2,410 Matching Results

Search Results

Advanced search parameters have been applied.

Limited tests of molybdenum coated with molybdenum disilicide in a supersonic heated-air jet and brief description of the coating facility

Description: Report presenting a laboratory-scale vapor-deposition coating facility used in the field of high-temperature coatings. The vapor-deposition coatings were produced by the hydrogen reduction of halides and not by vacuum plating methods. The coated model was found to reach equilibrium temperature of about 3100 degrees Fahrenheit and was undamaged after 470 seconds at equilibrium temperature, while an uncoated model was destroyed in less than 6 seconds.
Date: January 9, 1958
Creator: Fields, E. M. & Wakelyn, N. T.
Partner: UNT Libraries Government Documents Department

Comparison of theoretically and experimentally determined effects of oxide coatings supplied by fuel additives on uncooled turbine-blade temperature during transient turbojet-engine operation

Description: From Summary: "An analysis was made to permit the calculation of the effectiveness of oxide coatings in retarding the transient heat flow into turbine blades when the combustion gas temperature of a turbojet engine is suddenly changed. The analysis is checked with experimental data obtained from a turbojet engine whose blades were coated with two different coating materials (silicon dioxide and boric oxide) by adding silicone oil and tributyl borate to the engine fuel. The very thin coatings (approximately 0.001 in.) that formed on the blades produced a negligible effect on the turbine-blade transient temperature response. With the analysis discussed here, it was possible to predict the turbine rotor-blade temperature response with a maximum error of 40 F."
Date: March 30, 1953
Creator: Schafer, Louis J., Jr.; Stepka, Francis S. & Brown, W. Byron
Partner: UNT Libraries Government Documents Department

Carbide coatings on graphite

Description: From abstract: "A Method has been developed for the uniform coating of graphite tubes with carbides of niobium, tantalum, and zirconium by thermal composition of their respective halide vapors."
Date: 1957
Creator: Blocher, J. M., Jr.; Ish, Carl J.; Leiter, Don P.; Plock, Layne F. & Campbell, Ivor E.
Partner: UNT Libraries Government Documents Department

The nickel dip : a radioisotope study of metallic deposits in porcelain enameling

Description: Report discussing the use of radioisotope tracer techniques to study the following phenomena: the effect of nickel dip on the deposition of cobalt metal during firing of a cobalt-bearing ground coat, the effect of surface pretreatment on the amount and distribution of nickel deposited from nickel dip on enameling iron, and the effect of application and firing of cobalt-free and cobalt-bearing enamels on the chemical form and physical distribution of nickel previously deposited on enameling iron by the nickel dip.
Date: February 1956
Creator: Richmond, Joseph C.; Kirkpatrick, Harry B. & Harrison, William N.
Partner: UNT Libraries Government Documents Department

Studies of high-temperature protection of a titanium-carbide ceramal by chromium-type ceramic-metal coatings

Description: Report presenting an investigation to gain information concerning the durability of metallic coatings as affected by frit content, firing temperature, firing time, and number of coats. Four coatings of various frit content were prepared and applied to ceramals containing 80 percent chromium and 20 percent cobalt and heated at four different temperatures.
Date: June 1951
Creator: Moore, Dwight G.; Benner, Stanley G. & Harrison, William N.
Partner: UNT Libraries Government Documents Department

Relative importance of various sources of defect-producing hydrogen introduced into steel during application of vitreous coatings

Description: "When porcelain enamels or vitreous-type ceramic coatings are applied to ferrous metals, there is believed to be an evolution of hydrogen gas both during and after the firing operation. At elevated temperatures rapid evolution may result in blistering while if hydrogen becomes trapped in the steel during the rapid cooling following the firing operation gas pressures may be generated at the coating-metal interface and flakes of the coating literally blown off the metal. To determine experimentally the relative importance of the principal sources of the hydrogen causing the defects, a procedure was devised in which heavy hydrogen (deuterium) was substituted in turn for regular hydrogen in each of five possible hydrogen-producing operations in the coating process" (p. 269).
Date: July 12, 1951
Creator: Moore, Dwight G.; Mason, Mary A. & Harrison, William N.
Partner: UNT Libraries Government Documents Department

Relative importance of various sources of defect-producing hydrogen introduced into steel during application of vitreous coatings

Description: Report presenting a study in which heavy hydrogen (deuterium) was substituted in turn for regular hydrogen in each of five possible hydrogen-producing operations in the coating process. The gas that evolved when coated steel specimens fishscaled after firing was collected and analyzed with the mass spectrometer.
Date: February 1952
Creator: Moore, Dwight G.; Mason, Mary A. & Harrison, William N.
Partner: UNT Libraries Government Documents Department

Measured energy savings from the application of reflective roofsin 2 small non-residential buildings

Description: Energy use and environmental parameters were monitored in two small (14.9 m{sup 2}) non-residential buildings during the summer of 2000. The buildings were initially monitored for about 1 1/2 months to establish a base condition. The roofs of the buildings were then painted with a white coating and the monitoring was continued. The original solar reflectivities of the roofs were about 26%; after the application of roof coatings the reflectivities increased to about 72%. The monitored electricity savings were about 0.5kWh per day (33 Wh/m2 per day). The estimated annual savings are about 125kWh per year (8.4 kWh/m2); at a cost of $0.1/kWh, savings are about $0.86/m2 per year. Obviously, it costs significantly more than this amount to coat the roofs with reflective coating, particularly because of the remote locations of these buildings. However, since the prefabricated roofs are already painted green at the factory, painting them a white (reflective) color would bring no additional cost. Hence, a reflective roof saves energy at no incremental cost.
Date: January 14, 2003
Creator: Akbari, Hashem
Partner: UNT Libraries Government Documents Department

TEM Studies of Carbon Coated LiFePO4 after Charge DischargeCycling

Description: Carbon coating has proven to be a successful approach toimprove the rate capability of LiFePO4 used in rechargeable Li-ionbatteries. Investigations of the microstructure of carbon coated LiFePO4after charge discharge cycling shows that the carbon surface layerremains intact over 100 cycles. We find micro cracks in the cycledmaterial that extend parallel to low indexed lattice planes. Ourobservations differ from observations made by other authors. However thedifferences between the orientations of crack surfaces in both studiescan be reconciled considering the location of weak bonds in the unit celland specimen geometry as well as elastic stress fields ofdislocation.
Date: November 30, 2006
Creator: Gabrisch, H.; Wilcox, J. & Doeff, M.
Partner: UNT Libraries Government Documents Department

Effect of sliding velocity on friction properties and endurance life of bonded lead monoxide coatings at temperatures up to 1250 degrees F

Description: Report presenting studies to determine the effect of sliding velocity and ambient temperature on the friction properties and endurance lift of thin lead monoxide coatings bonded to type 440-C martensitic stainless steel. Results regarding the effect of run-in on endurance life are also provided.
Date: May 16, 1958
Creator: Sliney, Harold E.
Partner: UNT Libraries Government Documents Department

High Density Infrared (HDI) Transient Liquid Coatings for Improved Wear and Corrosion Resistance

Description: This report documents a collaborative effort between Oak Ridge National Laboratory (ORNL), Materials Resources International and an industry team of participants to develop, evaluate and understand how high density infrared heating technology could be used to improve infiltrated carbide wear coatings and/or to densify sprayed coatings. The research included HDI fusion evaluations of infiltrated carbide suspensions such (BrazeCoatĀ® S), composite suspensions with tool steel powders, thermally sprayed Ni-Cr- B-Si (self fluxing alloy) and nickel powder layers. The applied work developed practical HDI / transient liquid coating (TLC) procedures on test plates that demonstrated the ability to fuse carbide coatings for industrial applications such as agricultural blades, construction and mining vehicles. Fundamental studies helped create process models that led to improved process understanding and control. The coating of agricultural blades was demonstrated and showed the HDI process to have the ability to fuse industrial scale components. Sliding and brasive wear tests showed that high degree of wear resistance could be achieved with the addition of tool steel powders to carbide particulate composites.
Date: July 5, 2007
Creator: Smith, Ronald W.
Partner: UNT Libraries Government Documents Department

Progress in Large Period Multilayer Coatings for High Harmonic and Solar Applications

Description: Multilayer coatings for normal incidence optics designed for the long wavelength region (25 nm < {lambda} < 50 nm) are particularly challenging due to the few number of layers that can be utilized in the reflection. Recently, Mg/SiC multilayers have been fabricated with normal incidence reflectivity in the vicinity of 40% for wavelengths near the He-II line at 30.4 nm. Motivated by this success we have investigated the use of a tri-band multilayer to increase the bandwidth while maintaining the reflectivity. The multilayers were deposited by conventional magnetron sputtering. Using Mg/SiC bilayers a reflectivity of 45% was achieved at 27 to 32 nm at an angle of 5 deg from normal. The Mg/Sc/SiC multilayer systems have also been investigated. It obtained a near normal incidence reflectivity of 35% while increasing the bandwidth by a factor of 2. These results are very encouraging for the possibility of more widespread applications of normal incidence optics in high harmonic applications.
Date: January 7, 2008
Creator: Jones, Juanita; Aquila, Andrew; Salmassi, Farhad & Gullikson, Eric
Partner: UNT Libraries Government Documents Department

Electrodeposited Metal Matrix Composites for Enhanced Corrosion Protection and Mechanical Properties

Description: In the oil and gas industry, high corrosion resistance and hardness are needed to extend the lifetime of the coatings due to exposure to high stress and salt environments. Electrodeposition has become a favorable technique in synthesizing coatings because of low cost, convenience, and the ability to work at low temperatures. Electrodeposition of metal matrix composites has become popular for enhanced corrosion resistance and hardness in the oil and gas industry because of the major problems that persist with corrosion. Two major alloys of copper-nickel, 90-10 and 70-30, were evaluated for microbial corrosion protection in marine environments on a stainless steel substrate. Copper and copper alloys are commonly used in marine environments to resist biofouling of materials by inhibiting microbial growth. Literature surveying the electrodeposition of Cu-Ni incorporated with nano- to micro- particles to produce metal matrix composites has been reviewed. Also, a novel flow cell design for the enhanced deposition of metal matrix composites was examined to obtain the optimal oriented structure of the layered silicates in the metal matrix. With the addition of montmorillonite into the Ni and Cu-Ni matrix, an increase in strength, adhesion, wear and fracture toughness of the coating occurs, which leads to an increase corrosion resistance and longevity of the coating. These coatings were evaluated for composition and corrosion using many different types of instrumental and electrochemical techniques. The overall corrosion resistance and mechanical properties were improved with the composite films in comparison to the pure metals, which proves to be advantageous for many economic sectors including the oil and gas industry.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: May 2016
Creator: Thurber, Casey Ray
Partner: UNT Libraries

Bioinspired and biocompatible coatings of poly(butylene adipate-co-terephthalate) and layer double hydroxide composites for corrosion resistance

Description: Hierarchical arrangement of biological composites such as nacre and bone containing high filler (ceramic) content results in high strength and toughness of the natural material. In this study we mimic the design of layered bone microstructure and fabricate an optimal multifunctional bio-nanocomposite having strength, toughness and corrosion resistance. Poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer was used as a substrate material with the reinforcement of LDH (Layered double hydroxide) as a nanofiller in different concentrations to achieve enhancement in mechanical properties as well as processing related thermostability. Corrosion resistance was increased by mimicking a layered structured which incorporated a tortuous diffusion path.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: May 2016
Creator: Rizvi, Syed Hussain
Partner: UNT Libraries

Spin-on-glass coatings for the generation of super-polishedsubstrates for extreme ultraviolet optics

Description: Substrates intended for use as extreme ultraviolet (EUV) optics have extremely stringent requirements in terms of finish. These requirements can dramatically increase the cost and fabrication time, especially when non-conventional shapes, such as toroids, are required. Here we present a spin-on-glass resist process capable of generating super-polished parts from inexpensive substrates. The method has been used to render diamond-turned substrates compatible for use as EUV optics. Toroidal diamond-turned optics with starting rms roughness in the 3.3 to 3.7 nm range have been smoothed to the 0.4 to 0.6 nm range. EUV reflectometry characterization of these optics has demonstrated reflectivities of approximately 63%.
Date: January 1, 2005
Creator: Salmassi, Farhad; Naulleau, Patrick P. & Gullikson, Eric M.
Partner: UNT Libraries Government Documents Department

Biomimetic bonelike composites and novel bioactive glasscoatings

Description: Metallic orthopaedic implants have been successfully used for decades but they have serious shortcomings related to their osseointegration and the fact that their mechanical properties do not match those of bone. This paper reviews recent advances in the fabrication of novel coatings to improve implant osseointegration and in the development of a new generation of hybrid organic-inorganic implant materials specifically designed for orthopaedic applications.
Date: June 1, 2005
Creator: Tomsia, A.P.; Saiz, E.; Song, J. & Bertozzi, C.R.
Partner: UNT Libraries Government Documents Department

Comparison of National Bureau of Standards ceramic coatings L-7C and A-417 on turbine blades in a turbojet engine

Description: Report presenting an investigation to determine which of two ceramic coatings, L-7C and A-417, developed by the National Bureau of Standards is more suitable as a protective coating for turbine blades in a turbojet engine. Four cast Vitallium turbine blades, two coated with each of the ceramics, were installed in a turbine wheel of a turbojet engine and subjected to accelerated cyclic life tests.
Date: December 22, 1948
Creator: Morse, C. Robert
Partner: UNT Libraries Government Documents Department

Thermophysical, Interfacial and Decomposition Analyses of Polyhydroxyalkanoates introduced against Organic and Inorganic Surfaces

Description: The development of a "cradle-to-cradle" mindset with both material performance during utilization and end of life disposal is a critical need for both ecological and economic considerations. The main limitation to the use of the biopolymers is their mechanical properties. Reinforcements are therefore a good alternative but disposal concerns then arise. Thus the objective of this dissertation is to investigate a biopolymer nanocomposite where the filler is a synthetically prepared layer double hydroxide (inorganic interface); and a biopolymer paper (organic interface) based coating or laminate. The underlying issues driving performance are the packing density of the biopolymer and the interaction with the reinforcement. Since the polyhydroxyalkanoates or PHAs (the biopolymers used for the manufacture of the nanocomposites and coatings) are semicrystalline materials, the glass transition was investigated using dynamic mechanical analysis (DMA) and dielectric spectroscopy (DES), whereas the melt crystallization, cold crystallization and melting points were investigated using differential scanning calorimetry (DSC). Fourier transform infrared (FTIR) spectroscopy was used to estimate crystallinity in the coated material given the low thermal mass of the PHA in the PHA coating. The significant enhancement of the crystallization rate in the PHA nanocomposite was probed using DSC and polarized optical microscopy (POM) and analyzed using Avrami and Lauritzen-Hoffman models. Both composites showed a significant improvement in the mechanical performance obtained by DMA, tensile and impact testing. The degradation and decomposition of the two composites were investigated in low microbial activity soil for the cellulose paper (to slow down the degradation rate that occurs in compost) and in compost. An in-house system according to the American Society for Testing and Materials ASTM D-98 (2003) was engineered. Soil decomposition showed that PHA coating into and onto the cellulose paper can be considered to be a useful method for the assessment of the degradability of the biopolymer. ...
Date: December 2009
Creator: Dagnon, Koffi Leonard
Partner: UNT Libraries

Hypotheses for Scratch Behavior of Polymer Systems that Recover

Description: Scratch recovery is a desirable property of many polymer systems. The reason why some materials have demonstrated excellent scratch recovery while others do not has been a mystery. Explaining the scratch resistance based upon the hardness of a material or its crosslink density is incorrect. In this thesis, novel polymers were tested in an attempt to discover materials that show excellent scratch recovery - one of the most important parameters in determining the wear of a material. Several hypotheses were developed in an attempt to give an accurate picture of how the chemical structure of a polymer affects its scratch recovery. The results show that high scratch recovery is a complex phenomenon not solely dependent upon the presence of electronegative atoms such as fluorine.
Date: May 2002
Creator: Bujard, Bernard
Partner: UNT Libraries

Preliminary report on development of coating for alloy case

Description: Coatings examined were selected industrial finishes reported to have good resistance to corrosion and included epoxy resins reinforced with fiberglass. For screening purposes,this preliminary work was done on commercial sheet Mg to which had been applied a dichromate finish. The coatings were tested for impact resistance, corrosion resistance, abrasion resistance, and thermal shock resistance. Conclusions for further work are outlined.
Date: July 27, 1956
Creator: Archibald, P.B.
Partner: UNT Libraries Government Documents Department

Ultrahard Multilayer Coatings

Description: We have developed a new multilayer a-tC material that is thick stress-free, adherent, low friction, and with hardness and stiffness near that of diamond. The new a-tC material is deposited by J pulsed-laser deposition (PLD) at room temperature, and fully stress-relieved by a short thermal anneal at 600°C. A thick multilayer is built up by repeated deposition and annealing steps. We measured 88 GPa hardness, 1100 GPa Young's modulus, and 0.1 friction coefficient (under high load). Significantly, these results are all well within the range reported for crystalline diamond. In fact, this material, if considered separate from crystalline diamond, is the 2nd hardest material known to man. Stress-free a-tC also has important advantages over thin film diamond; namely, it is smooth, processed at lower temperature, and can be grown on a much broader range of substrates. This breakthrough will enable a host of applications that we are actively pursuing in MEMs, sensors, LIGA, etc.
Date: May 1, 1999
Creator: Chrzan, D.C.; Dugger, M.; Follstaedt, D.M.; Friedman, Lawrence H.; Friedmann, T.A.; Knapp, J.A. et al.
Partner: UNT Libraries Government Documents Department