Sharif Digital Repository

Electrodeposion of Zn-Ni Alloy Nanometer Multilayer has been studied. The investigations show that Multilayer coatings have more corrosion resistance than a Monolayer. The electrodeposition of the multilayer coatings was performed with the single bath technique. The sulfate-borate bath has been used for electrodeposition of the Multilayer coatings. The switching cathode density current has been used for the multilayer coatings in cathode current densities of 20, 30, 40, and 50 mA.cm-2. The number of layers with constant overall thickness of 2 µm was 20, 40, 80, and 100. The composition of layers varied between 5-11% wt Ni with the values of cathode current densities. The Response Surface... 

The multilayer coating (Zn-Ni)1/(Zn-Ni)2 is deposited from a single bath with a zincate-sulfate compound and by changing the current density. The effect of current density and the number of layers on the chemical composition, surface morphology, roughness, phase structure, and corrosion resistance of multilayer coatings respectively using atomic absorption spectroscopy, FE-SEM microscope, roughness tests, X-ray analysis, and electrochemical techniques such as Tafel polarization and impedance was investigated and compared with single-layer coatings. Because the amount of nickel in the composition of the coatings is less than 27%, in all the studied currents, the deposition is anomalous. The... 

An inexpensive microfluidic chip–silicon rubber–based system was fabricated. A triangle–shaped micro canal with a 135 µm width and 234 µm depth was grooved by laser ablation technique. The groove was sealed by a thin glass cover while two pieces of stainless steel tubings were connected to each side of canal. Then, a polyaniline film with a thickness of 17±1 µm was synthesized on the walls of the canal by chemical oxidation using a syringe pump to deliver the relevant reagents. The microfluidic system was eventually connected to gas chromatography-mass spectrometry. To evaluate the capability of the constructed fluidic system, it was implemented to the analysis of sub–mL volumes of... 

The aim of this study was electrodeposition of Zn-Ni-P/Zn-Ni multilayer coatings by single-bath method from a citrate bath to produce a sacrificial coating with high barrier properties compared to Zn-Ni monolayer coating. The coatings that were prepared at 10 mA/cm2 was Zn-Ni-P (Ni-rich and percentage of zinc, nickel and phosphorus, respectively: 40, 50 and 10 %), and the alloy deposited in 60 mA/cm2 were practically Zn-Ni (Zn-rich, 85% zinc) and almost phosphorus free. Galvanostatic pulse deposition method through switching of the current density between the two values mentioned in monolayers (10 and 60 mA/cm2) in different time periods to create bilayers corresponding to the monolayers,... 

The aim of this project is electrodeposition of Cu/Ni-P multi-layer coating and investigating the nucleation and growth mechanisms of the deposits. To evaluate the effect of the selected bath on the kinetics of the process and deposition, cyclic voltammetry and chronoamperometry studies were conducted and electrodeposition mechanism was obtained three-dimensional instantaneous nucleation and growth controlled by diffusion. Potentiostatic pulse-deposition method with potential steps -0.3 and -1.1 V vs SCE was selected for deposition of Cu/Ni-P multi-layers. In order to demonstrate the effect of monolayer thickness on the properties of the final coating, multiple layers with various monolayers... 

Electrochemical deposition of multilayer coatings is one of the surface engineering techniques to create thin surface layers with a controlled structure in order to create desirable surface properties. In this research, the nickel-iron-silicon carbide multilayer coating is deposited from a single bath with a sulfate composition and by changing the current density between two values (10 and 40 mA/cm2). The number of layers in multilayer coating was 4, 8, 16, 32.The effect of current density and the number of layers on chemical composition, surface morphology, phase structure, corrosion resistance, nano hardness measurement, wear resistance of multilayer coatings respectively using electron...