No description available.

No description available.

No description available.

The non-destructive study and characterisation of thin films and their interfaces, on an atomic scale, is a crucially important area of study in many areas of science and technology. In this thesis both high angle and grazing incidence x-ray scattering techniques have been used to study the effect of depositing thin films on surfaces with a periodic roughness, as well as studying the structure of laterally modulated surfaces themselves. High angle diffraction measurements of the out-of-plane size of Co crystallites and the crystalline texture of the Ag lattice, in a series of CoAg granular fihns, has allowed a consistent growth mechanism for the Co grains to be deduced. In grazing incidence scattering studies of this series of thin, granular films it was observed that the diffuse scatter was offset from the specular condition and the position of this offset was seen to vary, sinusoidally, upon rotation of the sample. This led to the conclusion that the growth techniques employed had caused a regular step-bunching of the Si (111) substrate. As step-bunching of surfaces can affect greatly the properties of thin films deposited on them, the ability to characterise the substrate after growth is extremely important. In spin-valves deposited on rough, tiled, silicon oxide substrates, the presence of strong interference fringes in the off-specular scatter demonstrated that vertically conformal roughness dominated the system and this was seen to result in the degradation of the magnetic sensitivity of the samples. Conversely, an enhancement in the photoluminescence from thin polymer films deposited on laterally modulated substrates led to a series of studies being made on such structures. In order to obtain information on the lateral period of such structures, as well as their roughness and thickness, existing scattering theories have been modified and a semi-kinematical code of the coherent scatter has been developed.

No description available.

The growth of thrust and improved aeroengine efficiency has been gained by increased temperatures throughout the engine. This has been achieved by improved material technology and the continuous cooling of components complemented by the addition of thermal barrier coatings (TBC) to turbine and combustion chamber components. The aggressive nature of the application process of the TBC has previously made the measurement of metal surface temperature and strain exceedingly difficult on components to which it is applied. In the present study magnetron sputter-deposited thin film sensor techniques have been developed specifically for compressor and turbine applications of noble metal thermocouples and strain gauges. The deposition, patterning and evaluation of reactively sputtered aluminium oxide, type R platinum thermocouples as well as PdCr and PtW dynamic strain gauges is reported. A sputtered NiCoCrAlY coating has been developed to replace the vacuum plasma spray process currently used in the TBC system. The most favourable location for the thin film sensor is at the metal/ceramic interface of the TBC system. However, in order to protect the sensor from the aggressive TBC process, the sensor has been deposited in a novel installation between two layers of NiCoCrAlY bond coat. Several trials have been performed to fabricate this package on turbine blade material substrates. This work has demonstrated that the proposed sensor structure is feasible. However there are problems with delamination due to contamination and residual stress and with poor electrical insulation and these have limited the high temperature testing that could be performed. The novel techniques developed are already being utilised in measurement applications on components without TBCs. This work has been performed in an industrial context. The extensive project and risk management activities are reported.

Made available in DSpace on 2014-10-09T12:23:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:36Z (GMT). No. of bitstreams: 1 00617.pdf: 4446323 bytes, checksum: 2472e6b6e02afc6e4ba94b64e17ccf87 (MD5) / Tese (Doutoramento) / IEA/T / Faculdade de Medicina, Universidade de Sao Paulo - FM/USP

Made available in DSpace on 2014-10-09T12:50:38Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:58:41Z (GMT). No. of bitstreams: 1 00830.pdf: 1838856 bytes, checksum: 0f6a3f75b210d4e73e342ebf7544cc17 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP

Made available in DSpace on 2014-10-09T12:23:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:29Z (GMT). No. of bitstreams: 1 00616.pdf: 2955306 bytes, checksum: 7bc550bfff49523b2f1142c0e3a6556c (MD5) / Tese (Doutoramento) / IEA/T / Universidade Estadual de Campinas - UNICAMP/SP

Made available in DSpace on 2014-10-09T12:30:08Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:06Z (GMT). No. of bitstreams: 1 00373.pdf: 1796905 bytes, checksum: 6355b89cc4907b0f691cdfa33e5172a1 (MD5) / Dissertacao (Mestrado) / IEA/D / Escola Politecnica, Universidade de Sao Paulo - POLI/USP