Study on the Growth and Corrosion Resistance of Manganese Phosphate Coatings on 25Cr2Ni4WA Alloy Steel

2012 ◽  
Vol 185 ◽  
pp. 73-76
Author(s):  
J. Hu ◽  
Liang Fang ◽  
J.H. Mao ◽  
L.B. Xie ◽  
J. He ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Alloy Steel ◽  
Phosphate Coating ◽  
Polarization Method ◽  
Manganese Phosphate ◽  
Phosphate Coatings ◽  
Increase Rate ◽  
Bare Steel ◽  
Phosphated Steel ◽  
Coating Weight

The growth process and corrosion resistance of the phosphate coating on 25Cr2Ni4WA alloy steel fabricated by a high temperature manganese phosphating were investigated by XRD, SEM, EDS and electrochemical polarization method, respectively. It is found that the phosphate coating consists of lots of close packed lump crystallites and mainly composed of (Mn,Fe)5H2(PO4)4·4H2O. The coating weight increased rapidly, and then the increase rate slowed down when phosphating process was carried for about 5 min. The corrosion potentials of the phosphated steel shifted positively about 250 mV than the bare steel, indicating that the phosphating can improve the corrosion resistance of the 25Cr2Ni4WA alloy steel.

Effect of Sodium Nitrite Addition on the Corrosion Resistance of Manganese Phosphate Coating

2020 ◽  
Vol 25 (3) ◽  
pp. 43-50
Author(s):  
Kyong-Sub Min
Keyword(s):  
Corrosion Resistance ◽  
Sodium Nitrite ◽  
Coating Layer ◽  
Phosphate Coating ◽  
Nacl Solution ◽  
Cross Sectional ◽  
Manganese Phosphate ◽  
Eds Analysis ◽  
Phosphate Coatings ◽  
Main Components

This paper describes an effective metal finishing technology for obtaining manganese phosphate coatings on steel. In this study, the effect of sodium nitrite addition on the corrosion resistance of a manganese phosphate coating was investigated. The microstructure, surface morphology, and chemical composition were analyzed by FE-SEM, EDS, and XRD, while the cross-sectional images and thickness of the coating layer were analyzed by FIB. According to the results of the EDS analysis, the main components of the manganese phosphate coating were C, O, P, Mn, and Fe. The XRD results showed that (Mn,Fe)5H2(PO4)4 4H2O in the manganese phosphate coating layer was formed by a chemical reaction between manganese phosphate and elements in the underlying carbon steel. Additionally, electrochemical polarization testing was carried out in order to evaluate the corrosion protection properties of the manganese phosphate coating in a 3.5 wt.% NaCl solution. The corrosion resistance of the phosphate coating was remarkably improved by adding sodium nitrite.

scholarly journals Study on the growth and corrosion resistance of manganese phosphate coatings on 30CrMnMoTi alloy steel

2011 ◽  
Vol 18 ◽  
pp. 227-233 ◽  
Author(s):  
Liang Fang ◽  
Liang-bo Xie ◽  
Jia Hu ◽  
Yun Li ◽  
Wen-ting Zhang
Keyword(s):  
Corrosion Resistance ◽  
Alloy Steel ◽  
Manganese Phosphate ◽  
Phosphate Coatings

scholarly journals Manganese Phosphatizing Coatings: The Effects of Preparation Conditions on Surface Properties

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2585 ◽  
Author(s):  
Jakub Duszczyk ◽  
Katarzyna Siuzdak ◽  
Tomasz Klimczuk ◽  
Judyta Strychalska-Nowak ◽  
Adriana Zaleska-Medynska
Keyword(s):  
Corrosion Resistance ◽  
Polarization Resistance ◽  
Anodic Polarization ◽  
Activation Process ◽  
Phosphate Coating ◽  
Low Alloy Steel ◽  
Corrosion Properties ◽  
Guanidine Derivatives ◽  
Preparation Conditions ◽  
Manganese Phosphate

Manganese phosphate coating could be used to protect the surface of steel products. However, it is essential to determine the effects which process parameters, as well as the types of additives used, have on the efficiency of coating deposition. Thus, we present here a process of phosphatization of low-alloy steel (for 15 min at 95 °C) in manganese/nickel baths followed by a passivation process with the use of a silicon and zircon compounds. The microstructure and morphology of the surface were analyzed by SEM EDX and XRD methods. The obtained results showed that the manganese phosphate could be effectively formed at 95 °C in the solution containing nickel and guanidine derivatives. Anodic polarization of manganese coating was investigated in 0.5 M KCl by the analysis of polarization resistance. The effects of the activation process on corrosion properties of the coating have been examined. It was observed that an increased concentration of activating substances in the activation bath results in the enhancement of corrosion resistance.

scholarly journals Nano-TiO2 Phosphate Conversion Coatings – A Chemical Approach

2018 ◽  
Vol 4 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Carbon Steel ◽  
Impedance Spectroscopy ◽  
Zinc Phosphate ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Phosphate Coatings ◽  
Coating Weight

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).

Characteristics and corrosion studies of zinc–manganese phosphate coatings on magnesium–lithium alloy

RSC Advances ◽  
2014 ◽  
Vol 4 (104) ◽  
pp. 59772-59778 ◽  
Author(s):  
Guixiang Wang ◽  
Nana Cao ◽  
Yangyang Wang
Keyword(s):  
Corrosion Resistance ◽  
Conversion Coatings ◽  
Lithium Alloy ◽  
Manganese Phosphate ◽  
Phosphate Coatings ◽  
Corrosion Studies

Zinc–manganese phosphate conversion coatings have been formed on magnesium–lithium alloy, enhancing the alloy's corrosion resistance.

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

2016 ◽  
Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Carbon Steel ◽  
Zinc Phosphate ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Nano Tio2 ◽  
Phosphate Coatings ◽  
Coating Weight

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).

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

2016 ◽  
Author(s):  
Nilesh S. Bagal ◽  
Vaibhav S. Kathavate ◽  
Pravin P. Deshpande
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance Spectroscopy ◽  
Carbon Steel ◽  
Zinc Phosphate ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Nano Tio2 ◽  
Phosphate Coatings ◽  
Coating Weight

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).

Effect of Surface Roughness on Crystal Size of Manganese Phosphate Coating of Carbon Steel

2020 ◽  
Vol 20 (7) ◽  
pp. 4312-4317
Author(s):  
Ho-Young Kim ◽  
Young-Tai Noh ◽  
Jun-Hyuck Jeon ◽  
Young-Min Byoun ◽  
Ho-Sang Kang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Carbon Steel ◽  
Crystal Size ◽  
Coating Layer ◽  
Phosphate Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Manganese Phosphate ◽  
Phosphate Coatings ◽  
Effect Of Surface

In this study, the correlation between surface roughness of carbon steel and crystal size of manganese phosphate coatings has been investigated. The microstructure and surface morphology of the coatings were analyzed by SEM, XRD. The surface roughness test was carried out in order to calculate Ra value by atomic force microscopy (AFM). Also, the tribology property of manganese phosphate coating was tested by ball-on disk. XRD showed that (Mn,Fe)5H2(PO4)4·4H2O in manganese phosphate coating layer was formed by the chemical reaction between manganese phosphate and elements in carbon steel. Also, (Mn,Fe)5H2(PO4)4 · 4H2O was observed to be formed in all manganese phosphate conversion coating. With regard to the effects of surface roughness on manganese phosphate coatings, it can be seen that there is an increase of the crystal size on manganese phosphate coating as the surface roughness of carbon steel decreased. The increase of crystal size by the surface roughness had effect on the tribology property and electrochemical property. It was approved that friction coefficient of manganese phosphate coating is remarkably improved as the surface roughness of carbon steel become rough.

The influence of hexamethylenetetramine on the structure and corrosion resistance of phosphate coating on AZ31 magnesium alloy

2016 ◽  
Vol 63 (3) ◽  
pp. 161-165 ◽  
Author(s):  
Jiansan Li ◽  
Yali Li ◽  
Yanqin Chen ◽  
Jiawei Sun ◽  
Chunxiao Wang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Design Methodology ◽  
Energy Dispersive Spectrometry ◽  
Electrochemical Impedance ◽  
Phosphate Coating ◽  
X Ray Diffraction ◽  
Content Type ◽  
X Ray ◽  
Phosphate Coatings

Purpose This paper aims to report the influence of hexamethylenetetramine (HMTA) on phosphate coatings formed on AZ31 magnesium alloys. Design/methodology/approach These phosphate coatings were obtained by immersing magnesium alloys in phosphate baths with HMTA. The morphology and composition of the phosphate coatings were investigated via scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. Findings The phosphate coatings were mainly composed of CaHPO4·2H2O. The HMTA concentration in the phosphate bath influenced the crystallization and corrosion resistance of the phosphate coating. Originality/value The polarization curve shows that the anti-corrosion qualities of the phosphate coating were optimal when the HMTA concentration was 1.0 g/L in the phosphate bath. Electrochemical impedance spectroscopy (EIS) shows that the electrochemical impedances increased gradually when the HMTA concentration varied from 1.0 to 3.0 g/L.

Effect of under layer metallic coating composition on phosphating and the corrosion performance for automobile applications

CORROSION ◽  
10.5006/3748 ◽  
2021 ◽  
Author(s):  
Chandrashekhar Savant ◽  
Poorwa Gore ◽  
VS Raja
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Organic Coating ◽  
Phosphate Coating ◽  
Corrosion Performance ◽  
Epoxy Primer ◽  
Phosphate Coatings ◽  
Galvanized Coating ◽  
Salt Fog

Automobile coating system consists of a metallic underlayer followed by a phosphate coating and, lastly, multilayer organic coating. In this work, the effect of the underlying metallic coatings, namely, a Mg-Al-Zn alloy coating (Magizinc) and a conventional galvanized Zn coating on the phosphate coatings formed thereon, and its corrosion performance was investigated. The corrosion resistance offered by the phosphate coating formed on the Magizinc coating was higher than the phosphate coating on the galvanized Zn coating (a reference coating employed in the study) in NaCl solution, as revealed by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt-fog tests. In-depth characterization of the phosphate coatings was carried out using scanning electron microscopy and glow discharge optical emission spectroscopy. It was revealed that the phosphate crystals formed on the Magizinc coating were more fine-grained, compact, and crack-free as compared to that formed on the galvanized coating and contained Mg aiding 4-10 times increase in the corrosion resistance as determined by the electrochemical studies. However, it only improved marginally against the appearance of red rust in a salt-fog test over the unphosphated Magizinc coating. The phosphate coating on Magizinc marginally improved the adhesion of an epoxy primer coating applied on the phosphated Magizinc coating and significantly (>3.5 times longer exposure) retarded the deterioration of the epoxy primer coating in the salt-fog environment in comparison with the similar studies carried out on the phosphated conventional galvanized zinc coating. Notably, phosphating the Magizinc coating caused a ten times reduction in the H pickup compared to that in the galvanized coating under identical phosphating conditions, suggesting the former coating lowered the propensity for hydrogen embrittlement in the steel.

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