Corrosion behavior of pure titanium in simulated desulfurized flue gas condensates in thermal power plant chimneys is investigated by electrochemical measurements and surface observations. Existence of fluoride ion leads to the breakdown of oxide film and promotes activation dissolution of Ti. Both anodic and cathodic reactions are enhanced by the increase of temperature, following an Arrhenius relationship. The participation of fluoride ion leads to low activation energy values. The corrosion process presents a two-step mechanism, in which dissolution of the adsorbed intermediate species is the rate determining step. Increase of temperature accelerates both of the two steps, especially the latter, and results in the low surface coverage of adsorbed species at high temperatures. Preferential dissolution occurs on specific grains and grain boundaries. Increase of temperature facilitates the crystallographic characteristics and aggravates the failure risk of the chimneys.

To develop an optimized local delivery system of simvastatin (SV) with improved osseointegration of titanium (Ti) implants, SV-loaded poly(ethylene glycol)-poly(epsilon-caprolactone) (PECL) micelles (80 nm in diameter) were loaded in titania nanotube (TNT) arrays (80-100 nm in diameter and 400 nm in length) that were fabricated by anodizing Ti sheets. An in vitro release experiment was performed and revealed that TNTs and micelles can jointly provide a sustained release of SV, and that TNTs alone might function in drug release. The effect of the Ti surface with TNTs or TNTs-micelles on osteoblast-like MG-63 cells was determined by analyzing cell morphology, cytoskeletal arrangement, early adhesion, proliferation, alkaline phosphatase activity, and intracellular and extracellular osteocalcin content. The results indicate that the Ti surface with SV-loaded TNTs-micelles not only has better able to promote early adhesion, spreading and early differentiation of osteoblasts than the Ti surface with TNTs alone but it is able to promote calcification of osteoblasts. Therefore, a Ti surface with TNTs or TNTs-micelles is expected to promote contact osteogenesis of the Ti implant, thus contributing to early osseointegration of the implant, whereas the osteogenic effect of the Ti surface with TNTs-micelles is expected to be stronger. This local delivery system can bridge the gap between basic research and applied science for a wide range of titanium-based orthopedic implants in diverse bone-loss diseases, including osteoporosis.

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Electrochemical degradation behavior of thermally oxidized pure Ti in the fluoride-containing acidic environments was investigated. Compact TiO2 oxides with acceptable hardness and superior corrosion resistance are formed through the thermal oxidation at 650 °C for 24 h. Corrosion of the oxidized Ti depends on the oxidation condition and fluoride content, resulting in the various interfacial structures at the oxide/solution and metal/solution interface. Degradation of the oxidized Ti consists of three stages during long-term immersion, while its critical fluoride concentration is increased by 1~2 orders of magnitude, attributed to the high stability of the TiO2 thermal oxides.