Pulse Pressure Metal-Organic Chemical Vapour Deposition (PP-MOCVD) is a technique for creating thin coatings. It is less dependent on the volatility of precursors than other Chemical Vapour Deposition (CVD) processes as the precursors are introduced into the reaction chamber as an aerosol; therefore sublimation of the precursor is not necessary. This allows solutions of multiple compounds to be created with a known concentration and ratio of precursors. We explored the formation of hydroxyapatite (HAp) coatings for use on bone implants, using a methanolic solution of calcium lactate and trimethyl phosphate (TMP) as a PP-MOCVD precursor solution. The thermal decomposition of the precursors and the reaction between them were investigated using Thermogravimetric Analysis (TGA). Several variables on the PP-MOCVD apparatus were varied to test their effect on the formed coating: deposition temperatures, ratio of precursors, number of pulses, precursor concentration, the use of ambient temperatures and annealing the coatings after formation. All the coatings were analysed using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infra-Red spectroscopy (FTIR). These coatings were not uniformly smooth in appearance at the micro level. However, using higher deposition temperatures, an excess ratio of TMP to calcium lactate and annealing the coatings for short periods of time and low temperatures improved the uniformity of the coating. When vigorous annealing was performed it resulted in surface oxidation and the production of titanium dioxide (TiO2 ). The EDS results showed that both calcium and phosphorus were present in the coatings. The use of high deposition temperatures, excess TMP or gentle annealing resulted in calcium to phosphorous ratios similar to the stoichiometry of HAp. These same conditions gave improved coating uniformity.

Pulse Pressure Metal-Organic Chemical Vapour Deposition (PP-MOCVD) is a technique for creating thin coatings. It is less dependent on the volatility of precursors than other Chemical Vapour Deposition (CVD) processes as the precursors are introduced into the reaction chamber as an aerosol; therefore sublimation of the precursor is not necessary. This allows solutions of multiple compounds to be created with a known concentration and ratio of precursors. We explored the formation of hydroxyapatite (HAp) coatings for use on bone implants, using a methanolic solution of calcium lactate and trimethyl phosphate (TMP) as a PP-MOCVD precursor solution. The thermal decomposition of the precursors and the reaction between them were investigated using Thermogravimetric Analysis (TGA). Several variables on the PP-MOCVD apparatus were varied to test their effect on the formed coating: deposition temperatures, ratio of precursors, number of pulses, precursor concentration, the use of ambient temperatures and annealing the coatings after formation. All the coatings were analysed using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infra-Red spectroscopy (FTIR). These coatings were not uniformly smooth in appearance at the micro level. However, using higher deposition temperatures, an excess ratio of TMP to calcium lactate and annealing the coatings for short periods of time and low temperatures improved the uniformity of the coating. When vigorous annealing was performed it resulted in surface oxidation and the production of titanium dioxide (TiO2 ). The EDS results showed that both calcium and phosphorus were present in the coatings. The use of high deposition temperatures, excess TMP or gentle annealing resulted in calcium to phosphorous ratios similar to the stoichiometry of HAp. These same conditions gave improved coating uniformity.

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Hierarchical arrangement of biological composites such as nacre and bone containing high filler (ceramic) content results in high strength and toughness of the natural material. In this study we mimic the design of layered bone microstructure and fabricate an optimal multifunctional bio-nanocomposite having strength, toughness and corrosion resistance. Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer was used as a substrate material with the reinforcement of LDH (Layered double hydroxide) as a nanofiller in different concentrations to achieve enhancement in mechanical properties as well as processing related thermostability. Corrosion resistance was increased by mimicking a layered structured which incorporated a tortuous diffusion path.