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A Si-Fe-Al ternary oxide-based micropowder coating was used to prevent the formation of a Zn coating on steel during the hot-dip Zn galvanizing process to reduce the welding fume and defects generated during the welding of Zn-galvanized steel. The composition ratio of the oxide powder was optimized and its microstructure and weldability were evaluated. The optimized oxide coating was stable in the hot-dip galvanizing bath at 470°C and effectively inhibited the formation of Zn coating. The Zn residue could be easily removed with simple mechanical impact. The proposed coating reduced Zn fume and prevented the residual Zn from melting in the weld bead during high-temperature welding, thus reducing the number of welding defects. The results indicated that this pretreatment can simplify the manufacturing process and shorten the process time cost-effectively.

Mg-35Zn-3Ca (wt.%) alloy containing nontoxic and biocompatible Zn and Ca as alloying elements was prepared and subjected to heat treatment and artificial aging for different duration of time to reduce its rate of degradation. Solution heat treatment was performed at 310°C while artificial aging was performed at 170°C for 0, 2.5, 5.0, 7.5, and 10.0 h and they were designated as AT0, AT1, AT2, AT3, and AT4, respectively. The finest and most homogenous reticulum was observed on the surface of the AT2 group. The result of immersion test in Hank’s balanced salt solution (HBSS) showed that the corrosion rate of the AT2 group was 2.32 mg/(cm2 day), which was significantly lower as compared to other groups P

Titanium (Ti) is often used as an orthopedic and dental implant material due to its better mechanical properties, corrosion resistance, and excellent biocompatibility. Formation of TiO2 nanotubes (TiO2 NTs) on titanium is an interesting surface modification to achieve controlled drug delivery and to promote cell growth. Carbon nanotubes (CNTs) possess excellent chemical durability and mechanical strength. The use of CNTs in biomedical applications such as scaffolds has received considerable attention in recent years. The present study aims to modify the surface of titanium by anodizing to form TiO2 NTs and subsequently deposit CNTs over it by electrophoretic deposition (EPD). Characteristic, biocompatibility, and apatite forming ability of the surface modified samples were evaluated. The results of the study reveal that CNTs coating on TiO2 nanotubes help improve the biological activity and this type of surface modification is highly suitable for biomedical applications.

Surface modification to improve the corrosion resistance and biocompatibility of the Mg-Al-Zn-Ca alloy was conducted via plasma electrolytic oxidation (PEO) in an electrolyte that included phosphate. Calcium phosphate can be easily induced on the surface of a PEO coating that includes phosphate in a physiological environment because Ca2+ ions in body fluids can be combined with PO43-. Cytotoxicity of the PEO coating formed in electrolytes with various amounts of Na3PO4 was identified. In particular, the effects that PEO films have upon oxidative stress and differentiation of osteoblast activity were studied. As the concentration of Na3PO4 in the electrolyte increased, the oxide layer was found to become thicker, which increased corrosion resistance. However, the PEO coating formed in electrolytes with over 0.2?M of added Na3PO4 exhibited more microcracks and larger pores than those formed in smaller Na3PO4 concentrations owing to a large spark discharge. A nonuniform oxide film that included more phosphate caused more cytotoxicity and oxidative stress, and overabundant phosphate content in the oxide layer interrupted the differentiation of osteoblasts. The corrosion resistance of the magnesium alloy and the thickness of the oxide layer were increased by the addition of Na3PO4 in the electrolyte for PEO treatment. However, excessive phosphate content in the oxide layer led to oxidative stress, which resulted in reduced cell viability and activity. [ABSTRACT FROM AUTHOR]

The methodology of deposition of fluoride conversion coatings is modified with the use of galvanic coupling, agitation of the electrolyte solution, and addition of K2CO3, which helps to provide a better understanding of the mechanism and new avenues to tailor the composition of the coating. A very good correlation exists between the F/O ratio of the coatings prepared under varying experimental conditions and their icorr, |Z| and phase angle maximum; the higher the F/O ratio, the better the corrosion protective ability of the coatings in Hank's balanced salt solution. The corrosion behaviour of the coatings of the present study suggests that fluoride conversion coatings show much promise for their use for biomedical applications, as long as their uniformity is improved and the composition is tailored to enrich the MgF2 phase, encompassing a higher F/O ratio. [ABSTRACT FROM AUTHOR]

Titanium (Ti) is often used as an orthopedic and dental implant material due to its better mechanical properties, corrosion resistance, and excellent biocompatibility. Formation of TiO2 nanotubes (TiO2 NTs) on titanium is an interesting surface modification to achieve controlled drug delivery and to promote cell growth. Carbon nanotubes (CNTs) possess excellent chemical durability andmechanical strength. The use ofCNTs in biomedical applications such as scaffolds has received considerable attention in recent years. The present study aims to modify the surface of titanium by anodizing to form TiO2 NTs and subsequently deposit CNTs over it by electrophoretic deposition (EPD). Characteristic, biocompatibility, and apatite forming ability of the surface modified samples were evaluated. The results of the study reveal that CNTs coating on TiO2 nanotubes help improve the biological activity and this type of surface modification is highly suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the effect of cyclic precalcification treatment to impart bioactive properties for titanium implants. Before precalcification, the titanium implants were subjected to blasting usinghydroxyapatite (HAp), a resorbable blasting medium (RBM treated), and anodized using an electrolyte containing glycerol, H2O, and NH4F. Precalcification treatment was performed by two different methods, namely, continuous immersion treatment (CIT) and alternate immersion treatment (AIT). In CIT, the RBM treated and anodized titanium implants were immersed in 0.05 M NaH2PO4 solution at 80°C and saturated Ca(OH)2 solution at 100°C for 20 min, whereas during AIT, they were immersed alternatively in both solutions for 1 min for 20 cycles. Anodizing of the titanium implants enables the formation of self-organized TiO2 nanotubes. Cyclic precalcification treatment imparts a better bioactive property and enables an increase in activation level of the titanium implants. The removal torque values of the RBM treated, CIT treated, and AIT treated titanium implants are 10.8 ± 3.7 Ncm, 17.5 Ç 3.5 Ncm, and 28.1 Ç 2.4 Ncm, respectively. The findings of the study indicate the cyclic precalcification in an effective surface treatment method that would help accelerate osseointegration and impart bioactive property of titanium implants. [ABSTRACT FROM AUTHOR]

This study examined the effects of the anodization parameters (both surfactant in electrolyte and applied voltage) on the geometrical dimensions of nanotubes. The nanotube topography, diameter, length and wall thickness were affected by the addition of a surfactant to the electrolyte and applied voltage. As a consequence, TiO2 nanotube arrays with mean tube diameters and wall thicknesses ranging from 65 to 120 nm and 20 to 28 nm, respectively, were obtained. The mean tube diameter was decreased by adding a surfactant to the electrolyte, whereas the length of the tube was increased. The nanotube diameter and length increased linearly with increasing applied potential. At 30 V, the tube to tube spacing was increased by adding a surfactant to the electrolyte. At 40 V, the tubular surface morphology collapsed completely when the electrolyte contained the surfactant but the tube length was not affected in the electrolyte without the surfactant. The TiO2 structure was dependent on the heating conditions; an amorphous and anatase phase was observed at room temperature and 500°C, respectively. The mean roughness (Ra) of the nanotube surface fabricated in the electrolyte with the surfactant was lower than that without the surfactant. [ABSTRACT FROM AUTHOR]

TiO2nanotube (TN) arrays produced by electrochemical anodization have been studied extensively in recent years as a new biomaterial for implants, drug delivery systems, immuno-isolation, biosensors, cell growth, bioartifical organs and tissue engineering. A bare TiO2nanotube implant has many weaknesses when placed in contact with biological systems and surface modification is a possible solution for this problem. The aim of this study is to develop a very simple method for surface modification of TiO2nanotubes to tailor new interfacial properties important in many biomedical applications. TiO2nanotubes were fabricated by electrochemical anodization of titanium plate using 70 wt% glycerol in deionized water with 1 wt% NH4F as an electrolyte. The lyophilization method has been applied to impregnate gelatin stabilized gold nanoparticles into the TiO2nanotubes followed by vacuum drying. This approach for tailoring different surface chemistry of TiO2nanotubes develops a new platform for biomedical applications. [ABSTRACT FROM AUTHOR]

TiO2 nanotube array (TN) on titanium plate was fabricated by using an electrochemical method. The crystal structure and surface morphology of TN array was examined by X-ray diffraction (XRD) and Field Emission Scanning Electronic Microscopy (FE-SEM), respectively. The stability of the nanotube structure and crystal phase transition was studied at different temperatures in dry oxygen ambient. The as-deposited films were found to be amorphous. The tubes crystallized in the anatase phase at a temperature of 450°C. Anatase crystallites formed inside the tubes walls was transformed completely to rutile at 500°C in dry environment. With the heating temperature increased the intensity of rutile peak increased with decrease in reflection from titanium. Intense rutile peak was observed at 600°C. The average pore diameter as calculated from FE-SEM images was 50–100 nm. At higher temperature tubular structure completely collapsed leaving dense rutile crystallites. A model was proposed to explain the formation mechanism of TN fabricated on titanium plate in HF/H2SO4 electrolyte. [ABSTRACT FROM AUTHOR]