Properties of Conversion Coating of Magnesium Alloys by a Phosphate-Permanganate Solution

2005 ◽  
Vol 488-489 ◽  
pp. 665-668 ◽  
Author(s):  
Shu Sen Wu ◽  
Ming Zhao ◽  
Ji Rong Luo ◽  
You Wu Mao
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Adhesion Force ◽  
Conversion Coating ◽  
Resistance Test ◽  
Az91d Alloy ◽  
Conversion Coatings ◽  
Good Adhesion ◽  
Better Than

A chromium-free conversion coating for AZ91D magnesium alloys has been obtained by using a phosphate-permanganate solution. Examinations have been carried out on the conversion coating for morphology, composition, adhesion force and corrosion resistance. Results show that the conversion coatings are relatively uniform and continuous, with thickness from 7µm to 10µm. They exhibit good adhesion to matrix and have some non-penetrate tiny holes on the surface. The main elements of the conversion coating of AZ91D alloy are Mg、O、P、K、Al、Mn. Results of corrosion resistance test indicate that the corrosion resistance of the conversion coating by phosphate-permanganate solution is in match to that of the conversion coating formed in a chromate solution, but for the corrosion resistance after painting, the former is better than the later.

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.

Catechol/polyethyleneimine conversion coating with enhanced corrosion protection of magnesium alloys: potential applications for vascular implants

2018 ◽  
Vol 6 (43) ◽  
pp. 6936-6949 ◽  
Author(s):  
Hao Zhang ◽  
Lingxia Xie ◽  
Xiaolong Shen ◽  
Tengda Shang ◽  
Rifang Luo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Surface Modification ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Conversion Coating ◽  
Good Corrosion Resistance ◽  
Potential Applications

A catechol/polyethyleneimine conversion coating on a MgZnMn alloy possessed good corrosion resistance. Heparin was further grafted on it and this showed the potential for surface modification of magnesium-based vascular implants.

scholarly journals Improvement of bio-compatible AZ61 magnesium alloy corrosion resistance by fluoride conversion coating

2016 ◽  
Vol 60 (5) ◽  
pp. 132-138 ◽  
Author(s):  
J. Drábiková ◽  
F. Pastorek ◽  
S. Fintová ◽  
P. Doležal ◽  
J. Wasserbauer
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Simulated Body Fluid Solution ◽  
Conversion Coating ◽  
Az61 Magnesium Alloy ◽  
Wrought Magnesium Alloy ◽  
Consequent Effect ◽  
Materials Used ◽  
Short Time

Abstract Magnesium and its alloys are perspective bio-degradable materials used mainly due to their mechanical properties similar to those of mammal bones. Potential problems in utilization of magnesium alloys as bio-materials may relate to their rapid degradation which is associated with resorption problems and intensive hydrogen evolution. These problems can be eliminated by magnesium alloys surface treatment. Therefore, this work aims with analysis of the influence of fluoride conversion coating on corrosion characteristics of magnesium alloy. Unconventional technique by insertion of wrought magnesium alloy AZ61 into molten Na[BF4] salt at temperature of 450 °C at different treatment times was used for fluoride conversion coating preparation. The consequent effect of the coating on magnesium alloy corrosion was analyzed by means of linear polarization in simulated body fluid solution at 37 ± 2 °C. The obtained results prove that this method radically improve corrosion resistance of wrought AZ61magnesium alloy even in the case of short time of coating preparation.

scholarly journals Effect of Native Oxide Film on Commercial Magnesium Alloys Substrates and Carbonate Conversion Coating Growth and Corrosion Resistance

Materials ◽  
2014 ◽  
Vol 7 (4) ◽  
pp. 2534-2560 ◽  
Author(s):  
Sebastián Feliu, Jr. ◽  
Alejandro Samaniego ◽  
Elkin Bermudez ◽  
Amir El-Hadad ◽  
Irene Llorente ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Oxide Film ◽  
Magnesium Alloys ◽  
Conversion Coating ◽  
Native Oxide ◽  
Coating Growth

Structure and Corrosion Resistance of Tin Salt Conversion Coating on Aluminum Alloy

2010 ◽  
Vol 129-131 ◽  
pp. 467-471
Author(s):  
Yan Bo Wu ◽  
Si Si Zeng ◽  
Peng Sun
Keyword(s):  
Corrosion Resistance ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Spherical Particles ◽  
X Ray Diffraction ◽  
Uncoated Sample ◽  
X Ray ◽  
Coating Composition ◽  
Chemical Conversion Coating ◽  
Better Than

A chrome-free chemical conversion coating was prepared using stannous sulfate as the main salt. The morphology of the chemical conversion surface layer was observed by scanning electron microscopy (SEM). Coating composition and the microcosmic phase structure were characterized using energy dispersive X-ray (EDX) analysis and X-ray diffraction (XRD) respectively. Electrochemical method and dropping test were used to study the coatings corrosion resistance. The results indicated that the tin salts conversion coating is a crystal structure material that composites with Sn-F-O-Al et al., the surface appears as a accumulation of spherical particles, the crystallinity of conversion coating is better than uncoated sample obviously, the corrosion resistance has improved too.

scholarly journals Preparation of Degradable Superhydrophobic Mg/P/Z/F/H Composite Materials and Their Anticorrosion

2021 ◽  
Author(s):  
Zhongxian Xi ◽  
Chengqing Yuan ◽  
Xiuqin Bai ◽  
Chun Wang ◽  
Anne Neville
Keyword(s):  
Corrosion Resistance ◽  
Composite Materials ◽  
Magnesium Alloys ◽  
The Self ◽  
Heating Process ◽  
Good Adhesion ◽  
Step Method ◽  
One Step ◽  
Self Cleaning ◽  
Poly Caprolactone

In this study, the degradable superhydrophobic Mg/P/Z/F/H (magnesi-um/poly(-caprolactone)/zinc oxide/1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES)/ heating process) composite materials were prepared through one-step method for enhancing the corrosion resistance of AZ91D magnesium alloys. Electrochemical measurements showed that Mg/P/Z/F/H materials significantly improved the corrosion resistance of magnesium alloys in 3.5 wt.% NaCl. The self-cleaning, adhesion and stability tests suggested that Mg/P/Z/F/H composite materials had well self-cleaning properties, good adhesion strength and stability in wet atmosphere.

Hot Corrosion Behavior of Sputtered Fe-Y Alloy Coatings with Different Y Contents

2011 ◽  
Vol 391-392 ◽  
pp. 1263-1267
Author(s):  
Guang Yan Fu ◽  
Jing Yu Chen ◽  
Qun Liu ◽  
Yong Su
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Hot Corrosion ◽  
Alloy Coating ◽  
Good Adhesion ◽  
Corrosion Scale ◽  
Measurement Results ◽  
The Matrix ◽  
Better Than

Three Fe-Y alloy coatings with differernt kinds of Y contents were prepared on stainless steel by magnetron sputtering. The hot corrosion behavior of sputtered alloy coatings with Na2SO4 deposits at 800 °C was investigated by discontinuous weigh measurement. Results show that the sputtered Fe-Y alloy coatings exhibit good adhesion with the matrix of stainless steel, and the hot corrosion kinetic curves of the specimens approximately follow the parabolic rate law. The Fe oxides are the main substances in the corrosion scale, and the hot corrosion rate of the three Fe-Y alloy coatings increases as the Y content increases. Therefore, the hot corrosion resistance of Fe-15Y alloy coating is better than that of Fe-20Y or Fe-30Y alloy coating.

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