Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D1/00—Casings; Linings; Walls; Roofs
  • F27D1/16—Making or repairing linings ; Increasing the durability of linings; Breaking away linings
  • F27D1/1678—Increasing the durability of linings; Means for protecting
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/28—Manufacture of steel in the converter
  • C21C5/42—Constructional features of converters
  • C21C5/46—Details or accessories
  • C21C5/4606—Lances or injectors
  • C21C5/4613—Refractory coated lances; Immersion lances
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/32—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer
  • C23C28/321—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one pure metallic layer with at least one metal alloy layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
  • C23C28/341—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one carbide layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
  • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/34—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates
  • C23C28/345—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer
  • C23C28/3455—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including at least one inorganic non-metallic material layer, e.g. metal carbide, nitride, boride, silicide layer and their mixtures, enamels, phosphates and sulphates with at least one oxide layer with a refractory ceramic layer, e.g. refractory metal oxide, ZrO2, rare earth oxides or a thermal barrier system comprising at least one refractory oxide layer
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
  • C23C28/30—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer
  • C23C28/36—Coatings combining at least one metallic layer and at least one inorganic non-metallic layer including layers graded in composition or physical properties
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
  • F27D3/00—Charging; Discharging; Manipulation of charge
  • F27D3/16—Introducing a fluid jet or current into the charge
  • F27D2003/168—Introducing a fluid jet or current into the charge through a lance
  • F27D2003/169—Construction of the lance, e.g. lances for injecting particles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12576—Boride, carbide or nitride component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
  • Y10T428/12611—Oxide-containing component
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12903—Cu-base component
  • Y10T428/1291—Next to Co-, Cu-, or Ni-base component

Definitions

• This invention relates to coatings for high temperature-corrosive applications.
• it relates to coatings useful for extending the service life under severe conditions, such as those associated with metallurgical vessels' lances, nozzles and tuyeres .
• Tuyeres often mounted on a bustle pipe inject air, oxygen and fuel into blast furnaces and smelters, such as Pierce-Smith converters. Similar to tuyeres, gas injection nozzles inject oxygen and fuel into electric arc furnaces' bath of molten steel. In addition, lance nozzles inject oxygen and fuel into basic oxygen furnaces used to manufacture steel . These lances, nozzles and tuyeres are usually water-cooled and made of high conductivity copper or copper-base alloys that have minimal resistance to molten slag or metal attack. In addition to these, metallurgical vessels' lances and nozzles typically experience both hot particle erosion and molten slag or metal attack. An additional problem is the presence of corrosive gases.
• corrosive gases include acids and non- acidic reactive metal vapors.
• the corrosive gases such as chlorine and sulfur dioxide often originate from fuels or the oxidation of metal sulfides in the feed stock or melt.
• reactive vapors such as, cadmium, lead, zinc, etc. typically originate from their inclusion in scrap steel feed to blast and electric arc furnaces.
• SOS copper sulfide
• Nakahira in US Pat. No. 3,977,660, discloses a blast furnace tuyere coating.
• This coating consists of a cermet deposited on either a nickel -base or cobalt- base self-fluxing alloy and an alumina or zironia ceramic layer covering the cermet.
• the major disadvantage of this coating is that the self-fluxing powder requires a two-step process to obtain an adequate bond to the tuyere. The process first spray coats the self-fluxing powder to the tuyere. Then it heats the powder (and tuyere) to bond the self-fluxing alloy to the tuyere. This heating process often imparts significant distortion upon the tuyere. atanbe et al .
• a detonation gun method and apparatus are described in US Pat. No. 2,714,563 and a Super D-GunTM method and apparatus are described in US Pat. No. 4,902,539.
• a detonation gun substantially comprises a normally cylindrical, water- cooled barrel with an inside diameter of about 25.4 mm, about 1 to 2 m in length, fitted near one end with supply valves. The gun is supplied with a gaseous mixture of at least one oxidizing gas (e.g., oxygen) and at least one fuel gas (e.g.
• acetylene as well as a powdered coating material, normally less than 100 micrometers in diameter.
• Nitrogen may be added to the gas mixture to reduce the temperature of the detonation.
• the gas mixture is ignited, usually with a spark, to produce a detonation wave. As the wave travels down the barrel, it heats the powder particles and accelerates the powder particles to a velocity greater than 750 m/s for a detonation gun and 1000 m/s for a Super D-Gun device.
• the coated device contains a coating for use with corrosive environments at high temperatures.
• the device has a bond coat consisting essentially of, by weight percent, 0 to 5 carbon, 20 to 40 chromium, 0 to 5 nickel, 0 to 5 iron, 2 to 25 total molybdenum plus tungsten, 0 to 3 silicon 0 to 3 boron and balance cobalt and essential impurities to provide sulfidation resistance at high temperatures.
• a zirconia-base ceramic coating covers the bond coat for heat resistance.
• a boride or carbide coating covers the zirconia for additional resistance to erosion.
• the method forms a coated device first coating the device with a cobalt-base bond coat. Then a thermal spray device melts at least a zirconia-base ceramic powder' s outer layer to form a partially molten zirconia powder. After melting the powder, the thermal spray device accelerates the partially molten zirconia- base ceramic powder to a velocity of a least 750 m/s to coat the bond coat with a series of interlocking zirconia-base ceramic agglomerations . The layer of zirconia-base ceramic agglomerations increases the coated device's heat resistance.
• the coating consists of a zirconia-base ceramic layer over an undercoat or bond layer of cobalt-base- sulfidation-resistant alloy.
• a third layer of boride or carbide coating may be applied over the ceramic for additional erosion resistance.
• the device coated is an injection device for a metallurgical vessel such as a lance, nozzle or tuyere. This coating is useful for devices constructed of various metals such as cobalt-base alloys, copper, copper-base alloys, nickel-base alloys and stainless steels. Most advantageously, this coating is applied to copper or copper-base alloys.
• the undercoat is a cobalt-base alloy resistant to sulfidation at high temperatures.
• the cobalt-base alloys of the invention advantageously contain, by weight percent, about 20 to 40 percent chromium- -unless specifically expressed otherwise, all compositions provided in this specification are expressed in weight percent.
• the chromium provides oxidation resistance and some additional resistance to oxidation for the cobalt matrix.
• a total addition of about 3 to 20 molybdenum and tungsten greatly enhances the alloy' s sul idation resistance. This is particularly important for protecting copper and copper-base alloy devices used in connection with molten metal. At the high temperatures generated with smelting and processing molten iron and steel, copper injection devices quickly react with sulfur dioxide to form detrimental CuS . The change in density associated with the sulfidation often causes ceramic coatings to spall off. In addition, ceramic coatings generally tend to have porosity and cracks that permeate the ceramic coating. These defects in the coating provide sites subject to severe crevice corrosion.
• the coating contain at least 2 percent tungsten or molybdenum to increase the alloy' s sulfidation resistance.
• the alloy contains at least 3 percent tungsten.
• the alloy contains up to 5 percent carbon to strengthen the alloy. Carbon levels above five percent tend to decrease the corrosion resistance of the alloy.
• the alloy may contain up to three weight percent silicon or boron to lower the melting temperature of the powder. This facilitates spraying the powder as molten or partially molten powder. This spraying of molten or partially molten powder improves the interlocking of the splats formed with the thermal spray device.
• the cobalt-base bond layer relies upon a mechanical bonds to secure it to the substrate. This avoids the distortion often associated with the use of self-fluxing alloys.
• the bond layer advantageously contains about the following composition, by weight percent, expressed in
• Table 2 lists some specific examples of sulfur dioxide resistant cobalt-base alloys.
• a ceramic zirconia-base layer covers the sulfidation resistant underlayer.
• the zirconia-base layer is selected from the group consisting of zirconia, partially stabilized zirconia and fully stabilized zirconia.
• this layer is a partially stabilized zirconia, such as calcia, ceria or other rare earth oxides, magnesia and yttria-stabilized zirconia.
• the most preferred stabilizer is yttria.
• the partially stabilized zirconia Zr0 2 -8Y 2 0 3 provides excellent resistant to heat and slag/metal adhesion.
• the zirconia-base ceramic layer advantageously has a density of at least about eighty percent to limit the corrosive effects of hot acidic gases upon the under layer. Most advantageously, this density is at least about ninety percent.
• the optional top layer that covers the ceramic is a heat and hot erosion resistant carbide or boride coating.
• the coating material may be any heat resistant chromium boride or carbide such as, CrB, Cr 3 C 2 , Cr 7 C 3 or Cr 3 C 6 .
• the coating may be a pure carbide/boride or in a heat resistant alloy matrix of cobalt or nickel-base superalloy.
• each layer can be varied depending on the application and service environment.
• each layer has a thickness between about 50 to 1,000 micrometers (0.002" to 0.040").
• Plasma, HVOF, and detonation gun and Super D-GunTM techniques are effective for the under coat and the optional top layer. But, since HVOF provides insufficient melting of zirconia-based powders, the zirconia-base ceramic coatings can only be applied with plasma, detonation gun, or Super D-GunTM processes.
• first and second layers can be a continuously graded coating starting with 100 percent alloy and ending with at least 99 percent ceramic.
• the ideal technique for this graded coating are detonation gun or Super D-GunTM devices .
• the zirconia-base coating is preferably deposited on exposed surfaces of the inj'ection device such as tuyeres, lances or nozzles by means of a thermal spray process using a detonation gun or a Super D-GunTM device.
• the coating material particles are therefore heated to a high temperature and accelerated to a high velocity (Super D-Gun is a trademark of Praxair Surface Technologies, Inc.).
• Super D-Gun is a trademark of Praxair Surface Technologies, Inc.
• the particle velocity is greater than about 750 m/sec for detonation gun deposition and greater than about 1000 m/sec for Super D-GunTM deposition. The increased particle velocity improves bonding or adherence of the coating to the injection device.
• a molten or semi- molten state particles against the exposed surface forms an agglomeration of thin lamellar particles. These particles are overlapping, intertwined, and densely packed. Each detonation generates a circular agglomeration or splat of particles, and the continuous coating is built-up on the exposed surface to be coated by traversing the gun relative to the exposed surface in a predetermined pattern of overlapping circular agglomerations of particles.
• other thermal spray or related processes such as high velocity oxy- fuel, high velocity air fuel, and cold spray may be viable if they are capable of generating sufficient particle velocity and particle temperature.
• each circular agglomeration of particles deposited on at least one exposed surface of the injection device forms the coating portions of less than about 25 micrometers in thickness and about 15 mm to 35 mm in diameter.
• the method forms a coating on a portion or all of exposed surfaces of the lance, nozzle or tuyere.
• it relates to depositing a coating of predetermined thickness on the exposed surface of a tuyere or other gas injection device.
• the process uses a thermal spray device to coat the entire exposed surface of the injection device.
• the powder particles of coating material are advantageously projected in a molten or semi-molten form against the surface of the coated device on which they flow into thin lamellar particles and are quenched very rapidly to a solid form at relatively low temperatures to form an agglomeration with a microstructure of interlocking, tightly bonded, lamellar particles.
• Each detonation deposits a coating portion or agglomeration that is typically less than about 20 micrometers thick and about 25 micrometers in diameter.
• the total coating thickness comprises multiple layers generated by traversing the gun relative to the surface to be coated in a predetermined manner such that the total coating thickness is generated by precisely placed agglomerations of coating material in an overlapping pattern.
• the barrel of the gun is swept clean with a pulse of nitrogen and the process repeated.
• the detonation process is repeated several times a second so that the overall coating process is completed in a relatively short time.
• Each step in the process is automated and precisely controlled.
• a major advantage of most of the thermal spray processes is the ability to deposit coatings, even those of very high melting points, without significantly heating the substrate or the part being coated. Occasionally, auxiliary cooling such a jets of air or carbon dioxide are directed on the part being coated.
• the part temperature can be held below 150 °C without difficulty, thus no distortion or changes in the properties of the part typically associated with high temperature processes occur.
• the step of depositing the coating on the exposed surface of the device may be preceded by a preliminary step of preparing the surface by, for example, grit blasting, and may be followed by a step of finishing the coated surface.
• Ceramic Coating Yttria stabilized zirconia (Zr0 2 - 8Y 2 0 3 ) , 0.002" to 0.006" (50 to 150 micrometers) of Super D-GunTM.
• the zirconia coating produced with a
• Super D-GunTM device has greater erosion resistance than an equivalent coating produced with a plasma technique .
• Optional Carbide Layer Chromium carbide (Cr 3 C 2 ) or 80% Cr 3 C 2 with 20% alloy 718 (50.0-55.0 Ni + Co, 17.0 to 21.0 Cr, 4.75-5.50 Nb, 2.80-3.30 Mo, 0.65-1.15 Ti, 0.20-0.80 Al and 1.0 max. Co). Apply 0.001" to 0.004" (25 to 100 micrometers) with a Super D-GunTM device.
• the optional carbide coating provides additional resistance to the detrimental attack of the reactive metal vapors.
• the surfaces of the tuyeres to be coated were first cleaned and then grit blasted.
• the Super D-GunTM used was a conventional gun using oxygen, acetylene and a fraction of propylene as the fuel gas, and nitrogen as a diluent.
• the process parameters were chosen to accelerate the particles to a velocity higher than about 1000 m/s and to heat them to a temperature such that most, but not all of the material was molten. Cooling jets of gas were used during the coating process and the temperature of the tuyere was maintained at less than 150 °C.
• the Co-Cr- (Mo, ) /zironia-base ceramic coating provides the following benefits: 1) excellent protection to corrosive acids and metal vapors; 2) heat resistance; 3) protection against metal and slag build up; 4) low erosion rates when exposed to splashing metal; and 5) resistance to thermal cyclic fatigue.
• the coating protects copper and copper-base alloys from the most severe service conditions.
• the optional boride or carbide barrier can provide additional resistance to corrosive effects of hot gases and reactive metal vapors.
• using a thermal spray device to deposit molten or partially molten agglomerations of zirconia-base ceramics increases the density and bond strength of the zirconia to further improve the coating's performance.
• This coating is particularly useful for lances, nozzles and tuyeres that are subject to the hot gases and splashing metal .
• changes can be made to the relative fabrication methods as described herein without departing from the scope of the present invention.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Inorganic Chemistry (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Ceramic Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Coating By Spraying Or Casting (AREA)

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• 2001
  • 2001-03-19 US US09/810,451 patent/US6503442B1/en not_active Expired - Lifetime
• 2002
  • 2002-02-25 WO PCT/US2002/005478 patent/WO2002075004A1/en not_active Ceased
  • 2002-02-25 DE DE60216751T patent/DE60216751T2/de not_active Expired - Lifetime
  • 2002-02-25 EP EP02717494A patent/EP1390549B1/en not_active Expired - Lifetime
  • 2002-02-25 JP JP2002574392A patent/JP2004532930A/ja not_active Ceased

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