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 Design and Multidimensional Screening of Flash-PEO Coatings for Mg in Comparison to Commercial Chromium(VI) Conversion Coating

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 337
Author(s):  
Ewa Wierzbicka ◽  
Marta Mohedano ◽  
Endzhe Matykina ◽  
Raul Arrabal
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Chromium Vi ◽  
Alkaline Electrolytes ◽  
Az31b Alloy ◽  
Plasma Electrolytic

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations demand for an expedient discovery of a Cr(VI)-free alternative corrosion protection for light alloys even though the green alternatives might never be as cheap as current harmful technologies. In the present work, flash- plasma electrolytic oxidation coatings (FPEO) with the process duration < 90 s are developed on AZ31B alloy in varied mixtures of silicate-, phosphate-, aluminate-, and fluoride-based alkaline electrolytes implementing current density and voltage limits. The overall evaluation of the coatings’ anticorrosion performance (electrochemical impedance spectroscopy (EIS), neutral salt spray test (NSST), paintability) shows that from nine optimized FPEO recipes, two (based on phosphate, fluoride, and aluminate or silicate mixtures) are found to be an adequate substitute for commercially used Cr(VI)-based conversion coating (CCC). The FPEO coatings with the best corrosion resistance consume a very low amount of energy (~1 kW h m−2 µm−1). It is also found that the lower the energy consumption of the FPEO process, the better the corrosion resistance of the resultant coating. The superb corrosion protection and a solid environmentally friendly outlook of PEO-based corrosion protection technology may facilitate the economic justification for industrial end-users of the current-consuming process as a replacement of the electroless CCC process.

Controlled release and corrosion protection by self-assembled colloidal particles electrodeposited onto magnesium alloys

2015 ◽  
Vol 3 (8) ◽  
pp. 1667-1676 ◽  
Author(s):  
Jiadi Sun ◽  
Ye Zhu ◽  
Long Meng ◽  
Wei Wei ◽  
Yang Li ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Controlled Release ◽  
Magnesium Alloys ◽  
Corrosion Protection ◽  
Colloidal Particles ◽  
Self Assembled ◽  
Bioactive Agents

Self-assembled nanoparticles loaded with bioactive agents were electrodeposited to provide the magnesium alloy with controlled release and corrosion resistance properties.

scholarly journals Preparation of Ti–Zr-Based Conversion Coating on 5052 Aluminum Alloy, and Its Corrosion Resistance and Antifouling Performance

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Hehong Zhang ◽  
Xiaofeng Zhang ◽  
Xuhui Zhao ◽  
Yuming Tang ◽  
Yu Zuo
Keyword(s):  
Corrosion Resistance ◽  
Surface Modification ◽  
Aluminum Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Salt Water ◽  
Water Immersion ◽  
Chemical Conversion ◽  
Corrosion Current ◽  
Conversion Coating

A chemical conversion coating on 5052 aluminum alloy was prepared by using K2ZrF6 and K2TiF6 as the main salts, KMnO4 as the oxidant and NaF as the accelerant. The surface morphology, structure and composition were analyzed by SEM, EDS, FT–IR and XPS. The corrosion resistance of the conversion coating was studied by salt water immersion and polarization curve analysis. The influence of fluorosilane (FAS-17) surface modification on its antifouling property was also discussed. The results showed that the prepared conversion coating mainly consisted of AlF3·3H2O, Al2O3, MnO2 and TiO2, and exhibited good corrosion resistance. Its corrosion potential in 3.5 wt % NaCl solution was positively shifted about 590 mV and the corrosion current density was dropped from 1.10 to 0.48 μA cm−2. By sealing treatment in NiF2 solution, its corrosion resistance was further improved yielding a corrosion current density drop of 0.04 μA cm−2. By fluorosilane (FAS-17) surface modification, the conversion coating became hydrophobic due to low-surface-energy groups such as CF2 and CF3, and the contact angle reached 136.8°. Moreover, by FAS-17 modification, the corrosion resistance was enhanced significantly and its corrosion rate decreased by about 25 times.

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

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.

Surface Modification on Magnesium Alloys by Coating with Magnesium Fluorides

2005 ◽  
Vol 475-479 ◽  
pp. 505-508 ◽  
Author(s):  
T. Ohse ◽  
Harushige Tsubakino ◽  
Atsushi Yamamoto
Keyword(s):  
Corrosion Resistance ◽  
Surface Modification ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Az31 Alloy ◽  
Immersion Test ◽  
Low Ph ◽  
Nacl Solution ◽  
Filiform Corrosion ◽  
A New Technique

A new technique has been developed for improving corrosion resistance on magnesium alloys. Specimens of AZ31 magnesium alloy were dipped into molten salt of NaBF4 at 723 K for various times, and then cooled, rinsed with water, and dried in air. Corrosion resistance in the surface treated specimens was evaluated by salt immersion test using 1 % NaCl solution as a time for occurring filiform corrosion. On an un-treated AZ31 alloy, the time for starting the filiform corrosion was about 1.2 ks, while on the surface treated specimen, the time was prolonged into about 1300 ks. Moreover, the surface treated specimen showed corrosion resistance in low pH solutions, such as 1 % HNO3 and HCl solutions.

Corrosion Behavior of Rare Earth Cerium Based Trivalent Chromium Conversion Coating on Zinc

2014 ◽  
Vol 881-883 ◽  
pp. 1165-1170 ◽  
Author(s):  
Shu Ting Miao ◽  
Sheng Han ◽  
Lifeng Hao
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
Rare Earth ◽  
Electrochemical Method ◽  
Trivalent Chromium ◽  
Conversion Coating ◽  
Passivation Film ◽  
Good Corrosion Resistance ◽  
Scanning Electron ◽  
Cerium Hydroxide

The present paper focused on the use of the salt of rare earth cerium as corrosion inhibitor of Zinc by using cathodic electrolytic passivation method. The corrosion resistance and the microphology of the cerium passivation film were studied by the methods of electrochemical method, scanning electron microscopy (SEM). From the results, it was shown that good corrosion resistance of cerium-based trivalent chromium conversion coating was obtained when the compositions were as follows: Ce (SO4)2, 6g/L; Cr2(SO4)3, 18.9g/L and NaNO3; current density, 2A/dm2; temperature, 40 oC; time, 60s. SEM revealed that the cerium trivalent chromium conversion coatings formed uniform cerium hydroxide and chrimuim hydroxide deposition on the surface of Zinc.

Preparation and Properties of Cerium Conversion Coatings on the Surface of Aluminum Alloy LY12

2012 ◽  
Vol 182-183 ◽  
pp. 241-244
Author(s):  
Cheng Bao Xia ◽  
Wen Jun Ge ◽  
Hou Chuan Yang
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Surface Modification ◽  
Aluminum Alloy ◽  
New Technology ◽  
Conversion Coating ◽  
Modification Technique ◽  
Resistance Performance ◽  
The Given

In order to improve the repairing quality of aircraft envelope of the aluminum alloy LY12， the cerium conversion coating technology was studied by using the surface modification technique. Principle experiment was on the basis of aviation repair technological requirement, refers to the related technique, through examination of corrosion resistance and wear resistance performance of cerium conversion coating, the principal composition of the formula for making cerium conversion coating:Ce(NO3)3 + KMnO4+ Ce-1 (chemical additive), In order to determine each composition of the formula and the technology parameters scientifically, L9(34) orthogonal testing method was adopted, and the formula of surface modification solution was optimized, the technological conditions for making cerium conversion coating on the surface of aircraft envelope were determined. Results of corrosion resistance and wear resistance of the cerium conversion coating on the surface of the aluminum alloy LY12 aircraft envelope obtained by the new technology showed: 1. On the given test conditions, the best content of each chemical composition in the formula of modification solution for making cerium conversion coating on the surface were: l.Ce(NO3)3：14g/L,KMnO4：1g/L,addictive Ce-1:0.3g/L；Main technology parameters were ：pH=1.5～2.7;temperature：20°C；time:15~25 min.；2. Under the same test condition, the corrosion resistance of surface of the cerium conversion coating obtained in test modification solution was better than Alodine 1001 obtained from Bombardier Corporation of Canada, and can meet the repairing demands of Aircraft Envelope.

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