Effect of the laser fusion of electrometallized coatings of the Fe-Cr-B-Al system on their corrosion resistance

We studied the effect of laser treatment of electric arc coatings produced of powder wires of the Fe-Cr-B system on the changes in their structure, electrolytic potential, and polarization currents. We additionally introduced aluminum, nickel, and copper to the charge of these coatings. Laser treatment was realized by means of Nd: YAG laser radiation. We have shown that the addition of a small amount of these elements to the coating under study in different ways affects the character of formation, structure, and electrochemical characteristics of the fused layer. In particular, copper and nickel additions increase the fluidity of the coating. The parameters of laser treatment affect strongly the uniformity of the distribution of elements in the fused zone. In the case of alloying with copper, the nonuniformity of their distribution is more pronounced, which can exert a slight negative influence on the corrosion characteristics of the coating. Aluminum addition improves the corrosion resistance of laser-modified coatings. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 6, pp. 106–110, November–December, 2006.     

Evaluation of Al and Some of Its Alloys as Anode Materials vs γ-MnO2 as Cathode Material and Ore Produced γ-MnO2 vs Zn Anode in KOH Solution

In this study electrochemical performance of Al and some of its alloys (Al-Zn, Al-Mg and Al-Mn) anodes vs MnO2 cathode were carried out in alkaline solution. The results show that the Al-Zn alloy anode has the best cell capacity among the other alloys. Cell capacity values go in the order Al-Zn＞Al-Mg＞Al＞Al-Mn. This result is probably related to the nature of passive films formed on the surface of the alloys which examined by scanning electron microscopy (SEM). SEM morphologies of Al and its alloys showed coarse grains of passive films formed on the surface of these anode materials while Al-Mn morphology shows a needle-like structure.Electrolytic manganese dioxide (EMD) produced by electrodepositing on platinum anode from liquor resulting from reduction of low grade pyrolusite ore (β-MnO2) by sulfur slag was characterized as cathode in alkaline Zn-MnO2 batteries. Ore produced sample (EMD1) was performed well in comparison with EMD standard (EMD2) (commercial battery grade electrolytic manganese dioxide, TOSOH-Hellas GH-S). SEM morphology of Zn anode after cell reaction was carried out and showed that Zn anode has fine grains of passive film on its surface.     

Effect of Burnup and Holding Time of Irradiated Nuclear Fuel on the Mass Ratio of Am, Cm, Np, and Fissioning Plutonium

Computed estimates of the mass ratio of Am, Cm, Np, and plutonium for different burnup of VVÉR and RBMK fuel and the post-reactor holding time are presented. The holding time for which this ratio reaches the admissable value 0.32 is determined.     

Influence of Calcium Phosphates on the Morphology and Properties of Polylactide Composites

Materials Science - We developed polylactide composite materials with calcium-containing fillers; in particular, calcium orthophosphate and calcium hydroorthophosphate. It is shown that the degree...     

Modelling of the thermodynamic properties of the water–ammonia mixture by three different approaches

This paper deals with the modelling of the thermodynamic properties of the water–ammonia refrigerant mixture. Three different approaches are formulated and compared. The first is an empirical approach based on a free enthalpy model of the mixture considered as the resultant of the properties of its pure components and of an excess term corresponding to the deviation to the ideal solution concept. Secondly, a semi-empirical approach based on the PATEL and TEJA cubic equation of state is considered. Finally, a theoretical approach formulated as PC-SAFT (perturbed chain statistical associating fluid theory) equation of state is treated. A comparison of these three methods proves the superiority of PC-SAFT in predicting and extrapolating the thermodynamic properties of the water–ammonia system up to very high temperatures and pressures.     

Effect of the chemical structure of hexenyl succinic acid esters – the foundation of synthetic oils – on their dynamic viscosity

The correlation between the dynamic viscosity and chemical structure of hexenyl succinic acid esters is investigated in a wide temperature range from −30 to +10 °C for different rotation frequencies.     

Determination of Se,As, Sb,Te, and Bi in wastewaters of mining-and-processing integrated works with the use of AAS-ETA

The procedure of analysis of wastewaters of mining-and-processing integrated works on the content of Se, As, Sb, Te, and Bi with the use of an atomic absorption method with electrothermal atomizer, which involves the preliminary sample preparation and choice of temperature program, modifier, and corrector of nonselective absorption, was described. The conditions were matched for the determination of low concentrations of these elements in natural waters.