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This dissertation, Synthesis and Microstructure of NixAl1-x (0.5 X 1) Thin Films by Thangaraj Joseph Sahaya, Anand, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled Synthesis and Microstructure of Ni Al (0.5 Submitted by Thangaraj Joseph Sahaya Anand for the degree of Doctor of Philosophy at The University of Hong Kong in September 2004 Thin films have become important for basic studies in physics and in many other engineering fields. The immense interest in the basic properties of thin films is due to considerable variations in their properties compared to those of bulk materials. Intermetallic aluminides, such as NiAl and Ni Al, become candidate thin film materials for their specific high temperature strength and oxidation resistance, and may find applications in micro-electronic devices as thin film thermistors. This study attempted to synthesis Ni-Al thin films with stoichiometry of Ni Al, Ni Al, 0.5 0.5 0.65 0.35 Ni Al and Ni Al by DC magnetron sputtering technique on both conducting Ni 0.8 0.2 0.9 0.1 substrates as well as glass microslides. A substantial amount of oxygen was observed by chemical analysis to exist in -5 the Ni-Al films during deposition at high base pressure conditions (1 x 10 mbar). The oxygen content reduced by a certain level at low base pressure conditions ( 4.0 x -6 10 mbar) and after post-deposition annealing. The structure of these films was revealed by electron microscopy and found to be columnar. An expansion of the lattice by nearly 5% was observed for the Ni Al and the Ni Al films in their 0.5 0.5 0.8 0.2 low thickness as deposited state. The lattice size reaches the bulk value when the film thickness increases or after vacuum annealing heat-treatment. The Ni Al films 0.8 0.2 have a nanocrystalline structure in which the ordered L1 phase appears upon annealing at above 500C. iIn the course of assessment of the general physical properties of these alloy thin films a thermal transition was observed in Ni Al stoichiometry. We used two 0.8 0.2 different d.c.-magnetron sputter systems and the results were nearly the same. This proves that the insulator-to-metal transition is characteristic of the Ni Al alloy x 1-x system in the thin-film state. The temperature coefficient of resistance (TCR) is negative only to a narrow range of x from 0.75 to 0.8, and when x >= 0.9 or x DOI: 10.5353/th_b2953336 Subjects: Nickel-aluminum alloysThin films

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