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Title: A new route to high-performance functional films on polymeric web
Author: Barker, Paul Michael
ISNI:       0000 0004 2718 6124
Awarding Body: Manchester Metropolitan University
Current Institution: Manchester Metropolitan University
Date of Award: 2012
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The potential to produce coatings with enhanced properties has made high power impulse magnetron sputtering (HiPIMS) an area of great interest within the surface engineering community in recent years. Many papers and conference presentations are coming from the academic community but, at present, industry is slow to take up the technology due to known or perceived processing issues (low deposition rates, power supply instabilities, difficulties with reactive process control, etc.). Also, as yet, few applications have emerged to convince industry that this technology merits the significant investment required to move from lab-scale to production-scale processing. During this thesis a thin (>1 μm) aluminium doped zinc oxide film with a resistivity of 3.38.10-3 Ωcm has been achieved, without annealing of the coating, with low absorption of k - 3.4.10-3. A relationship between peak power and deposition rate has been explored in order to provide further understanding of the coatings produced by HiPIMS. These coatings have simultaneously been deposited onto 12 μm PET without damage to the substrate during static deposition under stable plasma conditions during coating runs of over 15 minutes. Further investigation showed that this resistivity relates to enlarged grain growth in the film and that enlarged grains may also be grown for thin films of an industrially relevant thickness, 100 nm. Further structural modifications have also been made in terms of microstructure of the films and surface roughness, when compared to films prepared by conventional methods such as direct current magnetron sputtering. Further insight into the HiPIMS process has been gained through a study of optical emission spectroscopy and hysteresis for the HiPIMS plasma and, whilst complete understanding of the process has not been attained, the complications and need for multi-parameter analysis have been put forward to aid further research in the field. To increase the understanding gained during this work, titania coatings have also been made as this material proved easy to use during experiments (the reactive zinc oxide process was prone to significant electrical arcing). This also provided a second material for use as comparison. Aluminium doped zinc oxide coatings were also produced by atomic layer deposition, again as a point of comparison to HiPIMS between two very different techniques. This thesis provides additional insight into the process control of commercially useful aluminium doped zinc oxide films to aid with the development of the process for the industrial scale. It also demonstrates that such films can be grown to an industrially relevant scale with the option to deposit these films on thin polymeric web without damage to the substrate. In this manner, the potential of the process is demonstrated although further optimisation would be required for production of the material. The commercial promise of the process is shown; an important factor for the future of HiPIMS technology.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available