Sharif Digital Repository

In this research a copper- diamond nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without disturbing cooper's specific physical properties as like as electrical and thermal conductivity. The mechanism of electrodeposition was analyzed with the technique of Cyclic Voltammetry, Chronopotentiometry and Chronoamperometry. The morphology, hardness, scratch resistance, elastic modulus and friction factor of coating were investigated by using a scanning electron microscope (SEM) and atomic force microscope(AFM) also the mechanism of co- deposition of diamond particles with copper was corresponded with... 

A study of the electro-oxidation and surface reactions of C1 compounds on Ni and Cu electrodes, Ni(111) and Cu (111) has been performed by methods of cyclic voltammetry, BOC-MP and DFT. The diffusion coefficients and activation energies of the electro-oxidation of methanol and formaldehyde in alkaline solution on Ni electrode have been derived. Values around 2.27×10-6 cm2s-1, 1.98×10-5cm2s-1, 12.15 Kcal mol-1 and 11.65 Kcal mol-1 have been obtained respectively. In theoretical study , the elimination of hydrogen from CH3 and CH2 groups has been proposed as a mechanism in surface reactions of methanol and formaldehyde on Ni(111) ... 

In this work, the recovery of rhenium from ferromolybdenum furnace outgoing dust in semi industrial scale was conducted. The ferromolybdenum furnace outgoing dust contains rhenium as major part and large amounts of molybdenum plus Iron and copper as impurities. An overall flow sheet, consist of leaching, solvent extraction and precipitation methods, was design to recovery and purification of rhenium. Firstly, ferromolybdenum furnace outgoing dust was subjected to leaching treatment by 10 g/L sulfuric as solvent at 85 C. Secondly, solvent extraction method was employed, using LIX984N 10 %vol, to separate copper from rhenium containing solution. The results of MacCab thiele diagram for... 

In this project two manganese(III) complexes with 2-(2',4'-dihydroxyphenyl)-2-oxazoline ligand, [Mn(4-OHphox)3], [Mn(4-OHphox)2(CH3OH)2]ClO4 and a copper(II) complex with 2-(2'-hydroxy)-2-oxazoline ligand have been synthesized. The complexes and the ligands were characterized by elemental analysis (CHN), FT-IR and 1HNMR spectroscopies. Oxidation of sulfides catalyzed by these complexes using urea-hydrogen peroxide (UHP) as oxidant within short reaction times (5 min) was investigated. The results showed that catalytic efficiency of [Mn(4-OHphox)3] complex was better than other complexes. Optimization of the catalyst system presented a high selectivity of sulfoxide (90-100%) in a few time (5... 

A new method for production of bimetallic rods, utilizing the equal channel angular extrusion (ECAE) process has been introduced before by previous researchers, but no attempt has been made to assess the effect of different temperatures and holding times in order to achieve a diffusional bond between the mating surfaces. In present research copper sheathed aluminum rods have been ECAEed at room temperature and subsequently held at a constant ECAE pressure, at different temperatures and holding times to produce a diffusional bond between the copper sheath and the aluminum core. The bonding quality of the joints was examined by shear strength test. The microstructure examinations were carried... 

Mechanical properties of commercial purity copper sheets are improved and grain size of material is refined into Nano scale after using a severe plastic deformation technique called constrained groove pressing (CGP). Since there are high levels of stored energy and non-equilibrium grain boundaries in nanostructure, annealing behavior and thermal stability of material should be investigated. Although there is not a clear distinction between annealing phenomena, it is essential to determine the intervals of annealing phenomena in order to control their sequences on mechanical properties and nanostructure. Also mechanisms of annealing phenomena should be determined to realize annealing behavior... 

In this work, Unity Bond Index-Quadratic Exponential Potential (UBI-QEP) method was applied to investigate the decomposition routs of -halo alcohols on Ni(111) and Cu(111) crystallographic planes and Ni2Cu1(111) and Ni1Cu2(111) alloys. UBI-QEP calculates energetics, H and E, along reactions routes using heats of atomic adsorption as empirical inputs and in this way avoids needs to be very specific about every system. The results of analysis of -halo-propanols on Ni and Cu surfaces are in good agreement with experimental findings; namely in the formation of carbon-monoxide, ethylene, water and hydrogen over Ni and propene and water over Cu. Predicted activity of -halo-propanols,... 

Recently, the size of copper interconnects is going to reach lower than the mean free path of electrons for copper. In this situation, we should consider the effect of other scattering mechanisms as well as thermal scattering on copper thin films. In this work we study both DC size effect and anomalous skin effect on resistivity by a Monte Carlo method. Contribution of each scattering mechanism and the interaction between them are analyzed separately. The structure of electrical field and distribution of current in thin films have also been studied. Investigating of the effect of exact nature of surface scattering and grain boundary scattering on resistivity is one of the interests of this... 

While digital IC technology scales down, the impact of size effects in copper interconnects become more important because wire dimensions reach the same order of electron mean free path yielding increased resistivity of metal due to surface and grain boundary scatterings. Hence, because of their longer MFP, Carbon nanotubes are proposed as potential candidates for replacing copper interconnects. Furthermore, wires, especially power and ground lines, are becoming more and more vulnerable to electromigration because of rapid grows in current densities which increases the temperature of IC and interconnects as well. Sub-ambient cooling has long been suggested for improving the performance of... 

In order to obtain more insight into the enzymatic oxygen-atom-transfer (OAT) process and elucidate the relation between the structure and function of the synthetic model complexes, new molybdenum and tungsten complexes containing different chelating ligands were systematically prepared and investigated. Herein, the cis-dioxo-molybdenum(VI) complexes with new aromatic dithiolene ligands, formulated as [MoO2(2,3ppdt)2]NR4 and [MoO2(3,4ppdt)2]NR4, (2,3ppdt= pyrido-2,3-pyrazine-2,3-dithiolato, 3,4ppdt= pyrido-3,4-pyrazine-2,3-dithiol and R= Et or Bu) were prepared and investigated by elemental analysis, IR, 1H NMR and UV-Vis spectroscopic methods. An OAT reaction of [MoO2(2,3ppdt)2]2– with PPh3... 

Lots of investigations have been focused on dissimilar friction stir welding of aluminum and copper plates. Sever plastic deformation is a way to produce nanostructure materials, without changing in their appearance. The size of sever plastic deformed sheets in light of restriction in load capacity and equipments is limited and less industrial application can be found. Joining is the best solution for this problem. Therefore in this study, dissimilar friction stir welding of severely plastic deformed aluminum and copper sheets has been investigated. Friction stir welding is one of the best methods to join ultrafine grain materials.In this study, 3 mm-thick 1050 aluminum alloy and... 

Roll bonding process is commonly used for the production of multilayer sheets. In the present study, using the roll bonding process, two layer sheets of copper - stainless steel were produced. In this case bonding strength was measured by peeling test at different statges and the quality of bonding was evaluated by SEM and Stereo Electron Microscope. The cross-sections of the bonding of rolled and annealed samples was investigated by optical microscopy. Also using EDAX analysis and EDS, the chemical composition of formed transition layer and the size of its interface at different temperature are measured respectively and the change in mechanical properties was investigated by tensile test... 

Graphene is pure carbon in the form of a very thin, nearly transparent sheet, one atom thick. It is remarkably strong for its very low weight. Graphene is a novel particle that can improve adsorption properties. We use graphene for Iodine gas adsorption. Iodine-131 (usually in the chemical form of iodide) is a component of nuclear fallout, and is particularly dangerous owing to the thyroid gland's propensity to concentrate ingested iodine, where it is kept for periods longer than this isotope's radiological half-life of eight days. For this reason, if people are expected to be exposed to a significant amount of environmental radioactive iodine (iodine-131 in fallout), they may be instructed... 

Microbiologically Influenced Corrosion (MIC) of concrete sewer ptpes and wastewater collection systems has been reported in many places of the world. Recently, numerous copper compounds have been used for bacterial growth control in sewer pipes. In this thesis, bath parameterswere optimized in order to maximize copper osmosis to the porous concrete matrix.Concrete pipes were electrochemically coated inCopper Lactate bath in a constant current mode (1=0.6 A), while temperature was set to 25, 50, 75 and 95
°Cand pH to 9,10 and 11. Specimens were then characterized by scanning electron

microscopy, optical microscopy, XRD andAAS. Copper Osmosis was highest in pH=9 and... 

In this research a copper- Tungsten carbided nanocomposite coating prepared by electrodeposition from a sulfate bath in order to increase the hardness and erosion resistance of cooper without loosing cooper's specific physical properties as like as electrical and thermal conductivity. Various parameters were evaluated for finding significant factors in electrodeposition of Cu-Co/WC composite. Current density and concentration of WC and SDS were selected as affective factors. The morphology and structure were characterized by XRD and SEM. The mechanical properties of the coatings, such as hardness, wear resistance and surface roughness were studied with Vickers hardness indentation; pin on... 

The Cu2ZnSnS4 (CZTS) quaternary compound, with suitable optical and electrical properties, is one of the most interesting materials for absorber layer of thin film solar cell. Since all constituents of CZTS, are abundant in earth’s crust and non-toxic, it is a proper replacement for the materials like CdTe and CuInSe2. The CZTS pellet was synthesized by the solid-state reaction and deposited on soda lime glass substrates by pulsed laser deposition (PLD) method. PLD technique has the advantages of offering stoichiometric preservation during the materials transformation from target to substrate and good crystallinity due to the highly energetic species. CZTS has was deposited in order to... 

In this study, leaching of Sarcheshmeh Reverberatory Furnace Dust was investigated in the H2SO4-O3 media. Response surface methodology based on central composite face-centered design (RSM-CCF), was applied to optimize the operating parameters. The optimum conditions to obtain the main goal of maximum copper and minimum iron dissolution from dust were identified to be temperature of 30˚C, leaching time of 3hr, initial pH of 0.5, pulp density of 20% and ozone flow rate of 1g/h. The copper and iron concentrations of leaching solution were found to be 27.11 and 0.89983 g/L under the optimum conditions, respectively. The results showed that selective copper extraction from the dust could be... 

In this study effect of air flow rate, particle size and oxygen excess on roasting of copper concentrate in a fluidized bed reactor were investigated. Copper concentrate in this work was from sarcheshme copper mine. For determination of the weight percentage of remaining sulfur, calcins were analyzed by XRD. The effect of air flow rate was studied at 211,250 and 312 lit/min. The results indicate that an increase in air flow rate led to a decrease in amount of sulfur in the calcin. For study the effect of oxygen excess roasting were done with 20,21 and 23 volume percent of oxygen and the results were the same as the effect of air flow rate. For study the effect of particle size, roasting were... 

Commercial pure copper sheets after primary annealing were severely deformed to amount of 2.32 by Constrained Groove Pressing (CGP) method. These sheets were undergone to electrical current at different heating times of 0.5, 1, 2, and 3 seconds up to four maximum temperatures of 150, 200, 250, and 300 °C without holding time. In order to compare the annealing by electrical current and without electrical current, four other samples were heated to 300 °C with holding times of 60, 90, 120, and 150 seconds in salt bath. Then, samples microstructure evolutions, hardness and shear stress values were investigated. Generally, the results depicted that inducing electrical current can accelerate the... 

In this study, Butt resistance welding of copper to aluminum wires was studied. In this regard, the effect of current, pressure, post weld heat treatment and using intermediate layer of tin on the microstructure, strength and special electrical resistance of welds were examined. Based on a series of initial tests to establish the connection with the appropriate strength, the diameter of the aluminum and copper wires respectively 3 and 3.5 mm and their length 9 and 3.5 cm were selected. In order to weld samples, currents 4.4 to 4.7 KA and pressures 0.3 and 0.5 MPa were used. Then post weld heat treatment at currents 0.5, 1 and 1.5 KA on the welded sample in the pressure 0.3 MPa and the...