Limits...
Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion.

Zhang X, Wu G, Peng X, Li L, Feng H, Gao B, Huo K, Chu PK - Sci Rep (2015)

Bottom Line: A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions.Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane.The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.

ABSTRACT
Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

No MeSH data available.


Related in: MedlinePlus

Representative TEM and HR-TEM images and corresponding EDS spectrum of the microsheet.The scale bar in the inset is the same as that in the corresponding TEM image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663789&req=5

f4: Representative TEM and HR-TEM images and corresponding EDS spectrum of the microsheet.The scale bar in the inset is the same as that in the corresponding TEM image.

Mentions: Figure 4a depicts the representative TEM images of the microsheets that are composed of many single slices (inset picture) about 15 nm thickness constituting a layered structure. There are many small pits dispersed on the surface of the microsheets as shown by the HR-TEM image in Fig. 4b. The inset atomic-scale HR-TEM image of a single Mg-Al LDH slice discloses defects about 5 nm in diameter. The corresponding EDS spectrum of the microsheets shows strong signals of Mg, Al, and O (carbon signal coming from the substrate) with atomic ratios of 3:1:8.8, suggesting that the Mg-Al LDH has a chemical formula of Mg6Al2(OH)18 (Fig. 4c). The lattice spacings between adjacent planes in the microsheets are approximately 0.23 and 0.205 nm, as shown in Fig. 4d, corresponding to those between the two (015) and (107) crystal planes of Mg6Al2(OH)18, respectively. The TEM results are consistent with data obtained by XRD, FTIR and XPS confirming the formation of the layered Mg-Al LDH microsheet on the Mg alloy.


Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion.

Zhang X, Wu G, Peng X, Li L, Feng H, Gao B, Huo K, Chu PK - Sci Rep (2015)

Representative TEM and HR-TEM images and corresponding EDS spectrum of the microsheet.The scale bar in the inset is the same as that in the corresponding TEM image.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663789&req=5

f4: Representative TEM and HR-TEM images and corresponding EDS spectrum of the microsheet.The scale bar in the inset is the same as that in the corresponding TEM image.
Mentions: Figure 4a depicts the representative TEM images of the microsheets that are composed of many single slices (inset picture) about 15 nm thickness constituting a layered structure. There are many small pits dispersed on the surface of the microsheets as shown by the HR-TEM image in Fig. 4b. The inset atomic-scale HR-TEM image of a single Mg-Al LDH slice discloses defects about 5 nm in diameter. The corresponding EDS spectrum of the microsheets shows strong signals of Mg, Al, and O (carbon signal coming from the substrate) with atomic ratios of 3:1:8.8, suggesting that the Mg-Al LDH has a chemical formula of Mg6Al2(OH)18 (Fig. 4c). The lattice spacings between adjacent planes in the microsheets are approximately 0.23 and 0.205 nm, as shown in Fig. 4d, corresponding to those between the two (015) and (107) crystal planes of Mg6Al2(OH)18, respectively. The TEM results are consistent with data obtained by XRD, FTIR and XPS confirming the formation of the layered Mg-Al LDH microsheet on the Mg alloy.

Bottom Line: A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions.Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane.The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.

ABSTRACT
Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

No MeSH data available.


Related in: MedlinePlus