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Protecting Diamond Indenters for Nanoindentation Between 400-750°C Using TitaniumWeaver, Andrew S. January 2022 (has links)
The 400°C limitation to the most common nanoindenter material, diamond, is not due to diamond changing to graphite in air, which can happen above 750°C, but to the reaction of the nanoindenter with the sample, causing a change in the geometry. The nanoindentation methodology is very sensitive to a change in nanoindenter geometry, thus the typical solution for measurements above 400°C is to use a cBN nanoindenter. However, the cBN indenter that is commercially used at temperatures above 400°C is too soft for measuring hard coatings such as machine tool coatings. There is limited published research on improving nanoindentation measurements in this way. Thus, the objective of this thesis is to address whether a coated diamond could be used for nanoindentation between 400-750°C.
Due to the results of early experiments PVD titanium is the focus of this thesis as it will adhere to diamond by forming a carbide interlayer, TiC. A methodology to determine the best coating based on resistance to oxidation and robustness of the coating at temperature was used, allowing the exploration of several different titanium based alloys and coating thickness. The methodology used is as follows:
1. PVD coatings of titanium and titanium based alloys TiAl, TiN, and TiAlN were oxidized at 500, 575, and 650°C. Measurements by SEM and EDS were taken after the oxidation at each temperature. Of the coatings tested, the pure titanium coating was determined to be the best coating.
2. The coating thickness of 0.25, 0.50, and 1.0 um were evaluated with the same static oxidation test applied to the different alloys. It was determined that 0.50 um was the best thickness. A duplicate 0.50 um thick sample had a cross-section machined by FIB, and was examined by STEM, HAADF and EELS. The results confirmed that TiC was being formed at the expected rate.
3. To determine whether a coated nanoindenter could be used for measurements, a nanoindenter was first calibrated, coated by PVD with 0.50 um thick titanium, and calibrated again. The results confirmed that a coated nanoindenter could be used for performing nanoindentation measurements.
4. To determine whether the titanium PVD coating would adhere to the diamond at temperature, a coated nanoindenter was used to measure fused silicon at 450°C. After each measurement, the nanoindenter was examined by SEM and EDS. The results confirmed that the titanium coating adhered to the diamond.
This thesis demonstrates that a titanium PVD coating can protect a diamond nanoindenter during measurements between 400-750°C. The primary contributions are that coated diamond nanoindenters can be used for nanoindentation measurements, and that titanium PVD coated nanoindenters can be used for nanoindentation measurements between 400-750°C. Additional contributions include the testing of adhesion of titanium PVD coating to diamond between 400-750°C, and a methodology of evaluating coatings. / Thesis / Doctor of Philosophy (PhD)
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Experimental study of dynamic wetting in reverse-roll coatingBenkreira, Hadj January 2002 (has links)
No
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Synthesis and evaluation of novel buffer/hole-injecting oligo(9-aminoanthracene)(s) in aluminium quinolate organic electroluminescent devices (OELDs)Ganeshamurugan, Subramaniam January 2002 (has links)
No description available.
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Sol-gel processing of tellurite thin filmsWeng, Luqian January 1998 (has links)
No description available.
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Emissivity measurement of gas turbine combustor ceramic coatings and its influence on combustor designUbhi, G. S. January 1986 (has links)
No description available.
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An investigation of erosion resistant coatingsNinham, A. J. January 1985 (has links)
No description available.
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The resistance of flare stack coatings to corrosionMazraeh, Mohsen January 2001 (has links)
No description available.
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The modelling and analysis of coating processesCarter, G. C. January 1985 (has links)
No description available.
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Magnetic properties of 3.25% silicon-iron coated under tensile stressBakopoulos, C. P. January 1984 (has links)
No description available.
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Development of novel spme coatings and high-throughput automation of sample preparation for pharmaceutical and clinical samplesBreton, Francois 12 September 1901 (has links)
Increasing the efficiency of the methods used through the development and trial of novel pharmaceutical compounds is an important step to reduce the time required to develop new medical treatments. Before a drug can be used, multiple analyses are required to obtain their physical, chemical and biopharmaceutical properties. The aim of this thesis will be to show that SPME can be an advantageous technique in the field of pharmaceutical development due to its use both as a tool to determine the physical properties of drugs and to facilitate clinical development by easily and cheaply providing high-throughput analysis of compounds in biological fluids.
It will be demonstrated that a novel coating of triacontyl is capable of rapid equilibrium while providing enhanced sensitivity towards benzodiazepines when compared to shorter chain alkyl extraction phases. The same extraction phase will prove capable of providing a rapid determination of the hydrophobicity of structurally diverse β-blocker drugs while maintaining the use of solvents and analyte to a minimum. We will then show the possibility to produce large quantities of fibers using a robotic apparatus for high-throughput handling of samples. The 96 fiber plate produced will then be used to analyze the target drug loratadine in human plasma using the same apparatus.
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