• Corrosion Science and Technology
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• v.23 no.1
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• pp.41-53
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• 2024

Titanium alloy is gaining attention in the medical industry due to its excellent biocompatibility and osteoconductivity. However, the natural oxide film on the titanium surface is insoluble, resulting in inadequate bone adhesion. Therefore, it is necessary to optimize the contact between biological tissues and implant surfaces, and alter the chemical composition and morphological characteristics of the implant surface. In this study, the anodization method was applied to titanium surface treatment to form a uniform and robust oxide film. Subsequently, a chemical process, pore-widening, was employed to change the morphological characteristics of the oxide film. The concentration of the pore-widening solution was varied at 2, 4, 6, and 8 wt% and the process time was set at 30 and 60 minutes. As the concentration of the pore-widening solution increased the pore diameter of the oxide film increased. Notably, at 6 wt% for 60 minutes, the oxide film exhibited a coexistence of pillars and pores. Based on this, it was determined that surface roughness increased with higher concentration and longer process time. Additionally, the presence of pillars and pores structures maximized hydrophilicity. This study provides insights into enhancing the surface properties of titanium for improved performance in medical implants.

• Corrosion Science and Technology
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• v.20 no.5
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• pp.256-265
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• 2021

Titanium is applied in various industries due to its valuable properties and abundant reserves. Generally, if a highly uniform oxide structure and a high-density oxide film is formed on the surface through anodization treatment, the utility value such as color appearance and corrosion inhibition efficiency is further increased. The objective of this study was to determine improvement of water-repellent property by controlling titanium oxide parameters such as pore size and inter-pore distance to improve corrosion resistance. Oxide film structures of different shapes were prepared by controlling the anodization processing time and voltage. These oxide structures were then analyzed using a Field Emission Scanning Electron Microscope (FE-SEM). Afterwards, a Self-Assembled Monolayer (SAM) coating was performed for the oxide structure. The contact angle was measured to determine the relationship between the shape of the oxide film and the water-repellency. The smaller the solid fraction of the surface, the higher the water-repellent effect. The surface with excellent hydrophobic properties showed improved corrosion resistance. Such water-repellent surface has various applications. It is not only useful for corrosion prevention, but also useful for self-cleaning. In addition, a hydrophobic titanium may open up a new world of biomaterials to remove bacteria from the surface.

• Corrosion Science and Technology
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• v.22 no.3
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• pp.193-200
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• 2023

Titanium alloy (grade-4) is commonly used in industrial and medical applications. To improve its corrosion resistance and biocompatibility for medical use, it is necessary to form a titanium oxide film. In this study, the morphology of the oxide film formed by anodizing Ti-grade 4 using different electrolytes was analyzed. Wetting properties before and after surface modification with SAM coating were also observed. Electrolytes used were categorized as A, B, and C. Electrolyte A consisted of 0.3 M oxalic acid and ethylene glycol. Electrolyte B consisted of 0.1 M NH₄F and 0.1 M H₂O in ethylene glycol. Electrolyte C consisted of 0.07 M NH₄F and 1 M H₂O in ethylene glycol. Samples B and C exhibited a porous structure, while sample A formed a thickest oxide film with a droplet-like structure. AFM analysis and contact angle measurements showed that sample A with the highest roughness exhibited the best hydrophilicity. After surface modification with SAM coating, it displayed superior hydrophobicity. Despite having the thickest oxide film, sample A showed the lowest insulation resistance due to its irregular structure. On the other hand, sample C with a thick and regular porous oxide film demonstrated the highest insulation resistance.

• Korean Journal of Materials Research
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• v.17 no.1
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• pp.6-10
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• 2007

In the present study, we investigated the formation of self-organized nanostructure oxide layers on CP Ti and Ti-10Ta-10Nb alloy in an electrolyte of 1M phosphoric acid and 1.5 wt% Hydrofluoric acid. The morphology of oxide film on substrate was observed using scanning electron microscopy and transmission electron microscopy The surface roughness of titanium oxide film was analyzed by atomic force microscopy and the crystalline of specimen was investigated using X-ray diffractometer. The results of this study showed that well-aligned titanium oxide nanotubes are formed with diameter of approx. 100nm and length of approx. 500nm with CP Ti. However, it is clear that TiTaNb alloy highly irregular structure with various diameters. Transmission electron microscope investigations show that the specimens were confirmed as amorphous. Such titanium oxide nanotubes are expected a well-adhered bioacitive surface layer on titanium substrate for orthopedics and dental implants.

• Transactions on Electrical and Electronic Materials
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• v.11 no.1
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• pp.1-10
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• 2010

This is an overview paper reporting our most recent work on processing and microstructure of nano-structured oxides and their photoluminescence and photo-catalysis properties. Zinc oxide and related transition metal oxides such as vanadium pentoxide and titanium dioxide were produced by a combination of magnetron sputtering, hydrothermal growth and atmosphere controlled heat treatment. Special morphology and microstructure were created including nanorods arrays, core-brushes, nano-lollipops and multilayers with very large surface area. These structures showed special properties such as much enhanced photoluminescence and chemical reactivity. The photo-catalytic properties have also been promoted significantly. It is believed that two factors contributed to the high reactivity: the large surface area and the interaction between different oxides. The transition metal oxides with different band gaps have much enhanced photoluminescence under laser stimulation. Use of these complex oxide structures as electrodes can also improve the energy conversion efficiency of solar cells. The mixed oxide complex may provide a promising way to high-efficiency photo emitting materials and photo-catalysts.