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.

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

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.

Synthesis and evaluation of corrosion resistance of molybdate-based conversion coatings on electroplated zinc

2010 ◽  
Vol 205 (7) ◽  
pp. 2328-2334 ◽  
Author(s):  
Dian-long Liu ◽  
Zhi-gang Yang ◽  
Zhen-qiang Wang ◽  
Chi Zhang
Keyword(s):  
Corrosion Resistance ◽  
Conversion Coatings

scholarly journals Effect of Temperature on Corrosion Resistance of Layered Double Hydroxides Conversion Coatings on Magnesium Alloys Based on a Closed-Cycle System

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1658
Author(s):  
Xiaochen Zhang ◽  
Zhijuan Yin ◽  
Bateer Buhe ◽  
Jiajie Wang ◽  
Lin Mao ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Conversion Coating ◽  
Effect Of Temperature ◽  
Conversion Coatings ◽  
Closed Cycle ◽  
Cycle System ◽  
Double Hydroxide ◽  
Double Hydroxides

The effect of temperature on the corrosion resistance of layered double hydroxide (LDH) conversion coatings on AZ91D magnesium alloy, based on a closed-cycle system, was investigated. Scanning electron microscopy (SEM), photoelectron spectroscopy (XPS), and X-ray diffractometry (GAXRD) were used to study the surface morphology, chemical composition, and phase composition of the conversion coating. The corrosion resistance of the LDH conversion coating was determined through electropotentiometric polarisation curve and hydrogen evolution and immersion tests. The results showed that the conversion coating has the highest density and a more uniform, complete, and effective corrosion resistance at 50 °C. The chemical composition of the LDH conversion coating mainly comprises C, O, Mg, and Al, and the main phase is Mg6Al2(OH)16CO3·4H2O.

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