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The sandblasted, large-grit and acid-etched (SLA) surface is easy to be contaminated during storage and its surface chemical state is usually changed by different sterilization methods. This causes an undesirable increase in surface hydrophobicity and results in osseointegration degradation. To overcome this problem, a low temperature hydrothermal (HT) sterilization method was proposed in this study. Briefly, 4 weeks-stored pure titanium SLA specimens were sterilized using a sealed glass bottle with pure water in an autoclave set at 121 °C for 20 min. Results showed that, stored SLA specimens were superhydrophobic before and after conventional autoclaving, whereas, HT sterilization decontaminated and endowed stored SLA surface with superhydrophilicity. Osteoblast spreading was greatly enhanced, ALP expression was upgraded and bone nodule formation was obviously promoted on HT sterilized specimens compared with autoclaved ones. More bone formation around HT sterilized specimens was observed and HT sterilization increased bonding strength of implant to bone by 95% and 127% after 2 and 4 weeks of healing, respectively. The simple, feasible HT sterilization restored osseointegration of SLA implant while diminishing recontamination as much as possible. Therefore, it is proposed as a standard sterilization method for implant practitioners and researches. [ABSTRACT FROM AUTHOR]

• Hydrothermal treatment was applied to TiN coating for surface oxidation. • Anatase nanoparticle and nanolayer were formed on TiN. • Corrosion resistance of TiN was greatly enhanced even in present of fluoride ions. Titanium nitride (TiN) coating is a promising to be used on metal implant and surface oxidation by hydrothermal treatment has been proved to effectively enhance its osteoconductivity. In this study, the physicochemical properties and corrosion resistance of the TiN coating after hydrothermal treatment in distilled water were investigated. The results showed that, Anatase-type titanium oxide (TiO 2) nanoparticles formed on the TiN surface once the temperature was over 150 °C and that they formed a compact layer when the temperature increased to over 200 °C. The treatment significantly improved the wettability of TiN coating. Although surface hardness of TiN coating decreased slightly after formation of oxide layer, it could still provide enough protection for substrate. Electrochemical experiments showed that corrosion resistance of TiN was greatly improved in present of fluoride ions (F−). Immersion test for 5 weeks showed that numerous corrosion pits appeared on untreated TiN coating, whereas, the TiO 2 layer on treated TiN coating remained intact and provided good protection for the underlying TiN. This work showed that hydrothermal treatment at 200–250 °C could comprehensively improve the properties of TiN coating necessary for biological applications and it also provide a possible solution to improve corrosion resistance of hard TiN coating on metal substrates. [ABSTRACT FROM AUTHOR]

In this paper, the corrosion behavior of low alloy steel in H 2 S-saturated solution is systematically studied through immersion experiment in terms of microstructure morphology, corrosion kinetics, surface morphology, cross-sectional morphology, crystal characteristic and elemental distribution. The experimental results suggest that the corrosion rate decreased gradually with corrosion time. The corrosion products were immediately formed after the steel was immersed in corrosion solution and the structure and thickness became denser and thicker, which improved corrosion resistance. The corrosion products transformed from mackinawite, greigite and molybdenite to mackinawite, greigite, pyrrhotite and molybdenite. For the alloying elements, Cr and Mo tended to be accumulated in corrosion products compared with the steel substrate. A schematic model of corrosion process was proposed according to experimental results. [Display omitted] • The evolution process of iron sulfides on steel surface is systematically analyzed. • The style and surface morphology of iron sulfides changes with prolonging time. • A model of corrosion process of low alloy steel exposed to H 2 S solution is proposed. [ABSTRACT FROM AUTHOR]

Surface oxidation is found to improve the osseointegration of titanium nitride (TiN) coatings on implantable titanium devices; nevertheless, systematic studies on effects of oxidation are still needed. In this study, multi-arc ion plated (MAIP) titanium nitride (TiN) coating was hydrothermally oxidized in pure water and then the structural, corrosion and wear properties of the coating were studied. A dense oxide layer of 20–50 nm in thickness is formed on TiN after hydrothermal oxidation above 200 °C. The layer is composed of flat anatase particles with a length of 50–150 nm and smaller anatase nanocrystallines located on their surface. The passivation behavior of TiN becomes much stronger in simulated saliva after oxidation treatment, showing a wider passivation range, a lower corrosion current and greatly improved impedance. In addition, the open circuit potential (OCP) of oxidized TiN remains much higher than that of untreated after 50 days of immersion. Sliding friction experiments against zirconia (ZrO 2) ceramic balls show that the wear type for the untreated TiN coating involves severe plowing and deformation. In contrast, only slight plowing is found on the surface of TiN covered with a compact anatase layer; the friction coefficient decreases sharply and the wear loss decreases obviously. [Display omitted] 1. Anatase nanolayer forms on TiN coating after hydrothermal oxidation in water. 2. Hydrothermal oxidation improves corrosion resistance of TiN in artificial saliva. 3. Anatase nanolayer contributes to obvious lubrication and wear reduction. [ABSTRACT FROM AUTHOR]