The chemistry of hafnium oxide based and materials are described in the context of ion exchange and lithography. HafSOx, represented by the composition HfO₂₋[subscript x](SO₄)x, is described to possess a significant capacity towards ion exchange in acidic and basic solutions, enabling films of HafSOx to be cleanly and readily be converted to oxide films by neutralization. The optical properties, composition and morphology of these oxide films are characterized. The fabrication of mixed metal oxide films is demonstrated via solution and ion exchange routes. This thesis also explores the photoresist chemistry of HafSOx resists. A photoreaction mechanism based on the decomposition of peroxide is proposed. In addition, the patterning of HafSOx films by 193 nm, extreme ultraviolet (EUV) and electron beam radiation is described, and the influence of composition on its photoresist properties is studied. / Graduation date: 2012

Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 109-115. Also available online.

Note: / as hip and knee prosthesis, orthopaedic fixations and coronary stents. The definition of a material's biocompatibility necessitates meeting a number of criteria, including high corrosion resistance and desirable interactions of the material's surface with biological species, such as cells, platelets, and serum proteins. SSs offer acceptable resistance to uniform (general) corrosion when used as materials of construction in sorne industrial applications, which is due to the formation of a thin passive oxide film on their surface. [...] / Les aciers inoxydables (AI) 316-L sont fréquemment utilisés dans le domaine biomédical. Par exemple, nous les retrouvons dans les prothèses de hanche et de genou, dans les fixatures orthopédiques et dans les prothèse vasculaires. Pour qu'un matériel soit biocompatible, il doit avoir une résistence élevée à la corrosion. De plus, la surface du matériel doit avoir des intéractions favorables avec les différentes espèces biologiques c'est-à-dire les cellules.[...]

Thesis (Ph.D.)--University of Wollongong, 2006. / Typescript. Includes bibliographical references: leaf 252-266.

Thesis (Ph.D.)--Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.

Note:

No description available.

The aim of this project is to investigate the quality of the anodic oxide coating of twotypes of aluminium alloy samples, EN AW-6014 and EN AC-43100, and to identifyappropriate test methods to assess their corrosion resistance properties. The corrosionbehaviors of the anodic oxide coating of the selected aluminium alloys with the surfacestage as-is, anodized, and anodized & scratched are evaluated through standardizedclimate chamber tests, standardized and non-standardized immersion tests, non-standardized climatic cycle tests, and electrochemical tests. The form and extent ofcorrosion that occurs on the alloy samples after the tests are evaluated by visualappearance,surfacemorphology,andthroughcomparisonofcross-sectionalmicroscopic images of samples taken before the test. This study found that impedancetests were easy and quick test methods to check the quality of the anodic oxide layer.The study also concluded that the cyclic testing in artificial seawater and immersiontest in natural seawater at 28 ºC are the most appropriate test methods to assess thecorrosion behavior of the anodic oxide coating of aluminium alloys due to theircapability of identifying the significant differences between surface stages compared tothe pre-test samples.

Optimal precursor behavior during Chemical Vapor Deposition (CVD) is crucial for reproducible synthesis of high quality thin films. Desirable precursor properties include: 1) volatility and thermal stability at <180 °C (10 - 100 millitorr vapor pressure at atmospheric pressure) 2) low decomposition temperature (350-550 °C) to metal oxide with minimal organic ligand contamination and 3) ambient stability and minimal toxicity. Optimal selection and usage of CVD precursors is implemented by synthesis and characterization studies. Additionally, precursor synthesis and characterization studies render the development of novel precursors, which are specifically engineered for the CVD process. Lead bis-tetramethylheptadione [Pb(thd)₂], lead bis-heptafluorodimethyloctadione [Pb(fod)₂], and zirconium tetrakis-tetramethylheptadione [Zr(thd)₄], which are lead and zirconium precursors for CVD of Pb(Zr_xTi_1-x)O₃ thin films, and T8- hydridospherosiloxane, which is a silica precursor, were synthesized and purified. Free ligand was the predominant impurity from the lead and zirconium precursor syntheses, and the T8 synthesis produced several byproducts including T10-hydridospherosiloxane and a polymer. The lead and zirconium precursors were purified by recrystallization from toluene, and the T8 was purified by extracting the byproducts with pentane. Purity of Pb(thd)₂, Pb(fod)₂ and Zr(thd)₄ was confirmed by melting point determination, carbon and hydrogen elemental analysis and proton nuclear magnetic resonance spectrometry (NMR). Purity of T8 was confirmed by proton NMR. Isothermal gravimetric analysis (TGA) was used to study volatility and thermal stability of the precursors. The Zr(thd)₄ isotherms ranged from 180-260 °C, the Pb(thd)₂ and Pb(fod)₂ isotherms were 80-200 °C, and the T8 isotherms were 80-140 °C. Vapor pressure was calculated from TGA data, with use of diffusion equations. Precursors exhibited vapor pressure ranging from 0.2 - 600 millitorr, over their respective vaporization temperature ranges. Enthalpy of vaporization was calculated from Arrhenius plots of vapor pressure as a function of temperature. The Zr(thd)₄ and T8 were observed to be thermally stable over the temperature ranges and durations of experiments. The Pb(thd)₂ and Pb(fod)₂ are not thermally stable over the vaporization temperatures, and undergo oligomerization when heated at high vaporization temperatures. Addition of a polyether adduct to the lead precursor was proposed to inhibit oligomer formation at high vaporization temperatures. Precursor decomposition studies were executed in sealed quartz tubes. Products of decomposition were examined by infrared spectrometry, mass spectrometry, and solid state NMR spectrometry. Metal oxide formation from decomposition of precursors was observed at; 300-350 °C for T8, 350-550 °C for Zr(thd)₄, 250-350 °C for Pb(thd)₂, and 300 °C for Pb(fod)₂. Lead fluoride became the dominant phase of Pb(fod)₂ decomposition products above 300 °C. Intermediate decomposition products of all the precursors were documented and discussed. Synthesis and/or isolation of intermediate decomposition products of Zr(thd)₄ , Zr2O(thd)₄, was proposed as a novel precursor for ZrO₂ deposition. / Master of Science

In this research, a temperature dependent tribological investigation of selected ternary oxides was undertaken. Based on the promising results of previous studies on silver based ternary oxides, copper based ternary oxides were selected to conduct a comparative study since both copper and silver are located in the same group in the periodic table of the elements. Two methods were used to create ternary oxides: (i) solid chemical synthesis to create powders and (ii) sputtering to produce thin films. X-ray diffraction was used to explore the evolution of phases, chemical properties, and structural properties of the coatings before and after tribotesting. Scanning electron microscopy, Auger scanning nanoprobe spectroscopy, and X-ray photoelectron spectroscopy were used to investigate the chemical and morphological properties of these materials after sliding tests. These techniques revealed that chameleon coatings of copper ternary oxides produce a friction coefficient of 0.23 when wear tested at 430 °C. The low friction is due to the formation of copper tantalate phase and copper in the coatings. All sputtering coatings showed similar tribological properties up to 430 °C.