 1 2004
G. Vourlias
Abstract The influence of the alloying elements on the interface reactions of zinc coatings during the galvanization process was examined. These reactions affect the crystallization and the structure and properties of the outer layer of the coatings. Depending on the type and concentration of the alloying additions in the galvanizing bath differences were induced in the crystallization process of the Fe-Zn phases. It was found that both the concentration and the distribution of the alloying elements played an important role in the growth of the phases. The formation of the phases and the distribution of the alloying elements in the coatings were determined using X-Ray diffraction (XRD) and Scanning Electron Microscopy (SEM) associated with an Energy Dispersive X-Ray Spectroscopy (EDS) analysis. Finally the behaviour of the galvanized coatings was examined under accelerated salt spray corrosion conditions. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Chemical composition of new copper alloys for machining and its effect on their susceptibility to corrosion cracking

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 9 2007
B. Eremiá
Zinc-containing copper alloys, the so-called ,,+,, brasses, are commonly used in contact with potable water. These materials are alloyed with lead to improve machinability. In wrought special brass alloys, reducing the content of this alloying element or replacing it with alternative alloying additions may give rise to a new type of machinable copper alloys which differ from the original alloys by their contents of other modifier elements such as Si (or possibly, Mg, Bi, and P). These alloys have a very low content of lead required for the break-up of chips during machining. Even though these types of brass exhibit a very good machinability, the effects of their chemical composition on the resistance of the alloy to corrosion cracking have not yet been given sufficient attention. This paper aims to present an assessment of three new types of machinable copper alloys regarding their susceptibility to stress corrosion cracking, in comparison to that of the lead-alloyed variety, in 0.05 M NaCl, NaNO2, and Na2SO4 solutions. The slow strain rate test has been used for this purpose, and its results were correlated with metallographic evaluation of the number and depth of the cracks observed on the test specimen surfaces on completion of the test. [source]


Effects of minor additions and impurities on oxidation behaviour of FeCrAl alloys.

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 12 2005
Development of novel surface coatings compositions
Abstract In the present work the effects of single or combined minor additions of Zr, Hf, Ti and C on the oxidation behaviour of Y-containing, FeCrAl alloys have been studied. For this purpose high-purity, model alloys with single or multiple minor alloying additions were used. The results of long term discontinuous oxidation tests and detailed kinetics studies using thermogravimetry were complemented with extensive microstructural characterisation of the formed alumina scales using SEM and STEM. Hence, the oxidation kinetics and scale spallation rates and failure modes were correlated with the oxide composition and microstructure. The results demonstrate that the frequently reported positive effect of Zr, Hf and Ti on the lifetime oxidation behaviour of FeCrAl alloys can only be fully exploited if the concentrations of the above elements are carefully adjusted and the interaction with typical alloy impurities, such as carbon, is considered. [source]


Magnetic properties of Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003
A. Chrobak
Abstract The paper contains experimental results referring to optimization of soft magnetic properties and crystallization in the Fe76X2B22 (X=Cr,Zr,Nb) amorphous alloys. We have used measurement of thermomagnetic balance, magnetic permeability, coercive field and also HREM and X-ray diffraction techniques. It was shown that Zr and Nb alloying additions cause a slowing down of diffusion processes and an increase of the annealing for 1 hour optimization temperature of about 50 and 100 K, respectively. Activation enthalpies of the crystallization process were determined as: 2.0 eV (X=Cr), 2.6 eV (X=Zr) and 4.4 eV (X=Nb). [source]