Effect of aluminum on tne stbility of the ß-phase in ß-titanium alloys

At present the development of ß-titanium alloys has reached a new stage. Attempts over many years (since the end of the 1950s) to develop a universal industrial ß-titanium alloy have not been successful. At present, the use of ß-alloys is limited, although a great number of alloying systems have been tried. The creation of new ß-alloys requires an analysis of the data obtained. Investigators have come to a common opinion by analyzing the effect of ß-stabilizers and neutral strengthening elements on the properties and structure of ß-titanium alloys. This cannot be said about the effect of aluminum. Many investigators believe that the aluminum content in ß-titanium alloys should not exceed 3%. However, this has not been appropriately substantiated. This work concerns the effect of aluminum content on the stability of the ß-phase and presents some concepts on alloying ß-titanium alloys.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 9, pp. 3–35, September, 1995.     

Untersuchungen Zur Inhibition Der Lochfraßkorrosion Von Nickel Und Stahl Mit Benzyl-n-propylsulfid

Measurements of pitting potentials of nickel single crystals and stainless steel in solutions with different concentrations of NaCl, pH 2–7, in the presence and absence of benzyl-n-propylsulphide (BPS) by potentiostatic polarisation measurements are described.Amperostatic polarisation curves in the cathodic and anodic active range have been measured in 0·5 m NaCl.The decomposition of BPS was studied by use of iodometrical measurements of SH-groups. The adsorption of BPS³⁵ has been investigated with the aid of tracer techniques.The results show an inhibiting effect on pitting corrosion at conditions allowing the formation of SH^? and BPSH⁺-ions, indicating secondary processes to play the most important role in inhibiting mechanism. Additions of Na₂S lead to increasing efficiency.     

Elektrochemische Rauschmessungen – Innovation in der Korrosionsprüfung

Electrochemical noise measurements – Innovation in corrosion testing There are a lot of approved and standardized methods available for corrosion testing which have found wide application. Salt-spray testing, electrochemical polarization techniques and exposure tests in specific test media belong to these. Nevertheless, some questions remain unanswered and requirements unsatisfied. In particular, both the start of corrosion and the way it proceeds with time can often be examined only to an insufficient extent. Furthermore, the requirements of practical test conditions, acceptable effort and expenditure and shorter test durations lead to continuous development of these test methods. Within corrosion research, the analysis of electrochemical noise offers a simple, sensitive and virtually non-destructive measuring technique for assessment of the corrosion susceptibility of metallic materials and for the investigation of corrosion processes. The present status of knowledge concerning noise diagnostics in corrosion processes permits the application of this method not only to experimental tasks in the laboratory, but also to special problems in the context of practical corrosion monitoring. Furthermore, specific advantages of the technique enable its use to an increasing extent in supporting or improving conventional corrosion testing. The advantages here include obtaining additional information and shortening testing times (together with associated savings in resources such as manpower, energy, chemical reagents, etc.), thus resulting in state-of-the art corrosion testing.     

Der Einfluβ Der Spezifischen Adsorption Von Halogenidionen Auf das Elektrochemische Verhalten der Nickel-Elektrode

Small additions of the halide ions (F^?, Cl^?, Br^?, I^?) to 1N H₂SO₄ result in marked deviations of the current density/potential curves as well as the capacitance/potential curves from nickel, compared with those obtained in pure H₂SO₄. The different actions are explained by the varying tendency of the halide ions to specific adsorption at the nickel surface.The time-dependence of the capacitance demonstrates the existence of a two-stage process for the adsorption of iodide ions.In the presence of iodide ions the influence of their concentration was measured with respect to current density and capacitance.     

Effects of combination modes of favorable growth unit of Al（OH）3 crystals precipitating on Van der Waals and chemical bond force

The dipole moment, total energy, atomic charge, orbital population and orbital energy of four representative combination models of the favorable growth unit Al6（OH）18 （H2O）6 of Al（OH）3 crystals precipitating are calculated by ab initio at RHF/STO-3G, RHF/3-21G, RHF/6-31G levels and DFT at RB3LYP/STO-3G, RB3LYP/ 3-21G, RB3LYP/6-31G levels with Dipole ＆ Sphere solvent model. The effect of various combination models on Van der Waals force is analyzed using dipole moment and molecular radius, and that on chemical bond force is analyzed using total energy, orbital population and orbital energy.     

X-ray evidence for structural changes in the organic conductors, α-(BEDT-TTF)2I3, α-(BEDT-TTF)2IBr2 and ß-(BEDT-TTF)2I3

Interrelations are investigated between the electrical and structural properties of organic conductors, BEDT-TTF (bis(ethylenedithiolo)tetrathiafulvalene) trihalides. In α-)BEDT-TTF)₂I₃ evidence is obtained by X-ray diffraction for BEDT-TTF molecular dimerization at the metal-insulator transition temperature of 135 K. Another BEDT-TTF molecular dimerization is found in α-(BEDT-TTF)₂IBr₂, which has semiconducting properties and an activation energy that increases with decreasing temperature. These dimerizations are considered to be responsible for the changes in the electrical properties. Superconducting ß-(BEDT-TTF)₂I₃ is found to have a superstructure below 175 K, above which short-range fluctuations are observed up to about 200 K.