Electrodeposition of copper on copper in the presence of dithiothreitol

Studies of the -SH group effect present in dithiothreitol (DTE) with respect to morphology and electrode kinetics of copper electrodeposits on the (1 1 1) plane of a copper single crystal and polycrystalline copper from highly purified solutions of acidified copper sulphate were made. At 2.0 and 5.0 mA cm^–2 there was a truncation of pyramids to layers and ridges and then to polycrystalline growth with an increase in the concentration of DTE in the bath. At higher current densities the change was from pyramids to thin hexagonal blocks, dragged pyramids and then to polycrystalline growth. Interestingly, the above morphological changes repeated at two different concentrations of DTE corresponding to two -SH groups present in the molecule. Levelling of the grains was observed at all current densities studied on a polycrystalline substrate. The electrode kinetic parameters have been correlated with the morphological changes and transport mechanisms have been proposed for different concentrations of the additive.     

Electrodeposition of copper on Cu−Zr metallic glass substrates

This paper describes an investigation of the electrodeposition of copper on Cu–Zr metallic glass in the presence of 5-sulphosalicylic acid and 2-thiouracil. The observed morphological features and electrokinetic parameters are correlated, and suitable transport mechanisms are proposed with the help of infrared studies. It was observed that Cu–Zr metallic glasses enhance the rate of decomposition of hydrogen peroxide catalytically and electrocatalytically. This was attributed to the unusual structure of the substrate and physical or chemical inhomogeneities.     

Sintering of Fused Mullite Based Particulate Composites Containing Zirconia

2r0₂ and its modified versions containing MgO and Y₂0₃ were selected as particulate reinforcement in order to achieve better mechanical properties in fused mullite. Particulate composites containing up to 25 vol% Zr0₂ and its modifications were pressed to 65% relative density at 350 MPa followed by sintering at 1650°C and 1700°C for one hour. Studies were conducted on fracture toughness, transverse rupture strength, dielectric constant, microstructure, fractography and thermal shock resistance. Composites sintered at 1700°C were found superior in properties than those sintered at 1650°C.     

Electrodeposition of copper on the copper (1 0 0) face in the presence of 2-mercaptoethanol

Observations were made of the morphological changes which occur during the electrodeposition of copper on the copper (1 0 0) plane from an acid sulphate bath and in the presence of known concentrations of 2-mercaptoethanol at various current densities. At lower current densities, there was a transition from layers to ridges and then to polycrystalline growth with increasing concentration of 2 mercaptoethanol. At higher current densities the change was from pyramids to truncated blocks, then to ridges and finally to a polycrystalline deposit. The electrokinetic parameters have been correlated with these morphological changes and transport mechanisms have been proposed for different concentrations of the addition agent.     

Sintering of mullite-based particulate composites containing ZrO2

ZrO₂ and its modified versions containing MgO and Y₂O₃ were selected as particulate reinforcement in order to achieve better mechanical properties of mullite. Particulate composites up to 25 vol % ZrO₂ and its modifications were pressed to 55% relative density at 300 MPa followed by sintering at 1600°C and 1650°C for one hour. Studies were conducted on fracture toughness, transverse rupture strength, hardness, dielectric constant, microstructure and fractography. Composites sintered at 1650°C were found superior in properties than those at 1600°C. The maximum strength of mullite composites was observed at a composition of 10 vol % ZrO₂.     

A New,Efficient and Recyclable Lanthanum(III) Oxide‐ Catalyzed C?N Cross‐Coupling

A new and efficient protocol for the C N cross‐coupling of aryl halides with heteroaromatic amines in the presence of lanthanum(III) oxide (10 mol%) as a recyclable catalyst, N,N′‐dimethylethylenediamine (DMEDA) (20 mol%) and potassium hydroxide (KOH) as a base in dimethyl sulfoxide (DMSO) at 110 °C has been developed. This inexpensive catalytic system is highly effective towards the amination of aryl halides with various nitrogen nucleophiles and is significantly tolerant towards other functional groups in the substrates.     

Copper‐Catalyzed C?NH2 Arylation of 2‐Aminobenzimidazoles and Related C‐Amino‐NH‐azoles

A copper(II)‐catalyzed selective C NH₂ arylation of 2‐aminobenzimidazoles and related C‐amino‐NH‐azoles was achieved in presence of 2,2′‐bipyridine and cesium carbonate at 60 °C under open air conditions and this is first method for the copper‐catalyzed selective C NH₂ arylation in the presence of other reactive nucleophilic sites. Previously unexplored heteroaromatics possessing multiple nucleophilic sites that are selectively arylated at the C NH₂ position are obtained, providing an exceptional tool for rapid delivery of a diverse array of medicinally important C NH(aryl) derivatives of aminoazoles without any protection/deprotection of ring N H bonds. It is first example for the selective C NH₂ arylation of 5‐aminoindazole, 4‐aminopyrazole, 5‐aminopyrazole, 9H‐purine‐6‐amine, and 1H‐pyrazolo[3,4‐d]pyrimidin‐4‐amine derivatives.

     

Effect of 2-mercaptoethanol on the electrodeposition of lead

The morphology and the electro-kinetic parameters of lead electrodeposits on polycrystalline lead have been studied in a fluoborate bath at several current densities in the presence of known concentrations of 2-mercaptoethanol. It was observed that there was a notable decrease in the grain-size at low concentrations of the addition agent and the critical concentration varied with the current density. The growth habit modification and the changes in the kinetic parameters with increasing concentrations of the addition agent and current density, were investigated. Suitable transport mechanisms were proposed with the help of IR and X-ray studies.