scholarly journals Nano Metal Dioxide Incorporated Conversion Phosphate Coatings—A Chemical Approach

Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande

The present study aims at deposition of zinc phosphate coatings with the incorporation of nano Titanium dioxide particles by chemical phosphating method. Zinc phosphate coatings were developed on low carbon steel by using nano TiO2 in the standard phosphating bath. The Coated low carbon steel samples were assessed for corrosion studies using electrochemical impedance spectroscopy and potentiodynamic polarisation techniques in 3.5% NaCl solution. Chemical composition of the coatings was analysed by energy dispersive X-ray spectroscopy (EDX). Significant variations in the coating weight, porosity and corrosion resistance were observed with the addition of nano TiO2 in the phosphating bath. Corrosion rate of nano TiO2 incorporated chemical phosphate coated samples was found to be 3.5 mpy which was 4 times less than the bare uncoated low carbon steel (~14 mpy). Electrochemical impedance spectroscopy studies revels in the reduction of porosity in nano TiO2 phosphate coated samples. It was found that nano TiO2 particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal phosphating bath).

Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande

The present study aims at deposition of zinc phosphate coatings with the incorporation of nano Titanium dioxide particles by chemical phosphating method. Zinc phosphate coatings were developed on low carbon steel by using nano TiO2 in the standard phosphating bath. The Coated low carbon steel samples were assessed for corrosion studies using electrochemical impedance spectroscopy and potentiodynamic polarisation techniques in 3.5% NaCl solution. Chemical composition of the coatings was analysed by energy dispersive X-ray spectroscopy (EDX). Significant variations in the coating weight, porosity and corrosion resistance were observed with the addition of nano TiO2 in the phosphating bath. Corrosion rate of nano TiO2 incorporated chemical phosphate coated samples was found to be 3.5 mpy which was 4 times less than the bare uncoated low carbon steel (~14 mpy). Electrochemical impedance spectroscopy studies revels in the reduction of porosity in nano TiO2 phosphate coated samples. It was found that nano TiO2 particles in the phosphating solution yielded phosphate coatings of higher coating weight, greater surface coverage and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal phosphating bath).


2018 ◽  
Vol 4 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande

AbstractThe present study aims at deposition of zinc phosphate coatings on low carbon steel with incorporated nano- TiO2 particles by chemical phosphating method. The coated low carbon steel samples were assessed in corrosion studies using electrochemical impedance spectroscopy and potentiodynamic polarization techniques (Tafel) in 3.5% NaCl solution. Morphology and chemical composition of the coatings were analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy in order to observe growth of coating. Significant variations in the coating weight, porosity and corrosion resistance were observed with the addition of nano- TiO2 in the phosphating bath. Corrosion rate of nano-TiO2 chemical phosphate coated samples was found to be 3.5 milli inches per year which was 3 times less than the normal phosphate-coated sample (8 mpy). Electrochemical impedance spectroscopy studies reveal reduction of porosity of nano-TiO2 phosphate coated samples. It was found that nano-TiO2 particles in the phosphating solution yielded uniform phosphate coatings of higher coating weight, fewer defects and enhanced corrosion resistance than the normal zinc phosphate coatings (developed using normal phosphating bath).


2019 ◽  
Vol 37 (6) ◽  
pp. 565-578 ◽  
Author(s):  
Vaibhav S. Kathavate ◽  
Nilesh S. Bagal ◽  
Pravin P. Deshpande

AbstractThe efficacy of nano-TiO2-containing zinc phosphate coatings on low-carbon steel is investigated. Zinc phosphate coatings are electrodeposited on low-carbon steel (AISI 1015) keeping current density, deposition time and wt % nano-TiO2 at their respective levels. Corrosion protection performance of these coatings was assessed using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in 3.5% NaCl electrolyte. The morphology, the composition and the growth process of the zinc phosphate coating is investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, X-ray diffraction (XRD) and electrochemical measurements. The XRD study reveals that the obtained phosphate layer contains traces of hopeite and phosphophylite. The formed zinc phosphate coating offers high corrosion protection in 3.5% NaCl solution, which is well supported by EIS studies. The presence of nano-TiO2 in the phosphate bath anticipated to offer a better surface coverage and reduction in porosity and forms more homogeneous coating, which is in agreement with the SEM studies. The optimization of the electrodeposition phosphating process for achieving better responses in terms of corrosion rate and coating resistance is addressed in this paper.


2013 ◽  
Vol 686 ◽  
pp. 244-249 ◽  
Author(s):  
Poovarasi Balan ◽  
Aaron Ng ◽  
Chee Beng Siang ◽  
R.K. Singh Raman ◽  
Eng Seng Chan

Chromium pre-treatments of metal have been replaced by silane pre-treatments as more environmental friendly option. Nanoparticles can be added in the silane sol-gel network have been reported to improve corrosion resistance. In this work, the electrochemical corrosion resistance of low carbon steel coated with hybrid organic-inorganic sol-gel film filled with nanoparticles was evaluated. The sol-gel films have been synthesized from 3-glycidoxy-propyl-trimethoxy-silane (3-GPTMS) and tetra-ethyl-ortho-silicate (TEOS) precursors. These films have been impregnated with 300 ppm of silica or alumina nanoparticles. The electrochemical behavior of the coated steel was evaluated by means of electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Equivalent circuit modeling, used for quantifying the EIS measurements showed that sol-gel films containing silica nanoparticles improved the barrier properties of the silane coating. The silica nanoparticle-containing films showed highest initial pore resistance over the five days of immersion in 0.05M NaCl.


2020 ◽  
Vol 1012 ◽  
pp. 401-406
Author(s):  
Carlos Trivellato de Carvalho Filho ◽  
Pedro Paiva Brito

In the present work, the friction surfacing process was applied to manufacture aluminum alloy (AA6351) coatings on low carbon steel (AISI 1020) substrates. After friction surfacing the AA6351 deposited coatings were submitted to two finishing process in order to adjust surface roughness: milling and milling followed by sanding. The corrosion behavior of the two finishing process was compared with the as-deposited condition in order to determine the influence of surface roughness on the corrosion resistance of friction surfacing coatings. The corrosion behavior was examined by electrochemical impedance spectroscopy and potentiodynamic polarization in a 3.5wt.%NaCl solution containing naturally dissolved O2. The results obtained indicated that the elevated surface roughness observed in the as-deposited condition led to relatively lower corrosion resistance in comparison, with lower values for polarization resistance and more anodic corrosion potential.


2014 ◽  
Vol 223 ◽  
pp. 110-118 ◽  
Author(s):  
Ewa Kasprzycka

Diffusion layers produced on low-carbon steel and iron surfaces by means of vacuum titanizing process have been studied. A new technological process combining a vacuum titanizing with a preliminary electrolytic deposition of cobalt has been proposed to increase the corrosion resistance of layers. As a result, diffusion duplex layers of a Ti+Co type on the low-carbon steel and iron surfaces have been obtained. The layers microstructure, their thickness, phase composition and concentration depth profiles of elements in the diffusion zone of these layers have been investigated. Microstructure studies of these layers were performed by metallographic microscopy, X-ray diffraction, and a SEM electron microscope with a BSE and an EDS spectrometer. In addition, the layers hardness and their corrosion resistance have been determined. Corrosion measurements were performed in 0.1 M H2SO4 by means of potentiodynamic polarization and electrochemical impedance tests. The highest corrosion resistance was observed for steel samples with the Ti+Co type duplex layers, which showed the least passive current density and the highest charge transfer resistance, whereas the titanized layers, and the steel without any layer, corroded actively.


Alloy Digest ◽  
1968 ◽  
Vol 17 (8) ◽  

Abstract B and W IRON is a thoroughly killed, low carbon steel having a combination of ductility, toughness and high magnetic permeability. It is recommended for applications where good magnetic characteristics are of primary significance, such as in the manufacture of electric motor and generator housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Fe-35. Producer or source: Babcock & Wilcox Company.


Alloy Digest ◽  
1987 ◽  
Vol 36 (2) ◽  

Abstract SAE 1020 is a low-carbon steel combining good machinability, workability and weldability. It is carburized for use in case-hardened components and it is used for a wide range of applications in the hot-worked, cold-worked, normalized or quenched-and-tempered conditions. Its many uses include bolts, rods, plate applications, machinery components, case-hardened parts, spinning tools and trimming dies. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low temperature performance and corrosion resistance as well as heat treating, machining, joining, and surface treatment. Filing Code: CS-113. Producer or source: Carbon steel mills.


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