Page 77 - Synthesis of Functional Nanoparticles Using an Atmospheric Pressure Microplasma Process - LiangLiang Lin
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Titanium Nitride Nanoparticles Synthesis - an Advanced Model Study towards Nitride Nanomaterial
4.3.3 Synthesis of Titanium Nitride Nanoparticles
To have a general overview of product morphology, Figure 4.4 shows representative SEM images of titanium nitride nanostructures synthesized at condition 1. Additional SEM images are provided in Appendix to give an insight to the surface morphology at various magnifications (Figure S1). Low and high magnification images indicate that coralline-like structures of different size scatter randomly in the field of view. Those structures consist of branches that presumably clustered by numerous particles. Such type of fractal growth is probably related to the ballistic aggregation mechanism of the aerosol. The resolution of employed SEM instrument was not sufficient to estimate the size of individual particles, for this purpose TEM analysis was carried out, which will be discussed below. EDX measurement is also carried out to examine their chemical composition. The EDX pattern shows the presence of Ti, N, O and C in the products, where Ti and N are the dominant elements. The C peak always exists because products are deposited on carbon tapes for characterization. O peak also appears in the spectra, indicating that particles are partly oxidized either during the reaction process or during the sample transfer process. As reported in proceeding studies, partial oxidation is a common phenomenon in TiN synthesis process, for nanoparticles are extremely reactive and titanium itself is an oxygen getter material.29,30 It is challenging to avoid oxygen and water impurities especially in the atmospheric pressure system. Another important observation is that the synthesized particles are free of chlorine contamination, suggesting that TiCl4 or other Cl-contained components have not been incorporated to the products.
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