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Pack Aluminizing of Copper

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Journal of Materials Science & Technology 1997年第2期13卷 127-132页

作者： M.E.Abd El-Azim H.M.Soliman (Metallurgy Dept., atomic energy authority cairo, Egypt) Metallurgy Dept. Atomic Energy Authority Cairo Egypt

Aluminizing of Cu by a pack cementation process was performed to improve its surface *** effect of variation of pack aluminizing temperature from 800 to 900℃ and aluminizing time from 1 to 6 h on the microstructure and the thickness of the aluminide coating of Cu was investigated. Pack aluminizing of Cu significantly improved the microhardness and the oxidation resistance. The microhardness was increased about seven times and the oxidation resistance,after 96 h exposure in air at 900℃, was extremely increased ten times by aluminizing Cu at 900℃ for 3 h.

关键词： VHN Pack Aluminizing of Copper

Performance of the Aluminide Coating of SomeLow Alloy Steels

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Journal of Materials Science & Technology 1997年第6期13卷 462-466页

作者： H.M.Soliman and M.E.Abd E1-Azim(Metallurgy Dept., atomic energy authority, cairo, Egypt ) Metallurgy Dept. Atomic Energy Authority Cairo Egypt

Two low alloy steels 0.5Cr-0.5Mo-0.25V and H85 were pack-aluminized at 900°for 4 h by using Fe-Al powder mixture containing 48% Fe, 20.6% Al- 29.4% Al2O3 and 2% NH4Cl by weight. The microhardness and oxidation resistance at 900℃ of the aluminide coatings were studied. It was found that pack-aluminizing improves the microhardness of the 0.5Cro.5Mo-0.25V steel while it reduces the microhardness of the H85 steel. Pack aluminizing highly improves the oxidation resistance after 20h exposure at 900℃ in air for the investigated steels.

关键词： Cr Performance of the Aluminide Coating of SomeLow Alloy Steels

Characterization of Failure Mechanisms of Duplex and Graded Thermal Barrier Coatings Exposed to Thermal Shock Test

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Journal of Materials Science & Technology 1996年第1期12卷 35-40页

作者： A.F.Waheed and H.M.Soliman(Dept. of Metallurgy, Nuclear Research Center, atomic energy authority, cairo, Egypt) Dept. of Metallurgy Nuclear Research Center Atomic Energy Authority Cairo Egypt

The beginning of failure of a (ZrO2-7%Y2O3)/(Ni-22%Co-17%Cr-12.5%Al-0.6%Y) duplex andgraded coating systems on lnconel 617 and IN738LC in burner rig tests has been *** test conditions are 40 s heating up to 75O℃ substrate temperature followed by 80 s aircooling. Failure is considered at the appearance of the first bright spot during heating *** due to thermal expansion mismatch strains on cooling are the probable cause of life-limiting in this conditions of testing.

关键词： Co Miller Characterization of Failure Mechanisms of Duplex and Graded Thermal Barrier Coatings Exposed to Thermal Shock Test

Effect of Molybdate Ions on the Corrosion Behaviour of Ti Alloys

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Journal of Materials Science & Technology 2000年第1期16卷 45-49页

作者： Magda.M.A.Gad, Kamal.E.Mohamed and Abdelwahab A.El-Sayed (Metallurgy Dept., Materials Division, atomic energy authority, cairo, Egypt) Metallurgy Dept. Materials Division Atomic Energy Authority Cairo Egypt

Titanium alloys are extensively used in power, chemical and petroleum industries as constructional materials for vessels and heat transfer tubes. Moreover they are candidate materials for nuclear waste disposal. These alloys have superior resistance to localized forms of corrosion compared to stainless steels and Ni-base alloys. However, this resistance is not as remarkable in crevice corrosion conditions in some aggressive media. Electrochemical corrosion tests were conducted on two ASTM Ti grades namely, Ti-2 and Ti-12 in extremely low pH acidic environment. Results indicated that Ti-2 has less resistance to both general and crevice corrosion attack than Ti-12. Both alloys possess better resistance to general corrosion than to crevice corrosion. Also, results showed that the molybdate addition improves remarkably the resistance of Ti-2 to both types of attack. The increase of molybdate ions concentration from 0.03 mol/L to 0.15 mol/L made Ti-2 to be as resistant as, or somewhat higher than, Ti-12. The elecrochemical findings were further supplemented by optical examination of the corroded surface.

关键词： Ti Mo Effect of Molybdate Ions on the Corrosion Behaviour of Ti Alloys

Cadmium status in Egypt

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Journal of Environmental Sciences 2001年第3期13卷 351-360页

作者： M. F. Abdel Sabour (Soil & Water Pollution Unit, Nuclear Research Center, atomic energy authority, cairo, Egypt 13759. Soil &Water Pollution Unit Nuclear Research CenterAtomic Energy Authority 埃及 13759

It is inferred from these studies that releases of Cd are still increasing and it is recommended that measures must be taken to reduce emissions of cadmium. Any cadmium discharged into the Egyptian environment may move from one compartment to another at varying rates, resulting in an accumulation in compartments such as soils and biota. Such accumulation can be expected to increase with continued emissions, and attention should be given to all sources of cadmium, natural as well as anthropogenic especially in the industrial cities in Egypt. Cadmium present in sewage, as well as industrial effluent (also, other liquid and solid wastes) and sewage sludge will increase levels in soils and is expected to contribute to dietary levels and body burdens. The current information indicates that such effects may have to be evaluated over long periods of time, possibly as long as 50-100 years.

关键词： cadmium accumulation dietary intake

Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

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Journal of Materials Science & Technology 1997年第5期13卷 383-388页

作者： Soliman, H.M. Mohamed, K.E. Abd El-Azim, M.E. Hammad, F.H. Metallurgy Dept. Atomic Energy Authority Cairo Egypt

Low and medium carbon steels were aluminized by the pack aluminizing technique using halideactivated pure-Al and Fe-Al packs. The effect of mixture composition, aluminizing temperatureand time and C content of the steel substrate on the structure and thickness of the aluminidelayer, and on the oxidation resistance was investigated. The optimum oxidation resistance canbe achieved with a low carbon steel substrate when the intermetallic phases Fe3Al and FeAlform the surface of the aluminide layer. In this case, the Al concentration at the surface of thealuminide coating is at least ≥15 wt pct. Formation of high Al concentration phases (FeAl3 andFe2Al5) during aluminizing should be avoided as they tend to embrittle the aluminide layer andreduce its oxidation resistance.

关键词： OO Figure Oxidation Resistance of the Aluminide Coating Formed on Carbon Steels

The performance of activated carbon/NiFe_(2)O_(4) magnetic composite to retain heavy metal ions from aqueous solution

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Chinese Journal of Chemical Engineering 2021年第1期34卷 135-145页

作者： S.I.Moussa M.M.S.Ali Reda R.Sheha Nuclear Chem.Dept. Hot Lab CenterAtomic Energy AuthorityCairo 13759Egypt Analytical Chem.Dept. Hot Lab CenterAtomic Energy AuthorityCairo 13759Egypt

A novel magnetic activated carbon composite(AC/NiF) was synthesized by a precipitation method and applied in retention of Cu(Ⅱ),and Zn(Ⅱ) ions from aqueous *** impact of different sorption parameters such as:equilibration time,solution pH value,competing cations and ionic strength on the amount sorbed of Cu(Ⅱ),and Zn(Ⅱ) was *** illustrated that the magnetic composite had retention ability towards both metal ions significantly higher than that of activated carbon(AC).The magnetic composite exhibited an affinity to adsorb Cu(Ⅱ) higher than Zn(Ⅱ) *** maximum sorption capacities(Q_(max)) of the applied magnetic composite(AC/NiF)towards Cu(Ⅱ) and Zn(Ⅱ) were 105.8 and 75.1 mg·g^(-1),*** of Cu(Ⅱ) and Zn(Ⅱ) was proposed to be achieved though an ion exchange and surface adsorption in neutral conditions,while precipitation was believed to be the relevant mechanism in their removal from basic *** kinetic studies showed that sorption process followed the kinetics of pseudo-second-order reactions with rate constant of 3 × 10^(-3) and 2 × 10^(-3) min^(-1)for sorption of Cu(Ⅱ) and Zn(Ⅱ) onto AC/NiF *** of Cu(Ⅱ) slightly decreased with increasing the ionic strength of aqueous solution,using NaCl as a background *** contrast,presence of Mn(Ⅱ),Mg(Ⅱ)and Co(Ⅱ) in reaction solutions highly depressed the sorption of Cu(Ⅱ) and Zn(Ⅱ) with a competing efficiency followed the order:Mg(Ⅱ)> Mn(Ⅱ)> Co(Ⅱ).The magnetic composite was rapidly recovered from aqueous solution by an external magnetic field,and effectively regenerated using 0.1 mol L^(-1) HCl and 0.1 mol L^(-1) FeCl_(3) as *** of Cu(Ⅱ) and Zn(Ⅱ) onto the surface of AC/NiF composite occurred via a spontaneous *** thermodynamically favorable process had ΔH~o values of 30.9 kJ·mol^(-1) and 19.7 kJ·mol^(-1),*** results confirm that the magnetic composite can be viewed as a promising novel composite opens new opportunities f

关键词： Activated carbon Nickel ferrite Composite Mechanism

Alumina Effect on the Phase Transformation of 3Y-TZP Ceramics

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Journal of Materials Science & Technology 2008年第6期24卷 873-877页

作者： Ezzat S.Elshazly M.El-Sayed Ali S.M.El-Hout Department of Metallurgy Nuclear Research CenterAtomic Energy AuthorityCairoEgypt

The isothermal tetragonal-to-monoclinic phase transformation of 3 mol fraction Y2O3-ZrO2 ceramics contain- ing different amounts of Al2O3 during ageing in water at 130℃ for periods of time up to 40 h was investigated to explore the effect of Al2O3 addition on this transformation. The propagation of the transformation into the specimen interiors was suppressed by the addition of Al2O3. The transformation kinetics showed a nucleation and growth mechanism on the specimen surface to be dominant in the low temperature ageing in water environment.

关键词： Phase transformation 3Y-TZP Al2O3 Kinetics

Localized Corrosion Behavior of 6% Mo Super Austenitic & 316L Stainless Steels in Low pH 3% NaCl Solution

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Journal of Materials Science & Technology 2005年第4期21卷 465-469页

作者： M.M.A.Gad H.G.Salem A.M.Nasreldin H.Sabry A.A.EI-Sayed Metallurgy Department Atomic Energy Authority Cairo EgyptMechanical Engineering Department AUC Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo EgyptEuropean Neighbourhood and Partnership Instrument (ENPI) Cairo EgyptMetallurgy Department Atomic Energy Authority Cairo Egypt

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and 6% Mo super austenitic in acidified 3% NaCl solution at room *** results showed that 6% Mo alloy possessed a remarkable resistance to crevice corrosion compared with 316L alloy when they are tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 mV （SCE）. The corresponding value for 6% Mo alloy could not reach up to the potential value of 700 mV （SCE）. 316L alloy suffered extremely from crevice corrosion at room temperature （about 25℃）, which indicates that the critical crevice corrosion temperature, below which crevice corrosion does not occur, was lower than the test temperature. For 6% Mo alloy, the critical crevice corrosion temperature was higher than the testing temperature. Electrochemical parameters indicated that 6% Mo alloy exhibited higher crevice corrosion resistance than 316L alloy.

关键词： Crevice corrosion 6% Mo super austenitic Conventional 316L Critical crevice temperature