Showing papers by "T. M. Sridhar published in 2007"
TL;DR: In this article, an electrochemical investigation of the coatings in neutral chloride media was carried out to obtain open circuit potential (OCP) and potentiodynamic anodic polarisation behaviour in order to evaluate their corrosion resistance.
Abstract: Electrophoretic deposition (EPD) was employed to coat TiO2 and TiO2+CeO2 on AISI type 304L stainless steel (SS) to improve its corrosion resistance. Coatings were obtained by following three main steps, namely formation of a suspension of the charged TiO2 particles with addition of CeO2, deposition of the suspended particles on the electrode under the influence of a dc electric field, and sintering of the particulate deposit at 1073 K for 2 h in vacuum to form a dense and continuous film. The uniform deposits of TiO2 and TiO2+CeO2 formed on the surface shown good sintering characteristics and were characterised using X-ray diffraction (XRD) technique. The electrochemical investigation of the coatings in neutral chloride media was carried out to obtain open circuit potential (OCP) and potentiodynamic anodic polarisation behaviour in order to evaluate their corrosion resistance. The electrochemical parameters shifted towards noble direction for the TiO2 and CeO2+TiO2 coated specimens in comparison ...
8 citations
TL;DR: In this paper, the authors used FTIR to determine the bioceramic gradient phases of the crystal structure of the teeth across the crown and root region with age, and found the presence of hydroxyapatite as the major phase after sintering along with the typical hydroxyl peaks.
Abstract: Human teeth has “structure” and yet is mostly treated as material. Differentiation between material and structure is crucial to understand complex biological material such as human dentine. The aim of the present work is to determine the bioceramic gradient phases of the crystal structure of the teeth across the crown and root region with age. Around 50 samples of teeth of different age groups were collected, decontaminated and sintered at 400, 600 and 800°C. After removal of the enamel the root and crown regions were machined and characterized for their vibrational states by FTIR investigations. The studies indicate the presence of hydroxyapatite as the major phase after sintering along with the typical hydroxyl peaks. A weight loss ranging from 7 - 42 % after sintering at 400 and 800°C respectively was observed across the different age groups. A through analysis would provide us an understanding in studying the desired nature of the teeth and kinetics of tooth mineralization.
2 citations
01 Jan 2007
TL;DR: The performance in terms of biocompatibity and tissue implant fusion of the bone implants can be enhanced by coating it with collagen and silver nano particles, which prove more susceptible to reactions.
Abstract: Orthopedic, dental, and other bone implants are becoming commonplace but they are not yet trouble free. Cadaveric bone grafts are those that come from cadavers (from deceased donors) and are used the same way as the customary bone implants. The chance of rejection is very rare if treated properly before use. The results may vary on the patients due to the factors like the strength, biocompatibility and efficiency of the implant. The performance in terms of biocompatibity and tissue implant fusion of the bone implants can be enhanced by coating it with collagen and silver nano particles. The silver nano is a proven anti-microbial agent and when laid upon the treated implant as a netted layer of micrometer pore size, using 3-D printing techniques, it will allow the surrounding tissues to fuse with the implant and provide better fixability. For providing better tissue in-growth of osteocytes, a collagen and HAP layer can be strategically placed on the implant. This matrix formed results in increase of the strength of the bone and also increases the compatibility of bones from the perspective of the human body. The bones prepared in this method should show superior characteristics than the normal cadaveric bones. The work is done by comparing the characteristics of normal bone with the bone coated with the nano particles and bioceramics. The nano particles are used at the specific sites, which prove more susceptible to reactions. The mixture overall proves to be non-reactive and its long-term performance will be studied.
2 citations
TL;DR: In this paper, human humerus bones retrieved from cadavers were selected and separated in to cortical and cancellous parts, which were heat treated at different temperatures 400°C, 600°C and 800°C respectively.
Abstract: Bone is a complicated heterogeneous, viscoelastic, anisotropic material. Its properties depend on the nature of mechanical forces in addition to the location as well as the age, sex and race of the subject. Human humerus bones retrieved from cadavers were selected and separated in to cortical and cancellous parts. They were heat treated at different temperatures 400°C, 600°C and 800°C respectively to study the crystalline nature and composition of cortical and cancellous region of the humerus bone separately. Hydroxyapatite (HAP) was present as the major phase in the bone powders at 600 and 800°C with well resolved peaks along with other mineral phases of calcium phosphate. No amorphous phases were present indicating that the crystal structure of calcium phosphate compounds is present in crystalline form. FTIR studies further confirm the presence of phosphate vibrational modes of the entire bone mineral along with the presence of carbonates and hydroxyl groups.
1 citations