Showing 24 results for Deposition
Barzegar Alamdarit B., Ashrafi Zadeh S.n., Ashrafi Zadeh F.,
Volume 1, Issue 2 (6-2004)
Abstract
In the current research, the optimum conditions for the electrolytic deposition of TiO2 coatings on titanium pieces were experimentally investigated. Flat pieces of commercially available titanium with dimensions of 50 x20 x3 mm were used as the anode and cathode electrodes. The coatings were applied on the cathode in an electrolyte solution essentially from water and methanol, containing different amounts of TiCI4, and H202. Coatings of sufficient thickness and adequate adhesion to the substrate were obtained at the optimum conditions of theELD process. The latter conditions were electrode gap distance of 3 cm, TiCl4 concentration of 0.005M, H202 concentration of 0.1 M, current density of 35 mA/cm2, methanol/water volume ratio of 9, and pH of the electrolyte in the vicinity of 1.40. Results of XRD analysis revealed the presence of anatase crystals of titanium oxide in the coated layers, where the deposited coating was treated at some temperatures in the range of 400 to 600°C for a period of at least 2 hours. Scanning electron microscopy (SEM) pictures also confirmed the formation of a uniform coating layer with cracked suiface area. At the optimum conditions of the process coatings with thicknesses of up to 10 flm were easily obtained through the application of one to three deposited layers.
Saremi M., Motaghi Golshan B.,
Volume 3, Issue 3 (12-2006)
Abstract
A film of osteoconductive and biocompatible material on biomedical metallic implants can create bioactivity of the implant and shorten healing time. Hydroxyapatite, that is the most important mineral part of human bone, was coated on Ti6Al4V using cathodic electrode position process. Pulse electrode position technique was used and the effects of different parameters such as potential, duty cycle (on time/ (on time+ off time)), temperature and current density on the morphology of the deposits were examined. Nano size deposits were formed under controlled temperature and optimization of voltage and current density.
Mr Mohammadtaher Safarzadeh, Mr Seyed Mohammad Ali Boutorabi, Mr Asghar Arab,
Volume 7, Issue 3 (8-2010)
Abstract
The effects of anodizing condition and post treatment on the growth of nickel nanowires, were investigated. A two-step anodizing process was applied in phosphoric and oxalic acid solution. Nickel electrochemical plating was applied to fill Anodic Aluminum Oxide (AAO) pores. For pore filling enhancement, AAO surfaces were treated by silver predeposition. After electroplating, aluminum and oxide layer of some specimens were removed. The results showed that silver preplating increases the pore filling and as the applied voltage becomes higher, the pores diameter decreases.
Z. Ghaferi, K. Raeissi, M. A. Golozar,, A. Saatchi, S. Kabi,
Volume 7, Issue 4 (10-2010)
Abstract
Abstract:
current densities. Electrochemical impedance spectroscopy (EIS) results showed that the codeposition mechanism of
tungsten in Ni-W deposition is the reduction of tungsten oxide which changed to the reduction of tungsten-containing
ion complexes at higher current densities. In Co-W electrodeposition, the tungsten codeposition takes place via
reduction of tungsten oxide, although, the role of tungsten-containing complexes at higher current densities cannot be
ruled out. The surface morphology of Ni-W coatings was crack-free and was strongly dependent on deposition current
density. In addition, higher grain size and lower tungsten content were obtained by increasing the current density. In
Co-W coatings, no obvious variation in surface morphology was observed except for the fine cracks appeared at
higher current densities. In this system the grain size remained almost constant with increasing current density. The
microhardness values of Ni-W and Co-W coatings decreased due to the increase in the grain size and/or decrease in
tungsten content.
Ni-W and Co-W alloy nanocrystalline coatings were electrodeposited on copper substrate at different
P. Samadi, M. Reza Afshar, M. R. Aboutalebi, S. H. Seyedein,
Volume 9, Issue 1 (3-2012)
Abstract
Electrochemical coating processes are significantly affected by applied magnetic fields due to the generation of electromagnetic forces. The present research work has been undertaken to study the effect of coating parameters such as current density and alumina concentration on the characteristics of Ni-Al2O3 composite coating under static magnetic field. Ni-Al2O3 composite coating was applied on a mild steel substrate using conventional Watts solution containing Al2O3 particles with and without magnetic field. The coating microstructure and Al2O3 particle density in the coating layer were examined by scanning electron microscopy (SEM). It was found that the applied magnetic field made the coating structure finer and leads to the increases of the particle content in the coating. However, the results confirmed that the magnetic forces inversely affected the particle density in the coating at higher current density than that of normal coating process.
M. R. Zamanzad-Ghavidel,, K. Raeissi, A. Saatchi,
Volume 9, Issue 2 (6-2012)
Abstract
Abstract: Nickel was electrodeposited onto copper substrates with high {111} and {400} peak intensities. The grain size of coatings deposited onto the copper substrate with a higher {111} peak intensity was finer. Spheroidized pyramid morphology was obtained at low current densities on both copper substrates. By increasing the deposition current density, grain size of the coating was increased for both substrates and eventually a mixed morphology of pyramids and blocks was appeared without further increase in grain size. This decreased the anodic exchange current density probably due to the decrease of surface roughness and led to a lower corrosion rate.
S.r. Allahkaram, H. Mazaheri,
Volume 11, Issue 3 (9-2014)
Abstract
Ni-P Electroless coatings provide appropriate resistance to wear and corrosion. Co-deposition of particles
between layers can improve their properties, especially general corrosion and erosion-corrosion behavior by means
of nano diamond as reinforcing particles. In this study Ni-P/nano diamond composite deposition were deposited on
steel substrate. Structure of the coatings and corrosion resistance of theme were investigated by scanning electron
microscopy and corrosion tests in salty media. The composite structure of the deposit was evaluated as nano size
without using any surfactants. Also results for the composite coating show better corrosion protection and higher
hardness comparing with as -deposited Ni-P. The optimum concentration of diamond nanometer particles were found
by evaluation of scanning electron microscopy pictures, hardness measurement, linear polarization and
electrochemical impedance spectroscopy results
M. Azizi, M. Soltanieh,
Volume 11, Issue 3 (9-2014)
Abstract
In the present research, to form niobium carbide coating on the surface of AISI L2 steel Thermo-Reactive
Deposition method (TRD) in a molten bath was used. Niobium carbide coating treatment was carried out at 1173 K,
1273 K, and 1373 K for 2, 4, and 8 hours. The molten bath contained 20wt.% borax (Na2B4O7), 5 wt.% boric acid
(B2O3), and 75 wt.% ferro-niobium. The presence and properties of the coated layer were studied by means of Optical
Microscopy (OM), Scanning Electron Microscopy (SEM), and X-Ray Diffraction (XRD) analysis. The thickness of
coating ranged between 6.6 µm to 33µm depending on treatment time, and temperature. The effects of treatment time
and temperature on the coating thickness were studied. Kinetic study of the formation of NbC coating showed that
growth of the coating is under the control of diffusion. The activation energy of the process was estimated to be 122
kJ/mol. A practical formula to estimate the coating thickness was suggested.
Z. Abadi, S. M. Bidoki, V. Mottaghitalab, A. Benvidi, A. Shams-Nateri,
Volume 11, Issue 3 (9-2014)
Abstract
Silver nanoparticles are being given considerable attention because of their interesting properties and
potential applications. One such exploitable use is as the major constituent of conductive inks and pastes used for
printing various electronic components. This paper presents a novel direct-writing process for fabrication of the first
deposited silver nanoparticles (AgNPs) (50-200nm) electrode via a thermal inkjet printer. In this method, AgNPs were
chemically deposited by ejection of ascorbic acid and silver nitrate solutions onto different substrates such as paper
and textile fabrics. Silver deposited patterns were used as electrodes in different electrochemical experiments and their
morphology was also investigated in SEM observations. The highest conductivity of deposited electrodes obtained on
paper as the substrate was found to be around 5.54x105 S/m. Inkjet fabricated electrodes exhibited acceptable
electrochemical behavior in experiments designed for measuring the concentration of hydrogen peroxide as a
fundamental procedure for early determination of glucose. This novel inkjet silver deposition technique is introduced
to be considered as a promising method for ultimate single step fabrication of different electrochemical bio-sensors.
H. Shalchian, A. Farbod, H. Beygi, S. A. Sajjadi,
Volume 12, Issue 1 (3-2015)
Abstract
High energetic aluminum nanoparticles are mainly used as additive in solid rocket propellants. However,
fabrication of these aluminized energetic materials is associated with decreasing the burning rate of propellants due
to problems such as oxidation and agglomeration of nanoparticles. In this study, to improve combustion performance
of aluminum nanoparticles, coating by metallic Ni shell was studied. Nickel coating of aluminum nanoparticles was
performed through electroless deposition (ED) subsequently, morphology and chemical composition of Ni-coated
nanoparticles were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM),
energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). These studies show that a uniform Ni layer with a
thickness of 10nm is coated on the surface of Al nanoparticles. Thermal analysis of uncoated and Ni-coated aluminum
nanoparticles was done using differential thermal analysis (DTA) and thermo gravimetric analysis (TGA). The results
of thermal analysis indicate that, coating the aluminum particles by Ni, leads to improvement in combustion
performance of aluminum nanoparticles through decreasing critical ignition temperature, ignition delay time of the
nanoparticles and promoting the ignition by exothermic chemical reactions between Al and Ni
M. Akbarzadeh, A. Shafyei, H. R. Salimijazi,
Volume 12, Issue 1 (3-2015)
Abstract
In the present study, CrN, TiN and (Ti, Cr)N coatings were deposited on D6 tool steel substrates. Physical and mechanical properties of coatings such as microstructure, thickness, phase composition, and hardness were evaluated. Phase compositions were studies by X-ray diffraction method. Mechanical properties were determined by nano-indentation technique. The friction and wear behaviour of the coatings were investigated using ball-on-disc tests under normal loads of 5, 7 and 9 N at sliding distance of 500 m, at room temperature. Scanning electron microscope equipped with energy dispersive spectroscopy, optical microscope, and 2D/3D profilometry were utilized to investigate the microstructures and wear mechanisms. Wear test results clarified that the wear resistance of (Ti, Cr)N and TiN coatings was better than that of CrN coating. The wear resistance of the (Ti, Cr)N coatings was related to the Ti content in the coatings and reduced by decreasing the Ti content. The dominant wear mechanisms were characterized to be abrasive and tribochemical wear
M. S. Mahmoudi Jozee, S. Sanjabi, O. Mirzaee,
Volume 13, Issue 3 (9-2016)
Abstract
A homogenous TiO2 / multi-walled carbon nanotubes(MWCNTs) composite film were prepared by electrophoretic co-deposition from organic suspension on a stainless steel substrate. In this study, MWCNTs was incorporated to the coating because of their long structure and their capability to be functionalized by different inorganic groups on the surface. FTIR spectroscopy showed the existence of carboxylic groups on the modified carbon nanotubes surface. The effect of applied electrical fields, deposition time and concentration of nanoparticulates on coatings morphology were investigated by scanning electron microscopy. It was found that combination of MWCNTs within TiO2 matrix eliminating micro cracks presented on TiO2 coating. Also, by increasing the deposition voltages, micro cracks were increased. SEM observation of the coatings revealed that TiO2/multi-walled carbon nanotubes coatings produced from optimized electric field was uniform and had good adhesive to the substrate.
S. Akbarzadeh, S.r. Allahkaram, S. Mahdavi,
Volume 15, Issue 2 (6-2018)
Abstract
Tin-Zinc alloy coatings have many applications because of their unique properties such as corrosion resistance, solderability and flexibility. In this study, the effect of current density, temperature and pH on chemical composition, cathodic current efficiency, morphology and structures of the coatings was investigated. The results illustrated that, at low current densities (<0.5 mA/cm2), the coatings were relatively pure tin, but Zn content increased with enhancing the current density. At higher currents a relatively pure Zn film was obtained. Temperature and pH also affected chemical composition of the alloy films. Zn content of the coatings was decreased by increasing the temperature, while its variation with pH had ascending-descending trend. Morphological investigation of the coatings revealed that increasing Zn content of deposits led to porous, rough and fine grained films.
F. Farzan, H. R. Shahverdi, F. Malek Ghaeni,
Volume 15, Issue 2 (6-2018)
Abstract
Recently, wear resistant properties of metallic glasses has attracted a lot of interest. Because the surface of metallic glasses are prone to phase transformation, finding the effects of test condition on structure and wear behavior of metallic glasses is important. In this research, by using an automated electrospark deposition (ESD), a layer of Fe
51Cr
18Mo
7B
16C
4Nb
4 was deposited on AISI 316l stainless steel. Metallographic,
scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDS) analyses of the coating were conducted for measuring the thickness and analyzing composition of the coating. X-ray diffraction (XRD), Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) investigations showed that the structure of the coating was amorphous. Ball on disc wear tests were conducted in dry and wet conditions and Ringer’s solution was chosen as the wetting agent. The wear test results showed that the coefficient of friction in dry condition was lower than the wet condition and wear modes were fatigue and corrosive wear in dry and wet conditions respectively. SEM and EDS analyses showed different features and elemental inhomogeneity on the surface of the dry wear track, which were not detectable in wet wear track. In addition, activation of diffusion process and formation of carbides and borides were observed on the wear track in dry condition.
M. Minbashi, R. Zarei Moghadam, M. H. Ehsani, H. Rezagholipour Dizaji, M. Omrani,
Volume 16, Issue 3 (9-2019)
Abstract
Zigzag ZnS thin films prepared by thermal evaporation method using glancing angle deposition (GLAD) technique. ZnS films with zigzag structure were produced at deposition angles of 0˚, 60˚ and 80˚ at room temperature on glass substrates. Surface morphology of the films w::as char::acterized by using field emission scanning electron microscopy (FESEM). The optical properties of the specimens were investigated by using UV-Vis spectroscopy technique. To characterize the porosity of the simulated structures, the PoreSTAT software which analyses the NASCAM software was employed. The optical transmissions of the samples were calculated by using NASCAM optics package. The simulation results are completely in agreement with the experimental results.
Rabah Bobaaya, Omar Allaoui, Mokhtar Djendel, Samir Benaniba,
Volume 18, Issue 3 (9-2021)
Abstract
Coatings based on chromium borides and chromium carbides are commonly employed in applications requiring mechanical performance, such as high hardness and low friction coefficient, as well as corrosion resistance. In this work, we made layers of chromium borides and chromium carbides on the surface of low carbon steel through some specific treatments. For chromium borides, the boriding treatment in a solid medium at 900 °C for 4 hours followed by chromium electroplating on the steel surface and finally the application of annealing treatment at temperatures at 950 °C for 1 and 2 hours. For chromium carbides, the cementation in a solid medium followed by electroplating of chromium on the surface and finally the application of annealing treatment at temperatures between 500 and 1100 °C for 1 hour. The obtained results show that, in the first case, boron diffusion and chromium deposition lead to chromium borides on the treated surface. Similarly, for the second case, the cemented layer and the chromium deposited on the surface combine to form chromium carbides on the treated surface after annealing. The characteristics of the chromium borides and chromium carbides obtained are very similar to those of chromium borides and chromium carbides obtained by other processes.
Yemurai Vengesa, Arash Fattah-Alhosseini, Hassan Elmkhah, Omid Imantalab,
Volume 18, Issue 4 (12-2021)
Abstract
The main purpose of this investigation is to assess the effect of post-deposition annealing treatment on the electrochemical behavior of TiN coating developed on AISI 304 stainless steel substrate using cathodic arc evaporation physical vapor deposition (CAE-PVD). Post-annealing treatment at 400 ºC was performed on the coated substrate for 1 h. The studied samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) tests. The preferred orientation of TiN (111) was identified by XRD patterns and the crystallinity of the coating increased after annealing treatment. SEM observations indicated that TiN coatings free of cracks were successfully developed on the substrate. The electrochemical measurements elucidated that the annealed coating had better corrosion resistance compared to that of the as-deposited coating with a lower current corrosion density. This investigation implied that improved corrosion performance of the TiN coating can achieved by performing post-deposition annealing treatment.
Parviz Parviz Mohamadian Samim, Arash Fattah-Alhosseini, Hassan Elmkhah, Omid Imantalab,
Volume 19, Issue 1 (3-2022)
Abstract
In this study, CrN/ZrN multilayer nanostructured coatings with different bilayers (10, 20, and 30) were created by the cathodic arc evaporation. The electrochemical behavior of samples was evaluated by polarization and impedance spectroscopy tests in the Ringer medium and the pin on disk test was used to investigate the tribological behavior of the samples. The results of measurements showed that the electrochemical and tribological behavior of the coatings depends on the number of bilayers and by rising the number of bilayers, the coating shows higher corrosion resistance and better tribological performance. Field emission scanning electron microscopy (FE-SEM) images of the specimens after exposure to the corrosion medium showed that the number of surface cavities were formed by the coating that had the highest number of bilayers comparing with other coatings were quite fewer in number and smaller in diameter. The results of the pin on disk test showed that by increasing the number of bilayers from 10 to 30, the coefficient of friction and wear rate decreased and the 30L coating showed better wear resistance.
Mohammad Roostaei, Hossein Aghajani, Majid Abbasi, Behzad Abasht,
Volume 19, Issue 3 (9-2022)
Abstract
This study investigates the synthesis of Al/MoS2 nanocomposite coating by the electro spark deposition (ESD) method for its lubricating properties. ESD method was selected because it is a very easy, rapid, and cost-saving method and the resulting coating has a strong bonding with the substrate. As a substrate, a Ti-6Al-4V alloy sheet containing 6.12 % Al, 4.06 % V, 0.19% Fe, and 0.05 % Ni was used. For coating, an aluminum-molybdenum disulfide composite electrode in the form of a cylindrical rod was employed. Three frequencies of 5, 8, and 11 kHz, three current limits of 15, 25, and 35 amps, and three duty cycles of 50, 60, and 70% were used in the coating operation. AFM analysis was used to study the topography, morphology, and calculate roughness. The samples were then subjected to hardness tests. To determine the wear resistance of the samples, pin on disk tests were performed. XRD analysis was performed to identify the phases on the surface of the coated samples. SEM was used to examine the microstructure of the coating before and after wear testing, in order to determine the wear mechanism. The results indicated that the Al/MoS2 nanocomposite coating was synthesized on the substrate surface. The hardness of the reference sample is 353 Vickers, and that of the coated samples is about 200 Vickers. For the reference sample, the roughness was measured at 15.7 nm, and for the coated sample at 268.1 nm. As spark energy increased, the coefficient of friction increased by approximately 0.09. As spark energy increased, the wear rate increased by 27%. A significant increase in the Lancaster coefficient occurred around 5 joules of energy. According to the wear rate results, the sample with the lowest thickness wears 4% less than the sample with the highest thickness. The wear rate of sample 351170 is 78% lower than that of sample 150550.
Deepak Jagannathana, Hiriyannaiah Adarsha, Keshavamurthy Ramaiah, Ramkumar Prabhud,
Volume 20, Issue 3 (9-2023)
Abstract
Several extensive researches are being carried out in the field of 3D printing. Polymer matrices, such as High-Density Polyethylene (HDPE), are less explored in particular on the microstructure and mechanical properties of HDPE composites developed via Fused Deposition Modelling (FDM) process. Very scarce amount of works is devoted to study HDPE’s reinforced with carbon nano-tubes (CNT’s) . In the present work, we report on the mechanical properties of HDPE composites prepared via FDM process. Varying proportions of CNTs ( 0.5, 1, 1.5 and 2%) are used as reinforcements. It is found that increasing CNT content enhances impact and tensile strength, with HDPE/2.0%CNT outperforming pure HDPE by approximately 71.6% and 25.4%, respectively. HDPE/2.0%CNT composite also showed Young's modulus approximately 49.2% higher than pure HDPE. According to fracture analysis, pure HDPE failed near ductile, whereas composites failed brittle. CNTs occupy the free positions in the polymeric chains, and their tendency to restrict chain mobility causes HDPE to lose ductility and begin to behave brittle. The use of CNTs as reinforcement successfully improved the mechanical properties of HDPE.
