Novel components by magnetron sputtering

Brookes, MG 2005, Novel components by magnetron sputtering , PhD thesis, University of Salford.

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Abstract

The advent of the closed field unbalanced magnetron sputtering (CFUBMS) technique has provided a novel method for the production of ultra thick (above 50(jm) multilayer coatings, which form free standing foils when removed from the substrate. Applications for this method range from the production of complex metal/ceramic probe tips, to an alternative route for the production of axisymmetric high precision-machined components, such as a bellows component used in the production of uranium enrichment by the sponsors of this project, Urenco (Capenhurst) Ltd. In this study the CFUBMS system was developed to grow 50 Jim metallic and reactive compound multilayer foils. These foils were tested for compatibility with uranium hexafluoride, UFe , a corrosive gas used in the production of enriched uranium that is also in contact with the bellows component. Secondly the CFUBMS system was developed to grow 50umaluminium/ aluminium oxide, Al/A^Os, aluminium-magnesium/ magnesium (Al- Mg/Mg) and titanium/ titanium nitride (Ti/TiN) multilayer combinations. The Al/A^Os and Ti/TiN foils were deposited using vertically opposed magnetrons, with the A^Os and TiN layers produced by reactive sputtering. The Al-Mg/Mg foils were deposited from commercial purity Al and Mg targets in a co-planar configuration; conditions having been initially found that produced high hardness/ high strength amorphous Al-Mg alloy foils. All three multilayer systems benefit mechanically from the combination of a high strength component (ALzOs, TiN and Al-Mg) and a ductile component (Al, Ti, and Mg). Global conditions were found that limited the stresses induced in these ultra thick coatings. Experimental arrays were then constructed to investigate the effect of relative percentage volume fraction, substrate power and interlayer wavelength against the hardness, Young's modulus, tensile strength, UTS and other mechanical properties of the foils. These properties were determined using a modified Hounsfield tensometer. The study found that when in tension, the interlayer wavelength has no effect upon the tensile strength of the foil. However, as expected, tensile strength was strongly dependent upon the relative percentage volume fraction of the high strength component of the foil. The substrate power was found to have a limited influence upon mechanical properties. Conditions were found that produced a tensile strength-to-film density ratio of 238 MPa/ g cm" 3 , approaching that of tool steel.

Item Type: Thesis (PhD)
Contributors: Kelly, P (Supervisor)
Schools: Schools > School of Computing, Science and Engineering
Depositing User: Institutional Repository
Date Deposited: 30 Jul 2021 13:58
Last Modified: 27 Aug 2021 21:56
URI: http://usir.salford.ac.uk/id/eprint/61374

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