Thin film coatings of titanium carbide (TiC) were deposited onto carbon fibers via atmospheric pressure chemical vapor infiltration (CVI) using TiCl4, CH4, and H2 gases. Three CVI parameters were optimized to obtain high quality coatings: temperature, total gas flow rate, and H2/CH4 flow ratio. Scanning electron microscopy was used to assess the quality and morphology of the coatings, including the roughness, uniformity, fiber coverage, and fiber adhesion. The temperature was optimized to 900 °C, which yielded complete fiber coverage with minimal fiber bridging and good adhesion. Minimizing the total gas flow rate to 37.5 standard cubic centimeters per minute reduced the roughness of the TiC coating. Finally, maximizing the ratio of H2/CH4 to 4:1 was optimal for all coating qualities. Selected area electron diffraction confirmed the presence of crystalline TiC. A combination of transmission electron microscopy and fiber tow tensile testing revealed that the outer layer of carbon fiber becomes damaged by the CVI process, causing loss of strength. To circumvent this surface degradation, it is necessary to protect the fibers with a pyrolytic carbon interphase coating before depositing TiC. This method of depositing TiC onto carbon fibers proves to be competitive in terms of coating quality, deposition temperature, reaction time, and fiber strength compared to other TiC deposition methods including reactive-CVI and molten salt synthesis.

The chemical vapor infiltration technique is one of the most popular for the fabrication of the matrix portion of a ceramic matrix composite. This work focuses on tailoring an atmospheric pressure deposition of silicon carbide onto carbon fiber tows using the methyltrichlorosilane (CH3SiCl3) and H2 deposition system at atmospheric pressure to create minicomposites faster than low pressure systems. Adjustment of the flow rate of H2 bubbled through CH3SiCl3 will improve the uniformity of the deposition as well as infiltrate the substrate more completely as the flow rate is decreased. Low pressure depositions conducted at 50 Torr deposit SiC at a rate of approximately 200 nm*h−1, while the atmospheric pressure system presented has a deposition rate ranging from 750 nm*h−1 to 3.88 μm*h−1. The minicomposites fabricated in this study had approximate total porosities of 3 and 6% for 10 and 25 SCCM infiltrations, respectively.

Graphite particles modified with carbon film coating were prepared by a CVD method. Surface characteristics of carbon-coated graphite were analyzed by X-ray diffraction (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). Carbon film was uniformly coated on the graphite surface. Raman, HRTEM, and EELS studies indicated that the structures of the carbon coatings were disordered. Specific surface area of the graphite particles was decreased by carbon coating. Graphite particles coated with carbon were used as anode materials for Li-ion batteries and tested the charge/discharge ability. Uncoated graphite can only achieve 260 mAh/g specific capacity. After disordered carbon was coated onto graphite, the discharge capacity showed an increase up to 300 mAh/g. The anode can achieve a stable discharge capacity and excellent coulombic efficiency after about 60 cycles at 300 mAh/g specific capacity cutoff, and maintain a capacity cutoff of 350 mAh/g capacity without fading after another 30 cycles at a capacity cutoff of 350 mAh/g. The improvements on capacity and cyclability were due to suppression of electrolyte decomposition by the disordered carbon coated on the graphite.

Titanium nitride was deposited onto Ni, Mo and Co metal coupons by atmospheric pressure chemical vapor deposition of TiCl4/N2/H2 in the temperature range of 700 to 800 °C. As the deposition temperature increases, the crystallinity and deposition rates of the TiN coating also increased. Titanium nitride had the highest deposition rate on Ni among the metals. The morphology of the coating was also affected by the deposition temperature being more uniform and smoother at 700 °C and coarse grains started to appear at higher deposition temperatures. The TiN coating roughness is directly proportional to the surface grain size as determined by atomic force microscopy. The surface microstructures of the TiN coating on Mo and Co metal coupons coated at 700 °C consisted of irregular grains and became uneven at higher deposition temperatures.

Copper containing faujasite has been successfully prepared for the first time using a direct synthesis method. Faujasite type zeolite can be prepared in the presence of copper species by tuning the synthesis conditions. Ammonium hydroxide was used to form a copper complex that was later mixed with the reacting gel. Sodium is required to obtain copper faujasite. The complete elimination of sodium ions from the starting gel produces amorphous material. Crystallization took place at 358 K for 11 days. Crystallization temperature of 373 K produces ANA type zeolite as an impurity. Increasing by two times the amount of copper complex added to the reacting gel increases the crystallization time of Cu-FAU from 11 to 20 days (the crystallization rate decreases). The copper containing faujasite obtained was characterized by XRD, FESEM, EDX, EPR, FT-IR, TPR, and BET. According to the XRD pattern only FAU type zeolite was obtained. According to TPR experiments, the reduction temperature for Cu2+ ions present in Cu-FAU prepared by direct synthesis was 70 K more than for Cu-FAU prepared by ion-exchange. This difference can be due to the different location of the copper ions in the supercages or in the sodalite cages of the faujasite.

A simple one-pot method has been developed to deposit discreet nanometer line formations on silicon substrates without any surface pretreatment starting with vanadium pentoxide sol-gels. These vanadium suspensions were made by hydrolyzing amorphous V 2 O 5 in water. The properties of the vanadium clusters were determined through X-ray diffraction, elemental analyses, pH calculations, and concentration calculations. Morphology of the lines was examined with optical microscopy, atomic force microcoscopy, and scanning electron microscopy. Infrared spectroscopy was used to inspect the organic components. The vanadium sol-gel used formed discreet and regular lines with high reproducibility and on the same order of magnitude as other patterning techniques. Previous research with a low solubility, 8 g/L, metal oxide for line, ring, or helix formation has not been found in the literature; this work could lead to novel applications of metal oxides such as porous catalysts, battery materials, and resistive electronic materials.

Aluminum oxide and chromium oxide were deposited onto untreated and pre-oxidized Ni coupons by metal�organic chemical vapor deposition. Oxidizing the surface prior to the deposition of the ceramic coating has been studied to determine the effect of the intermediate oxide layer. The metal oxide coatings were obtained from their respective metal acetylacetonate precursors. The pyrolysis reactions were carried out under atmospheric conditions. Amorphous Al2O3 was obtained at a deposition temperature of 500 °C and crystalline Cr2O3with the corundum structure was obtained at 450 °C. The effectiveness of the metal oxide coatings as barriers were evaluated by oxidation experiments at 800 °C for 120 h. Samples coated with Al2O3 exhibited a significant decrease in oxidation rate. However, Cr2O3 coated on both untreated and pre-oxidized samples were not effective barrier coatings. Samples involving Cr2O3 deposited on untreated Ni showed an increase in oxidation rate whereas samples with Cr2O3 on heat-treated Ni showed a similar oxidation rate as uncoated Ni. The microstructures were investigated with scanning electron microscopy. Composition and crystalline structures were determined with X-ray diffraction and elemental analysis.