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The formation of a rutile TiO2 phase in nanohydroxyapatite (nanoHAP) coated titanium metal (nanHAP–TiO2–Ti) is reported. This work is mainly carried out in order to enhance the corrosion protection performance, osseointegration and biocompatibility. The optimized potential of nanoHAP coated titanium using electrophoretic deposition (EPD) was found to be 80 V for 3 minutes. The coated samples were sintered in air at various sintering temperatures from 600 to 900 °C for 1 hour. The crystallinity, vibrational states, surface morphology and surface topography were characterized by XRD, Raman, FESEM with EDAX and AFM studies, respectively. In the present work, investigations on the corrosion behavior of sintered samples in Ringer's solution by means of electrochemical studies using open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and anodic polarization studies were carried out. The electrochemical studies exhibited an enhanced corrosion resistance behaviour of nanoHAP coated titanium sintered at 800 °C with complete rutile TiO2 phase formation. In vitro cytotoxicity studies of the coated materials were carried out by MTT assay and cell attachment with osteoblast cells. These studies revealed enhanced cell attachment and proliferation on the composite layer compared to the uncoated metal, which controlled the release of metal ions into the biological system.

The effect of nano biphasic bioceramic (NBPC) coating on 316L stainless steel (316L SS) was investigated. NBPC coatings were developed on 316L SS by electrophoretic deposition process followed by vacuum sintering. The NBPC coatings were characterised by XRD, FTIR, FESEM with EDAX and AFM studies. The electrochemical performances of the coated samples were carried out by open circuit potential-time measurements, potentiodynamic polarisation and electrochemical impedance studies in Hank’s solution. The electrochemical studies indicate that NBPC-coated samples have improved corrosion resistance and Vickers microhardness test showed enhancement in mechanical strength. Invitro studies with MC3T3-E1 osteoblast cell shows non-toxicity and high proliferation of NBPC-coated samples. These studies confirm the enhanced corrosion resistance, good mechanical strength with enhanced cell attachment and proliferation on the coated samples thus making it an ideal candidate for orthopaedic implants.

The impact of surface functionalized titanium carbide (TiC) nanoparticles on the electrochemical and mechanical properties of epoxy nanocomposite was investigated. The functional TiC nanoparticles were synthesized using pyrrole (Py) and 2-amino-5-mercapto-1,3,4-thiadiazole (AMTD) and characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), and thermogravitric analysis (TGA) techniques. The resultant novel nanocomposite coating on Mg alloy in seawater was investigated by Tafel polarization, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) studies. Electrochemical studies revealed excellent corrosion protection performance and a decreased corrosion current density for the EP-AMTD/TiC (Rc = 4861.25 kΩ.cm2 and icorr = 3.75 μA/cm2) and the EP-Py/TiC nanocomposite coated Mg alloy (Rc = 3182.71 kΩ.cm2 and icorr = 5.65 μA/cm2) in comparison with the plain epoxy coated Mg alloy (Rc = 244.67.25 kΩ.cm2 and icorr = 9.55 μA/cm2) after 60 days of immersion. The results indicated that the functional TiC nanoparticles dispersed uniformly and retarded the propagation of aggressive ions to the coating/alloy interface. SECM observations confirmed the observation of least current at the scratched area of the EP-AMTD/TiC (2.1 I/nA) and the EP-Py/TiC (4.8 I/nA) coated alloy compared to pure epoxy coating (14.9 I/nA) even after 60 d immersion in seawater. SEM observations showed that reactive TiC nanofillers are dispersed uniformly. The changes in surface morphology, phase structure and composition were analyzed using SEM/EDX and XRD techniques. It was found that the intercalation of functional TiC nanoparticles in the epoxy coatings exhibited a smooth microstructure surface producing superior corrosion protection and mechanical properties. The mechanism of corrosion protection has been proposed.

In this study, the influence of functionalized silicon carbide (SiC) nanoparticles on the electrochemical and mechanical properties of silicon carbide/epoxy nanocomposite was investigated. The reactive SiC nanoparticles were synthesized using 3-amino-1, 2, 4-triazole-5-thiol (ATT) and 2-methoxy pyridine (MP) and characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and thermogravitric analysis (TGA) techniques. The resultant novel nanocomposite coating on Cu–Ni alloy in natural seawater was investigated with the help of the Tafel polarization, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). Electrochemical studies revealed excellent corrosion protection efficiency and a decreased corrosion current density, with an optimum concentration of 2 wt% SiC nanoparticles. The results indicated that the reactive SiC nanoparticles dispersed uniformly and retarded the propagation of corrosive ions to the Cu–Ni alloy sample and coating interface through the deflected route and minimized the electron movement between the electrolyte and alloy surface. SECM observations confirmed the detection of least current at the scratched area of the coated alloy. SEM observations showed that reactive SiC nanofillers are dispersed uniformly. The changes in surface morphology, phase structure and composition were analyzed using SEM/EDX and XRD techniques. The strong attachment of the reactive SiC and epoxy resin resulted in an enhanced mechanical properties with a defectless compact film. It was found that the reinforcement of reactive SiC nanoparticles in the epoxy coatings exhibited a smooth microstructure surface producing superior corrosion protection and mechanical properties. Corrosion mechanism has been suggested based on the investigations.

Surgical management with implant devices is one of the major workable solutions as the pain has to be alleviated and patients have to resume their physical activities. The growing number of implant surgeries coupled with parallel increase in the revision surgeries of hip and knee implants has brought to focus the need to predict and understand the causes of failures of implant materials. The electrochemical and mechanical properties play a critical role in determining the lifespan of an implant. The onset of any one form of corrosion effects the mechanical properties of the implant leading to removal of the implant. The present article deals with the need for orthopaedic and dental implants, the metals and alloys currently used and their electrochemical corrosion and mechanical behaviour under in vitro conditions. Surface engineering of metals and alloys with coatings offers an ideal solution to enhance the implant performance in vivo with superior osseointegration and blood compatibility.

In this paper we discuss the evaluation of a hydroxyapatite [Ca10(PO4)6(OH)2, HAP] layer developed on titanium by electrophoretic deposition (EPD) and interlayer TiO2 formation on titanium by sintering in air at 800 °C for 1 h using electrochemical impedance (EIS) and anodic polarisation studies. The composite layer (HAP–TiO2–Ti) so formed improved the corrosion resistance and the stability of the coatings. The crystallinity, phase composition of the metal surface, HAP coatings, surface morphology and surface topography were characterized by XRD, Raman, FESEM with EDAX and AFM studies respectively. EIS investigations of the composite layer showed high polarization resistance with low capacitance values over the uncoated sample. Similarly, during anodic polarization, high corrosion potential (Ecorr) and low corrosion current density (Icorr) values were obtained for composite layers in comparison with uncoated metal. The in vitro cytotoxicity studies of the coated material were carried out by MTT assay and cell attachment with osteoblast cells. These studies revealed an enhanced cell attachment and proliferation on the composite layer when compared to uncoated metal, which controlled the release of metal ions into the biological system.