Formation and Phase Transition of Crystalline Calcium Phosphate on Bioabsorbable Magnesium Alloy under Alkali Condition

2019 ◽  
Vol 829 ◽  
pp. 3-8
Author(s):  
Shin Watanabe ◽  
Takeshi Yabutsuka ◽  
Shigeomi Takai
Keyword(s):  
Phase Transition ◽  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Octacalcium Phosphate ◽  
Moderate Temperature ◽  
Alkali Solution ◽  
Mg Alloy ◽  
Significant Change

In order to improve the corrosion resistance, bioabsorbable magnesium (Mg) alloy was immersed in an aqueous solution with three times of Ca2+ and HPO42- in comparison with those of conventional SBF at the moderate temperature. After immersion in the solution, the whole surface of Mg alloy was coated with plate-like crystals consisting of octacalcium phosphate (OCP). Then the OCP-coated Mg alloy was immersed in the alkali solution. Although significant change of morphology was not observed, the OCP formed on the Mg alloy was transformed to hydroxyapatite (HAp) under alkali condition.

Effect of Crystalline Calcium Phosphate Coatings Prepared in an Aqueous Solution on Corrosion Resistance of Bioabsorbable Magnesium Alloy

2018 ◽  
Vol 782 ◽  
pp. 158-164
Author(s):  
Shin Watanabe ◽  
Takeshi Yabutsuka ◽  
Shigeomi Takai
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Mg Alloy ◽  
High Corrosion Resistance ◽  
Phosphate Coatings ◽  
Naoh Solution ◽  
Biological Environment ◽  
Calcium Phosphate Coatings

Bioabsorbable magnesium (Mg) alloy was anodized in 1.0 M NaOH solution. Then the anodized Mg alloy was immersed in an aqueous solution with three times concentration of Ca2+and HPO42-in comparison with those of biological environment to improve its corrosion resistance. The whole surface of Mg alloy was successfully coated with crystalline calcium phosphate (CaP) within 1 day. The CaP coated Mg alloys showed high corrosion resistance in SBF.

Biomimetic Crystalline Calcium Phosphate Coatings on Bioabsorbable Magnesium Alloy

2017 ◽  
Vol 758 ◽  
pp. 81-85 ◽  
Author(s):  
Shin Watanabe ◽  
Takeshi Yabutsuka ◽  
Shigeomi Takai
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Apatite Layer ◽  
Mg Alloy ◽  
Phosphate Coatings ◽  
Naoh Solution ◽  
Calcium Phosphate Coatings

Bioabsorbable magnesium (Mg) alloy was anodized in 1.0 M NaOH solution to improve the corrosion resistance. Then the anodized Mg alloy was immersed in an aqueous solution with three times of Ca2+ and HPO42- and lower Na+ and Cl- in comparison with those of conventional SBF. The whole surface of Mg alloy was successfully coated with plate-like apatite within 1 day. The thickness of apatite layer formed on Mg alloy was about 7 μm.

scholarly journals Effect of Al Content in the Mg-Based Alloys on the Composition and Corrosion Resistance of Composite Hydroxide Films Formed by Steam Coating

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1188 ◽  
Author(s):  
Takahiro Ishizaki ◽  
Tomohiro Miyashita ◽  
Momo Inamura ◽  
Yuma Nagashima ◽  
Ai Serizawa
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Treatment Time ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Potential Range ◽  
Protective Film ◽  
Al Content ◽  
Passive Behavior ◽  
Superior Corrosion Resistance

Mg alloys are expected to be used in fields of the transportation industry because of their lightweight property, however, they show low corrosion resistance. To improve the corrosion resistance, preparation of the protective film on Mg alloys is essential. In this study, composite hydroxide films were prepared on three types of Mg alloys with different aluminum contents—that is, AZ31, AZ61, and AZ91D—by steam coating to investigate the relationship between the Mg-Al layered double hydroxide (LDH) content in the film and the Al content in the Mg alloys. Scanning electron microscopy (SEM) observation demonstrated that films were formed densely on all Mg alloy surfaces. X-ray diffraction (XRD) analyses revealed that all films prepared on AZ61 and AZ91D were composed of Mg(OH)2, AlOOH, and Mg-Al LDH, while the film containing Mg(OH)2 and Mg-Al LDH were formed only on AZ31. The Mg-Al LDH content in the film prepared on AZ61 was relatively higher than those prepared on AZ31 and AZ91D. The content of AlOOH in the film increased with an increase in the Al content in the Mg alloys. The film thickness changed depending on the treatment time and type of Mg alloy. Polarization curve measurements in 5 mass% NaCl solution demonstrated that the film prepared on the AZ61 showed complete passive behavior within the potential range of −1.0 to −0.64 V. In addition, immersion tests in 5 mass% NaCl aqueous solution for 480 h demonstrated that the film on the AZ61 had superior durability against 5 mass% NaCl aqueous solution. These results indicated that the film on the AZ61 had the most superior corrosion resistance among all samples. The results obtained in this study suggest that the LDH content in the film could be related to the corrosion resistance of the film.

Corrosion Resistance of RE-AZ91 Magnesium Alloys

2014 ◽  
Vol 933 ◽  
pp. 66-70
Author(s):  
Jun Jie Yang ◽  
Yao Li ◽  
Ping Xue
Keyword(s):  
Tensile Strength ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Mg Alloy ◽  
Constant Voltage ◽  
High Tensile Strength ◽  
Az91 Magnesium Alloy ◽  
Az91 Magnesium ◽  
Good Heat Resistance ◽  
Good Heat

Rare Earth (RE) were added to industrial AZ91 magnesium alloy, so that RE-AZ91 Mg alloy was produced by the process of die casting, so as to study the effect of RE on corrosion resistance and tensile strength of Mg alloy. The experiment results show that RE addition could improve the tensile strength and corrosion resistance of magnesium alloy at a certain amount of RE. RE-AZ91 had a good heat resistance, corrosion resistance at a high temperature or in the environment applied constant voltage, with a high tensile strength.

Enhancing the corrosion resistance and surface bioactivity of a calcium-phosphate coating on a biodegradable AZ60 magnesium alloy via a simple fluorine post-treatment method

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56001-56010 ◽  
Author(s):  
Yingchao Su ◽  
Yanbo Lu ◽  
Yichang Su ◽  
Jiangjiang Hu ◽  
Jianshe Lian ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Treatment Method ◽  
Post Treatment ◽  
Calcium Phosphate Coating ◽  
Phosphate Coating

A simple fluorine post-treatment was attempted on a calcium-phosphate coating on an AZ60 alloy. Optimum fluorine post-treatment parameters were obtained. The fluorine post-treated coating showed improved corrosion protectiveness and surface bioactivity.

Biomimetic coating of magnesium alloy for enhanced corrosion resistance and calcium phosphate deposition

2013 ◽  
Vol 9 (10) ◽  
pp. 8650-8659 ◽  
Author(s):  
W. Cui ◽  
E. Beniash ◽  
E. Gawalt ◽  
Z. Xu ◽  
C. Sfeir
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Calcium Phosphate ◽  
Biomimetic Coating
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