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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Classification and analyses of of coating flows

Benkreira, Hadj, Patel, Rajnikant, Edwards, M.F., Wilkinson, W.L. January 1994 (has links)
Yes / A classification of coating flows is presented to facilitate a fundamental approach to their study. Four categories are observed: free, metered, transfer and gravure coating flows. They are all limited by free surface(s) which make their analysis difficult. Various analytical approaches have been used and these are briefly reviewed in this paper.

Simulation and design of planarizing materials and interfacial adhesion studies for step and flash imprint lithography

Lin, Michael Wayne, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Processing studies in reactive in-mold coating for thermoplastic substrates

Zuyev, Konstantin Sergeevich 30 September 2004 (has links)
No description available.

Effects of operating conditions on the surface modification of steel using a coating method of closed-type electrical discharge

Ma, Chia-nan 26 August 2009 (has links)
¡@¡@An electrical discharge coating method, which an isolated sleeve is used to form a closed space between the end surface of electrode and the workpiece so that the particles, the ions, and the pressure during the discharge process are concentrated on this space, is employed to increase the coating speed and the quality of the coating. The electrode for the cathode is made of brass, and the workpiece for the anode SKD11. They are immersed in kerosene containing W/C powder with the concentration of 50g/L. The time for the pulse-on is 25£gs and that for the pulse-off times 500£gs. The growing thickness and the quality of coating layer are investigated under the supply voltage of 50-400V, discharge coating time of 34-284s, and the gap distance of 50-300£gm. ¡@¡@Experimental results show that when the supply voltage is larger than 100V, the gap distance less than 150£gm and discharge coating time 142s, the area covered by the coating can achieve more than 90 percent of the total surface area. Moreover, the coating thickness increases with increasing gap distance and discharge coating time, but as the gap distance is larger than 150£gm, the coating thickness decreases with increasing gap distance. ¡@¡@For a special case, under the supply voltage of 200V, the gap distance of 100£gm and the discharge coating time of 142s, the coating thickness can achieve about 17£gm with little pore in the coating layer. The hardness of the coating layer can almost achieve the level of W/C hardness.

Simulation and design of planarizing materials and interfacial adhesion studies for step and flash imprint lithography

Lin, Michael Wayne, 1980- 18 September 2012 (has links)
Step and flash imprint lithography (SFIL) was developed in 1999 at The University of Texas at Austin as a high resolution, cost-effective alternative to photolithography for nanoscale patterning. Unlike current projection steppers, which are resolution limited by diffraction phenomena, SFIL tools have demonstrated patterning capability down to 20 nm, a resolution currently unattainable using traditional lithographic techniques. The combination of high resolution and low cost of ownership make SFIL a strong candidate for future semiconductor integrated circuit manufacturing. For SFIL to be viable as a high volume process, there are numerous technical issues that need to be resolved. Reverse-tone step and flash imprint lithography (SFIL-R) is a reverse tone variant of SFIL that requires the successful application of a planarizing topcoat over topography through spincoating. Photopolymerizable nonvolatile fluids are ideal topcoat materials because they planarize better than volatile fluids during spincoating and can continue to level after spincoating. Fluid mechanics analyses indicate that complete planarization using capillary force is slow. Therefore, defining the acceptable or critical degree of planarization (DOP[subscript crit]) becomes necessary. Finite difference simulation of the spincoat and post-spin leveling processes was used to determine the planarization time for various topographic and material property combinations. A new material, Si-14, was designed to have ideal planarization characteristics and satisfy SFIL-R processing requirements and was used to validate the models through profilometry and interferometry experiments. During spincoating, minimizing the spin speed generates more planar films, however, this increases the spin time. To rectify this problem, a 2-stage spincoating process -- a first step with high spin speeds to achieve the target thickness quickly and a second step with low spin speeds to improve planarization -- was proposed and experimentally demonstrated. An alternative planarization technique is to generate a reverse-conformal film coating through Marangoni-driven flow. The SFIL process requires the clean separation of a quartz template from a polymer, and the force required to create this separation must be minimized to prevent the generation of defects. Fracture mechanics analyses show that control of the polymer modulus and interfacial fracture energy is the key to minimizing the separation force. Adjusting the crosslinker concentration in the imprint formulation reduces the modulus but has no significant impact on the fracture energy. On the other hand, adding surfactants to the imprint formulation reduces both the modulus and fracture energy. The fracture energy is further decreased by using a nonreactive, liquid surfactant versus a surfactant that reacts with the polymer matrix. Angleresolved X-ray photoelectron spectroscopy (XPS) results indicate that surfactant migration is more effective with a fluorinated surface treatment compared to an untreated quartz or organic surface. However, the fluorinated surface treatment that drives the migration process degrades over multiple imprints. Based on these results, it was concluded that the use of fluorinated surfactants must be accompanied by a surface treatment that is both stable and of a similar energy or polarity to induce migration and to lower the adhesive strength. Mixed-mode fracture affects the separation force, especially if shear stresses are present. Overfilling the templatesubstrate gap causes large amounts of shear stresses during separation; however, this phenomenon can be prevented by controlling the surface energies of the imprint template and substrate. / text

Synthesis and control of microstructure, mechanical properties, and bioactivity in biphasic and preferentially oriented calcium phosphate bioceramics

Kim, Hyunbin. January 2007 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Description based on contents viewed June 22, 2007; title from title screen. Includes bibliographical references (p. 138-149).

Plasma spray coatings for polymer composites

Diccar, Unmesh Vilas 12 1900 (has links)
Thermal spray coating was studied as one of the techniques used for coating graphite reinforced polymer composites, which are extensively used in the aviation industry. These coatings were studied for improvement of surface properties such as erosion resistance, UV protection, hardness and electro magnetic shielding. NiAl (65%Ni,35%Al) intermetallic, NiAl (95%Ni,5%Al), Aluminum and Zinc coating were thermal-spray deposited using different procedures (plasma, flame, electric wire arc) onto polymer composite substrate. Two categories of coating were evaluated: Coatings with bond coat and coatings without bond coat. Different levels of pre-surface preparation for thermal spray coatings were also studied. The microstructures, micro-hardness and electrical conductivity of these coatings were determined. Effect of different parameters on coating properties like micro-hardness and electrical conductivity were studied. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering / "December 2006."

Laser cladding surface treatment for enhancement of mechanical properties /

Yang, Wen Fu. January 1900 (has links)
Thesis (MTech (Mechanical Engineering))--Peninsula Technikon, 2003. / Word processed copy. Summary in English. Includes bibliographical references (leaves 99-105). Also available online.

Preparation and characterisation of ceramic coated metals /

Kawashima, Nobuyuki. Unknown Date (has links)
Thesis (PhD)--University of South Australia, 2002.

Processing, characterization, and properties of some novel thermal barrier coatings

Jadhav, Amol D. January 2007 (has links)
Thesis (Ph. D.)--Ohio State University, 2007. / Full text release at OhioLINK's ETD Center delayed at author's request

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