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phosphate-coatings
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Formation & Properties of Zn–Ca– Mn Tri – Cation’s Phosphate Coating on St37 Steels
, M.Sc. Thesis Sharif University of Technology ; Afshar, Abdollah (Supervisor) ; Ghorbani, Mohammad (Supervisor)
Abstract
Addition of heavy metal cations such as manganese and nickel in low zinc phosphating bath increases the corrosion resistance of coatings and provides more suitable substrates for painting (especially electrophoretic painting). In addition, due to accelerating property and low cost availability of heavy metal cations such as Mn, multi– cationic phosphating is cost effective. In the present study, chemical composition and operating parameters of zinc - calcium - manganese Tri- cationic phosphating solution were optimized. Then the effects of various parameters such as phosphating time, bath temperature and pH on properties of coating were investigated. According to the results, about 1 g/L was...
, M.Sc. Thesis Sharif University of Technology ; Ghorbani, Mohammad (Supervisor)
Abstract
Phosphating is one of the most procedures as a final surface treatment or pre-treatment (lubrication and Infrastructure color) is done on ferrous and nonferrous alloys. Phosphate coating on the wire drawing, increase speed of drwing, increase die life, increased resistance to abrasion caused by the friction reduction, reduced maintenance costs and improved surface appearance are combustible and conditions. The aim of this study was to evaluate the effects of variables such as temperature, pH bath, the coating bath components concentration on coating properties and optimize calcium zinc phosphate coating on steel wire, for better lubrication and decrease friction in the wire drawing process....
Zn-Ni Electrophosphating on galvanized steel using cathodic and anodic electrochemical methods
, Article Surface and Coatings Technology ; January , 2015 ; 02578972 (ISSN) ; Afshar, A ; Aliabadi, A ; Sharif University of Technology
Elsevier
2015
Abstract
Electrophosphating is the novel method for accelerating the low temperature phosphating bath. This method can be performed as cathodic and anodic treatments. Both of them influence the coating deposition mechanism and therefore coating properties. In this study Zn-Ni electrophosphate coating was applied on galvanized steel using cathodic and anodic electrochemical methods. Microstructure, composition and corrosion resistance of coating were characterized by using a scanning electron microscopy, X-ray diffraction method and potentiodynamic polarization test respectively. The results of this study indicated that, by using cathodic method, compact phosphate coating with high corrosion...
Effect of current density on DC electrochemical phosphating of stainless steel 316
, Article Surface and Coatings Technology ; Volume 205, Issue 7 , December , 2010 , Pages 2302-2306 ; 02578972 (ISSN) ; Afshar, A ; Hasannejad, H ; Sharif University of Technology
2010
Abstract
In this study, tri-cation phosphate coating of zinc, calcium and iron was applied electrochemically to stainless steel 316 substrates. Cathodic current was used as an accelerator for the phosphating process. The effects of current density on the microstructures of the coatings and the time necessary for the reduction of the oxide layer have been established. For this purpose, analyses such as chronopotentiometery, SEM, EDS and linear polarization were carried out. Results indicated that higher electrophosphating current densities result in finer crystal size of the coating. This effect is detrimental to the quality of the layer. In addition, chemical analyses of the layer revealed that the...
Zn–Ni electrophosphating on galvanized steel using cathodic and anodic electrochemical methods
, Article Surface and Coatings Technology ; Volume 306 , 2016 , Pages 497-505 ; 02578972 (ISSN) ; Afshar, A ; Aliabadi, A ; Sharif University of Technology
Elsevier B.V
2016
Abstract
Electrophosphating is the novel method for accelerating the low temperature phosphating bath. This method can be performed as cathodic and anodic treatments. Both of them influence the coating deposition mechanism and therefore coating properties. In this study Zn–Ni electrophosphate coating was applied on galvanized steel using cathodic and anodic electrochemical methods. Microstructure, composition and corrosion resistance of coating were characterized by using a scanning electron microscopy, X-ray diffraction method and potentiodynamic polarization test respectively. The results of this study indicated that, by using cathodic method, compact phosphate coating with high corrosion...
Effect of Ca2+ additives on morphology, composition and corrosion resistant of Zn-12%Ni phosphate coating
, Article Journal of Materials Research and Technology ; Volume 5, Issue 4 , 2016 , Pages 327-332 ; 22387854 (ISSN) ; Hanaei, A ; Pakseresht, A. H ; Shahbazkhan, A ; Parvini Ahmadi, N ; Baniasadi, F ; Sharif University of Technology
Elsevier Editora Ltd
Abstract
The aim of this study is to investigate the effect of phosphate solution with Ca2+ additives on weight, surface morphology and electrochemical behavior of phosphated Zn-Ni film. In order to characterize structure and morphology of surface, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied, respectively. Results showed that the main composition in produced coatings was hopeite Zn3(PO4)2·4H2O, which has high corrosion resistance. On one hand, in the presence of Ca2+ cations in solution, the weight of phosphate coating decreased, but on the other hand surface uniformity and corrosion resistance of the coating increased
Synthesis and characterisation of β-tricalcium phosphate coating on zirconia toughened alumina by biomimetic method
, Article Advances in Applied Ceramics ; Volume 112, Issue 3 , 2013 , Pages 140-145 ; 17436753 (ISSN) ; Nemati, A ; Salahi, E ; Sharif University of Technology
2013
Abstract
The present work studied bioactive coatings on the surface of ceramic biomaterials. Zirconia toughened alumina (ZTA) composites containing 15 mol.-%. Partially stabilised zirconia was prepared after 1 h sintering at 1550°C. Apatite layers were then coated onto the surfaces of composites by the biomimetic method using 1·5-2 multiply concentrations of simulated body fluid (SBF). Before treatment in SBFs, a sodium silicate layer was employed as nucleating agent to induce the formation of a calcium phosphate layer. The effect of immersion time on the morphology of the precipitate was monitored with a scanning electron microscope. X dot maps revealed that there is a relationship between...
MAO-derived hydroxyapatite-TiO 2 nanostructured bio-ceramic films on titanium
, Article Materials Research Bulletin ; Volume 47, Issue 11 , 2012 , Pages 3407-3412 ; 00255408 (ISSN) ; Golestani Fard, F ; Rezaie, H. R ; Mirhosseini, S. M. M ; Ziaee, A ; Sharif University of Technology
2012
Abstract
Micro Arc Oxidation (MAO) process was utilized to fabricate nano bioceramic TiO 2-hydroxyapatite coatings on titanium substrates. Samples were produced in electrolytes contained 1 g/l β-glycerophosphate and 5, 10 and 15 g/l calcium acetate for 3, 6 and 10 min at 350 V. The techniques including XRD, XPS, SEM, FESEM and EDX were employed to study the effect of processing parameters. Hydroxyapatite, anatase, α-tri calcium phosphate and calcium titanate phases as well as 30-60 nm-size crystals were detected in the coating layer. It was also observed that the pore volume would increase by increasing the electrolyte concentration. The growth time was also found to influence the total pore volume....
Sol-gel derived hydroxyapatite coating on TiB 2/TiB/Ti substrate
, Article Surface Engineering ; Volume 28, Issue 7 , August , 2012 , Pages 526-531 ; 02670844 (ISSN) ; Dabir, F ; Taheri, M ; Sohrabi, N ; Toroghinejad, M. R ; Sharif University of Technology
2012
Abstract
The low erosion resistance of titanium and its alloys has prevented their widespread application as joint implants. In addition, one essential requirement for the implants to bond with the living bone is the formation of a bone-like apatite on their surfaces in the host body. To enhance the erosion resistance of the surface, a diffused layer of TiB2 was formed at 1000uC on the commercial pure titanium. Hydroxyapatite was then coated on the boronised titanium by means of dip coating in a sol-gel solution. In order to confirm the biocompatibility of the specimens, they were soaked in a simulated body fluid for several days. The surface morphology of the specimens after exposure was studied by...
Formation of Zn-Ca-Ni tri cation's phosphate coating on steel and study that properties
, Article TMS 2009 - 138th Annual Meeting and Exhibition, San Francisco, CA, 15 February 2009 through 19 February 2009 ; Volume 1 , 2009 , Pages 615-623 ; 9780873397384 (ISBN) ; Afshar, A ; Sharif University of Technology
2009
Abstract
A new Zinc phosphating bath, which produces coatings at relatively lower temperatures within a reasonable time by using of chemical accelerators has been devised. Improvement of the bath performance by the addition of divalent cations like calcium, nickel has been studied. Bath formulation and operating conditions have been optimized by coating weight determinations. Stable samples of phosphating formulations with and without calcium and nickel salts were prepared and the structure and morphology of the phosphate coatings were determined by using X-ray diffraction (XRD) techniques, scanning electron microscopy. ASTMB117 salt spray test and electrochemical impedance spectroscopy (EIS) were...
Improved electrochemical performance of plasma electrolytic oxidation coating on titanium in simulated body fluid
, Article Journal of Materials Engineering and Performance ; Volume 28, Issue 7 , 2019 , Pages 4120-4127 ; 10599495 (ISSN) ; Aliasghari, S ; Ghorbani, M ; Sharif University of Technology
Springer New York LLC
2019
Abstract
The effect of plasma electrolytic oxidation (PEO) pre-treatments on corrosion behavior of titanium in simulated body fluid (SBF) is investigated. Three pre-treatments are compared, using silicate, calcium phosphate and mixed silicate and calcium phosphate (1:1) electrolytes, respectively. The resultant coatings in different compositions and morphologies were examined by high-resolution field emission scanning electron microscopy equipped with energy-dispersive spectrometer and x-ray diffraction. The PEO-treated specimens revealed distribution of coating species, mainly the titanium-rich inner coating region. However, findings show highly localized variations in composition within their...