Immiscibility in binary alloys of group IA metals (lithium,sodium and potassium)

This paper evaluates the miscibility syndrome in order to predict the occurrence of miscibility gaps in the binary alloy systems of lithium, sodium, and potassium and compares its predictions with those from the Hildebrand, the Kumar-Hildebrand parameters or the concept of Mott number. It is shown that statistically, the predictions from the miscibility syndrome are most reliable. An attempt is also made to partially rationalize the nature of the binary liquid systems in terms of the electronic configuration of the valency electrons.     

Corrosion behavior of metals and alloys in marine-industrial environment

Abstract

This work deals with atmospheric corrosion to assess the degrading effects of air pollutants on ferrous and non-ferrous metals and alloys, which are mostly used as engineering materials. An exposure study was conducted in the Tuticorin port area located on the east coast of South India, in the Gulf of Mannar with Sri Lanka to the southeast. Common engineering materials, namely mild steel, galvanized iron, Zn, Al, Cu and Cu–Zn alloys (Cu–27Zn, Cu–30Zn and Cu–37Zn), were used in the investigation. The site was chosen where the metals are exposed to marine and industrial atmospheres. Seasonal 1 to 12 month corrosion losses of these metals and alloys were determined by a weight loss method. The weight losses showed strong corrosion of mild steel, galvanized iron, Cu and Zn and minor effect on Al and Cu–Zn alloys. Linear regression analysis was conducted to study the mechanism of corrosion. The composition of corrosion products formed on the metal surfaces was identified by x-ray diffraction and Fourier transform infrared spectroscopy.     

Corrosion behavior of metals and alloys in marine-industrial environment

This work deals with atmospheric corrosion to assess the degrading effects of air pollutants on ferrous and non-ferrous metals and alloys, which are mostly used as engineering materials. An exposure study was conducted in the Tuticorin port area located on the east coast of South India, in the Gulf of Mannar with Sri Lanka to the southeast. Common engineering materials, namely mild steel, galvanized iron, Zn, Al, Cu and Cu–Zn alloys (Cu–27Zn, Cu–30Zn and Cu–37Zn), were used in the investigation. The site was chosen where the metals are exposed to marine and industrial atmospheres. Seasonal 1 to 12 month corrosion losses of these metals and alloys were determined by a weight loss method. The weight losses showed strong corrosion of mild steel, galvanized iron, Cu and Zn and minor effect on Al and Cu–Zn alloys. Linear regression analysis was conducted to study the mechanism of corrosion. The composition of corrosion products formed on the metal surfaces was identified by x-ray diffraction and Fourier transform infrared spectroscopy.     

Thermodynamic properties of liquid metals and alloys

A modified cellular model of liquids is used to develop a method for calculating thermodynamic properties of liquid metals and their alloys, which are widely used in compact modern heat exchange equipment operating at high thermal flux densities. The approach presented herein permits calculation of the properties of metals from various groups by a single consistent technique. Good agreement was found with experimental data for a significant number of liquid metals and their alloys.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 5, pp. 832–840, November, 1990.     

Corrosion susceptibilities of various metals and alloys in synthetic geothermal brines

The corrosion susceptibilities of various pure metals and alloys were investigated in synthetic geothermal fluids. Rates of corrosion of AISI 1010 steel, types 304 and 316 stainless steels, Monel 400 and nickel were determined at three temperatures (296, 333 and 368 K); and those of the molybdenum, niobium and titanium were determined at 368 K only. Type 304 stainless steel appears to undergo an active-passive transition at a temperature range between 333 and 368 K. In the passive state type 304 steel has essentially the same corrosion rate as type 316. At 368 K the corrosion rate of pure nickel was approximately 2.5 times that of Monel, which in turn was twice that of type 316 stainless steel. The corrosion rates of Mo, Nb and Ti were less than one mdd at the highest experimental temperature.     

Effects of thermochemical treatment in molten alkali metals on the mechanical properties of refractory metals and alloys

Conclusion Studies have been made on how borosilicide coatings and individual chemical treatment stages affect the mechanical properties of the substrate metal (unalloyed vanadium and VTsU alloy). The redistribution of interstitial impurities between the liquid and solid metals reduces the plasticity of vanadium and VTsU. The working characteristics can be restored by heat treatment of the coated material, namely high-temperature ageing.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 27, No. 2, pp. 52–57, March–April, 1991.     

Distribution of interstitial impurities in titanium-vanadium alloys after holding in liquid lithium

The distribution of interstitial impurities between liquid lithium and solid titanium-alloyed vanadium is investigated. It is shown that titanium alloying of vandium intensifies nitrogen and carbon transport from lithium into the solid metal. At the same time, the concentration of oxygen in the surface layers of the specimens increases as a result of penetration of lithium and formation of complex oxides of the Me _x Li _y O _z type. Increase in the titanium content leads to an increase in the carbon concentration on the surface and to the formation of protective carbon films that inhibit the diffusion of interstitial impurities into deep-seated layers.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 5, pp. 56–60, September–October, 1993.     

Corrosion behaviour of steels and refractory metals in flowing Lead-Bismuth Eutectic at low oxygen activity

The corrosion behaviours of AISI 316L and T91 steels, and several refractory metals as W, Mo and Ta, were investigated in flowing lead-bismuth eutectic (LBE) at 400°C. The tests were performed in the LECOR (Lead Corrosion) loop, at low oxygen activity in LBE. The results obtained show that all materials exhibited a weight loss after exposure to the flowing LBE, except for the case of tantalum, which exhibits a weight gain. The resistance to corrosion offered by refractory metals has been found higher in comparison to the case of both steels. Moreover, the austenitic steel behaved more resistance to corrosion induced by LBE than the martensitic steel, under the test condition adopted.