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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

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

A correlation between EIS and salt spray proof tests for the corrosion resistance of conversion coated aluminum alloys

Description: In this study, 33 different conversion coatings were applied to 5 different Al alloy substrates. Salt spray exposure testing and EIS (electrochemical impedance spectroscopy) were conducted for comparison. A relation was developed.
Date: September 1, 1996
Creator: Buchheit, R.G.; Martinez, M.A.; Cunningham, M.; Jensen, H. & Kendig, M.W.
Partner: UNT Libraries Government Documents Department

The response of hydrotalcite coated aluminum to sealing with transition metal salt solutions

Description: Objective was to determine if the protective coating could be enhanced by filling intercrystalline spaces or by reinforcing the coating at intermetallic particles by exposure to aqueous transition metal salt solutions. Two oxy-anion analogs to chromate were used: permanganate and molybdate. Ce(III) (as Ce(NO{sub 3}){sub 3}) was also studied. (Al alloys 2024-T3 and 6061-T6 were used as substrates.) Results are summarized. 4 figs, 1 tab, 3 refs.
Date: 1994
Creator: Buchheit, R. G. & Martinez, M. A.
Partner: UNT Libraries Government Documents Department

Abstracted model for ceramic coating

Description: Engineers are exploring several mechanisms to delay corrosive attack of the CAM (corrosion allowance material) by dripping water, including drip shields and ceramic coatings. Ceramic coatings deposited with high-velocity oxyfuels (HVOF� s) have exhibited a porosity of only 2% at a thickness of 0.15 cm. The primary goal of this document is to provide a detailed description of an abstracted process-level model for Total System Performance Assessment (TSPA) that has been developed to account for the inhibition of corrosion by protective ceramic coatings. A second goal was to address as many of the issues raised during a recent peer review as possible (direct reaction of liquid water with carbon steel, stress corrosion cracking of the ceramic coating, bending stresses in coatings of finite thickness, limitations of simple correction factors, etc.). During the periods of dry oxidation (T 2 100°C) and humid-air corrosion (T I 100°C & RH < SO%), it is assumed that the growth rate of oxide on the surface is diminished in proportion to the surface covered by solid ceramic. The mass transfer impedance imposed by a ceramic coating with gas-filled pores is assumed to be negligible. During the period of aqueous phase corrosion (T I 100°C & RH > 80%), it is assumed that the overall mass transfer resistance governing the corrosion rate is due to the combined resistance of ceramic coating & interfacial corrosion products. Two porosity models (simple cylinder & cylinder-sphere chain) are considered in estimation of the mass transfer resistance of the ceramic coating. It is evident that substantial impedance to 02 transport is encountered if pores are filled with liquid water. It may be possible to use a sealant to eliminate porosity. Spallation (rupture) of the ceramic coating is assumed to occur if the stress introduced by the expanding corrosion products at the ...
Date: November 14, 1998
Creator: Farmer, J C & Stockman, C
Partner: UNT Libraries Government Documents Department

Application of thick film and bulk coating technology to the Subterrene program

Description: From conference on structure-property relationships in thick film and bulk coatings; San Francisco, California, USA (28 Jan The Subterrene is a rock- melting earth-penetration system representing a significant advancement in excavation technology. Temperatures of 1700-2000 deg K are involved, and heated refractorymetal or alloy probes are used. Corrosion problems are severe on the exterior surfaces of the refractory metals used; bulk coatings having the required properties would be extremely desirable provided they could be deposited upon a substrate as a tenacious coating. Within the Subterrene, pyrographite radiant heaters are operating at temperatures to 2450 deg K. Graphite receptors added to improve the radiant heat transfer react with the Mo and W penetrator bodies to form carbides. A 30 mu m-thick CVD film of TaC may be applied to inhibit this reaction. The techniques of applying these fllms, their nature, and the results of their application, are discussed. The environment of an operating penetrator is described, and the requirements and properties of exterior coatings are outlined. (auth)
Date: January 1, 1974
Creator: Stark, W.A. Jr.; Wallace, T.C.; Witteman, W.; Krupka, M.C.; David, W.R. & Radosevich, C.
Partner: UNT Libraries Government Documents Department

NOVEL REFRACTORY MATERIALS FOR HIGH ALKALI, HIGH TEMPERATURE ENVIRONMENTS

Description: Refractory materials can be limited in their application by many factors including chemical reactions between the service environment and the refractory material, mechanical degradation of the refractory material by the service environment, temperature limitations on the use of a particular refractory material, and the inability to install or repair the refractory material in a cost effective manner or while the vessel was in service. The objective of this project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al 2O3 spinel or other similar magnesia/alumina containing unshaped refractory composition (castables, gunnables, shotcretes, etc) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, high-alkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries.
Date: September 1, 2011
Creator: Hemrick, James Gordon
Partner: UNT Libraries Government Documents Department

COMBUSTION TURBINE (CT) HOT SECTION COATING LIFE MANAGEMENT

Description: The integrity of coatings used in hot section components of combustion turbines is crucial to the reliability of the buckets. This project was initiated in recognition of the need for predicting the life of coatings analytically, and non-destructively; correspondingly, four principal tasks were established. Task 1, with the objective of analytically developing stress, strain and temperature distributions in the bucket and thereby predicting thermal fatigue (TMF) damage for various operating conditions; Task 2 with the objective of developing eddy current techniques to measure both TMF damage and general degradation of coatings and, Task 3 with the objective of developing mechanism based algorithms. Task 4 is aimed at verifying analytical predictions from Task 1 and the NDE predictions from Task 3 against field observations.
Date: March 31, 2006
Creator: Gandy, D.; Viswanathan, R.; Cheruvu, S. & Krzywosz, K.
Partner: UNT Libraries Government Documents Department

Electrically Conductive, Corrosion-Resistant Coatings Through Defect Chemistry for Metallic Interconnects

Description: The principal objective of this work was to develop oxidation protective coatings for metallic interconnect based on a defect chemistry approach. It was reasoned that the effectiveness of a coating is dictated by oxygen permeation kinetics; the slower the permeation kinetics, the better the protection. All protective coating materials investigated to date are either perovskites or spinels containing metals exhibiting multiple valence states (Co, Fe, Mn, Cr, etc.). As a result, all of these oxides exhibit a reasonable level of electronic conductivity; typically at least about {approx}0.05 S/cm at 800 C. For a 5 micron coating, this equates to a maximum {approx}0.025 {Omega}cm{sup 2} area specific resistance due to the coating. This suggests that the coating should be based on oxygen ion conductivity (the lower the better) and not on electronic conductivity. Measurements of ionic conductivity of prospective coating materials were conducted using Hebb-Wagner method. It was demonstrated that special precautions need to be taken to measure oxygen ion conductivity in these materials with very low oxygen vacancy concentration. A model for oxidation under a protective coating is presented. Defect chemistry based approach was developed such that by suitably doping, oxygen vacancy concentration was suppressed, thus suppressing oxygen ion transport and increasing effectiveness of the coating. For the cathode side, the best coating material identified was LaMnO{sub 3} with Ti dopant on the Mn site (LTM). It was observed that LTM is more than 20 times as effective as Mn-containing spinels. On the anode side, LaCrO3 doped with Nb on the Cr site (LNC) was the material identified. Extensive oxidation kinetics studies were conducted on metallic alloy foils with coating {approx}1 micron in thickness. From these studies, it was projected that a 5 micron coating would be sufficient to ensure 40,000 h life.
Date: December 31, 2006
Creator: Virkar, Anil V.
Partner: UNT Libraries Government Documents Department

Reactive multilayer synthesis of hard ceramic foils and films

Description: Disclosed is method for synthesizing hard ceramic materials such as carbides, borides and aluminides, particularly in the form of coatings provided on another material so as to improve the wear and abrasion performance of machine tools, for example. Method involves the sputter deposition of alternating layers of reactive metals with layers of carbon, boron, or aluminum and the subsequent reaction of the multilayered structure to produce a dense crystalline ceramic. The material can be coated on a substrate or formed as a foil which can be coiled as a tape for later use.
Date: December 31, 1993
Creator: Makowiecki, D.M. & Holt, J.B.
Partner: UNT Libraries Government Documents Department

Transmission electron microscopy of undermined passive films on stainless steel

Description: A study has been made of the passive film remaining over pits on stainless steel using a high resolution transmission electron microscope. Type 305 stainless steel was passivated in a borate buffer solution and pitted in ferric chloride. Passive films formed at 0.2 V relative to a saturated calomel electrode were found to be amorphous. Films formed at higher potentials showed only broad diffraction rings. The passive film was found to cover a remnant lacy structure formed over pits passivated at 0.8 V. The metallic strands of the lace were roughly hemitubular in shape with the curved surface facing the center of the pit.
Date: June 1, 1999
Creator: Isaacs, H.S.; Zhu, Y.; Sabatini, R.L. & Ryan, M.P.
Partner: UNT Libraries Government Documents Department

Advanced turbine systems - research and development of thermal barrier coatings technology: 2nd bimonthly report, February 1996

Description: Objective of the ATS program is the development of ultra-highly efficient, environmentally superior, and cost-competitive gas turbine systems, with long, less cyclic operating profiles than aircraft gas turbine engines. Durability and performance demands of ATS can be achieved by means of thermal barrier coatings. Phase I (program plan) is complete. Phase II is in progress.
Date: February 1, 1996
Partner: UNT Libraries Government Documents Department

Warehouse Plan for the Multi Canister Overpack (MC0) and Baskets

Description: The Multi-Canister Overpacks (MCO) will contain spent nuclear fuel (SNF) removed from the K East and West Basins. The SNF will be placed in fuel storage baskets that will be stacked inside the MCOs. Approximately 400 MCOs and 21 70 baskets will be fabricated for this purpose. These MCOs, loaded with SNF, will be placed in interim storage in the Canister Storage Building (CSB) located in the 200 Area of the Hanford Site. The MCOs consist of different components/sub-assemblies that will be manufactured by one or more vendors. All component/sub-assemblies will be shipped to the Hanford Site Central Stores Warehouse, 2355 Stevens Drive, Building 1163 in the 1100 Area, for inspection and storage until these components are required at the CSB and K Basins. The MCO fuel storage baskets will be manufactured in the MCO basket fabrication shop located in Building 328 of the Hanford Site 300 Area. The MCO baskets will be inspected at the fabrication shop before shipment to the Central Stores Warehouse for storage. The MCO components and baskets will be stored as received from the manufacturer with specified protective coatings, wrappings, and packaging intact to maintain mechanical integrity of the components and to prevent corrosion. The components and baskets will be shipped as needed from the warehouse to the CSB and K Basins. This warehouse plan includes the requirements for receipt of MCO components and baskets from the manufacturers and storage at the Hanford Site Central Stores Warehouse. Transportation of the MCO components and baskets from the warehouse, unwrapping, and assembly of the MCOs are the responsibility of SNF Operations and are not included in this plan.
Date: March 27, 2000
Creator: MARTIN, M.K.
Partner: UNT Libraries Government Documents Department

A performance evaluation of coating systems for long term aqueous immersion service

Description: The static immersion of coated steel panels in various media representative of chemical and waste processes around the Oak Ridge Y-12 Plant was terminated after 16 months exposure for evaluation of coating performance and comparison with observations collected following 1, 6, and 11 months exposure. In each environment, a wide range of coating performance was observed, including some coatings unsuitable for use in the test environment (despite the high recommendation of the vendor). Further, coating performance as a function of time suggests a test duration of at least several months is required to fully assess candidate coating performance for specific applications. The performance of many coatings, particularly in the most alkaline environment, was adversely affected by the imposition of supplemental cathodic protection on the coated test panels.
Date: November 8, 1994
Creator: Pawel, S.J.
Partner: UNT Libraries Government Documents Department

High-temperature oxidation/sulfidation resistance of iron-aluminide coatings

Description: Iron aluminides containing > 20-25 at. % Al have oxidation and sulfidation resistance at temperatures well above those at which these alloys have adequate mechanical strength. Accordingly, these alloys may find application as coatings or claddings on more conventional higher-strength materials which are generally less corrosion-resistant at high temperatures. To this end, iron-aluminide coatings were prepared by gas tungsten arc and gas metal arc weld-overlay techniques. Specimens were cut from weld deposits and exposed to a highly aggressive oxidizing-sulfidizing (H2S-H2-H2O-Ar) environment at 800 C. All the weld overlayers showed good corrosion behavior under isothermal conditions, including a gas metal arc-produced deposit with only 21 at. % Al. Rapid degradation in corrosion resistance was observed under thermal cycling conditions when the initally grown scales spalled and the rate of reaction was then not controlled by formation of slowly growing Al oxide. Higher starting Al concentrations (> {approximately} 25 at. %) are needed to assure overall oxidation-sulfidation resistance of the weld overlays, but hydrogen cracking susceptibility must be minimized in order to physically separate the corrosive species from the reactive substrate material.
Date: April 1, 1996
Creator: Tortorelli, P.F.; Wright, I.G.; Goodwin, G.M. & Howell, M.
Partner: UNT Libraries Government Documents Department

Low-temperature hermetic sealing of optical fiber components

Description: A method for manufacturing low-temperature hermetically sealed optical fiber components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber.
Date: December 31, 1995
Creator: Kramer, D.P.
Partner: UNT Libraries Government Documents Department

Advanced turbine systems - research and development of thermal barrier coatings technology: 3rd bimonthly report, April 1996

Description: Objective of the ATS program is the development of ultra-highly efficient, environmentally superior, and cost-competitive gas turbine systems, using thermal barrier coatings. These coatings should be stable in the thermal and corrosive environments of the industrial engine for up to 2500 hours. Phase II (development) is current.
Date: April 1, 1996
Partner: UNT Libraries Government Documents Department

Coating concrete secondary containment structures exposed to agrichemicals

Description: Concrete has traditionally been the material of choice for building secondary containment structures because it is relatively inexpensive and has structural properties which make it ideal for supporting the loads of vehicles and large tanks. However, concrete`s chemical properties make it susceptible to corrosion by some common fertilizers. Though fairly impervious to water movement, concrete is easily penetrated by vapors and solvents. It is also prone to cracking. For these reasons, the Environmental Protection Agency (EPA) believes that concrete alone may not provide an effective barrier to pesticide movement and has proposed that concrete in pesticide secondary containment structures be sealed or coated to reduce its permeability. Some state secondary containment regulations require that concrete exposed to fertilizers and pesticides be sealed or protected with a coating. Lacking guidelines, some retailers have used penetrating sealants to satisfy the law, even though these products provide little protection from chemical attack nor do they prevent pesticide egress. Other retailers who have applied thick film coatings which were properly selected have had disastrous results because the application was poorly done. Consequently, much skepticism exists regarding the performance and benefit of protective coatings.
Date: June 1, 1995
Creator: Broder, M.F. & Nguyen, D.T.
Partner: UNT Libraries Government Documents Department

Influence of environmental parameters on the frictional behavior of DLC coatings

Description: In a previous studies it was shown that diamond like carbon (DLC) films possess low friction coefficient (f) and excellent wear resistance. The reduction in f was found to be consistent with a ``wear induced graphitization`` mechanism of the DLC structure. A recent study showed that operational parameters (sliding velocity and loading level) influence the tribological behavior of DLC film through control of the kinetics of the graphitization process. The objective of the present study was to investigate the influence of environmental parameters (humidity and temperature) on the tribological behavior of DLC film and provide further support to the wear induced graphitization mechanism. Ion beam deposition was utilized to deposit DLC on a SiC substrate. Pin-on-disc experiments were conducted by varying humidity (0%, 40% and 100%) and temperature ({minus}10 C and 25 C). As-deposited DLC and wear debris was characterized by transmission electron microscopy. It was found that lower humidity increases the graphitization rate more than likely due to the reduction in the effect by the water molecules. A decreased graphitization rate was observed at lower temperature and higher humidity and can be attributed to suppression of temperature rise at hot spots. The present findings are consistent with and further verify the wear induced graphitization mechanism.
Date: May 1, 1997
Creator: Liu, Y.; Erdemir, A. & Meletis, E.I.
Partner: UNT Libraries Government Documents Department

Energy-efficient process for hot-dip batch galvanizing

Description: Hot-dip galvanizing of steel sheets, pipes, and other fabrication items is a popular method of corrosion protection. Currently, steel articles are immersed in molten zinc at 860{degrees}F, thereby forming a {open_quotes}frozen{close_quotes} metal (interfacial zinc iron intermetallic layer) on the surface. Drawbacks to the current technology include the expense of heating parts at such a high temperature and the generation of by-products such as zinc alloys, zinc oxides, and smoke. Furthermore, new federal regulations have significantly reduced acceptable lead levels in coatings, because lead from galvanized, coated steel will dissolve in water. Such dissolved lead may accumulate in human bodies with deleterious results. Additionally, the use of a molten salt layer on top of zinc (top-flux) causes kettle smoke and ash evolution. Ferro Technologies, Inc. has proposed a lead-free batch technology that will significantly improve the galvanizing process. The new Thermo Prep{trademark} process protects steel surfaces with a thermally stable flux by preheating parts to 400{degrees}F to 450{degrees}F in a separate furnace, and then immersing them in molten, lead-free zinc for a short period of time. The use of a thermally stable pre-flux would eliminate the need for top-flux, thereby reducing associated wastes.
Date: April 1, 1998
Partner: UNT Libraries Government Documents Department

Investigation of machining damage and tool wear resulting from drilling powder metal aluminum alloy

Description: This report documents the cutting of aluminum powder metallurgy (PM) parts for the North Carolina Manufacturing Extension Partnership. The parts, an aluminum powder metal formulation, were supplied by Sinter Metals Inc., of Conover, North Carolina. The intended use of the alloy is for automotive components. Machining tests were conducted at Y-12 in the machine shop of the Skills Demonstration Center in Building 9737. Testing was done on June 2 and June 3, 1997. The powder metal alloy tested is very abrasive and tends to wear craters and produce erosion effects on the chip washed face of the drills used. It also resulted in huge amounts of flank wear and degraded performance on the part of most drills. Anti-wear coatings on drills seemed to have an effect. Drills with the coating showed less wear for the same amount of cutting. The usefulness of coolants and lubricants in reducing tool wear and chipping/breakout was not investigated.
Date: May 1, 1997
Creator: Fell, H.A.
Partner: UNT Libraries Government Documents Department