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Solution treatment and ageing (STA) is an effective strengthening method for a þ b titanium alloys. This paper reports the effect of solution treatment and aging on the corrosion behaviour of Ti6Al-7Nb alloy in a simulated body fluid (Ringer's solution). Ti6Al-7Nb alloy is hot rolled in the a þ b field and subjected to solution treatment above and below its beta transus temperature (1283 K). The solution treated specimens are water quenched (WQ), air-cooled (AC), and furnace cooled (FC) at three different rates, and subsequently aged at 823 K for 4 h. Microstructural changes were examined using optical microscopy and phases developed were analyzed using XRD. The influence of microstructure on the corrosion performance of the alloys are discussed in detail based on the Open Circuit Potential (OCP), passive current density and area of repassivation loop values obtained from the cyclic polarization study in Ringer's solution. The passive current density was low (0.5 lA/cm 2 ) for the specimen with duplex microstructure obtained for specimen solution treated at 1223 K, air-cooled, and aged, in comparison with that for as-rolled specimen (1.5 lA/cm 2 ). The corrosion aspects resulting from various heat treatments are discussed in detail.

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This paper compares the results of the effects of a biomimetic coating and electrophoretic deposition (EPD) of hydroxyapatite (HA) on the bond strength between the bone, implant and cell compatibility of Ti-6Al-7Nb dental implants. In the biomimetic process, screw shaped implants were chemically etched and NaOH activated to form hydroxycarbonated apatite after they were soaked for six days in a solution that was five times more concentrated than regular simulated body fluid (SBF). Electrophoretic deposition was also used to obtain a uniform coating of HA on other batchs of screws. Elemental, structural and in vivo histological and biomechanical investigations were carried out on the modified surfaces of the screws. The results show that there was a faster reaction of bone towards the coated implants compared to the uncoated one. More mature bones were observed on HA coated implants and increased mechanical strength (torque value) of bone-implant interface. Higher torque was needed to remove elephoretically and biomimetically HA coated screws from its bed compared to that needed for uncoated one (55, 50?16 and 37?45 N cm respectively). Biomimetic and electrophoretic coating with a bioactive HA leads to high integration between bone and implant by increasing the bioactivity of the product and to promoting mechanical properties of the implanted screws and enhanced osseointegration during the healing period. Owing to the higher roughness and porosity of the EPD coated screws (average R a 52921¡100 nm), the bone growth was much higher than that coated biomimetically (average R a 51550¡88 nm). Out of the two methods tried to form bioactive surface, EPD yields high bone adhesion when compared to the biomimetic coating.