Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L57/00—Protection of pipes or objects of similar shape against external or internal damage or wear
  • F16L57/06—Protection of pipes or objects of similar shape against external or internal damage or wear against wear
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/24—Electrically-conducting paints
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4419—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications with polymers obtained otherwise than by polymerisation reactions only involving carbon-to-carbon unsaturated bonds
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/44—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications
  • C09D5/4476—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes for electrophoretic applications comprising polymerisation in situ
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
  • C10M169/041—Mixtures of base-materials and additives the additives being macromolecular compounds only
• • 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
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/82—After-treatment
  • C23C22/83—Chemical after-treatment
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D13/00—Electrophoretic coating characterised by the process
  • C25D13/04—Electrophoretic coating characterised by the process with organic material
  • C25D13/06—Electrophoretic coating characterised by the process with organic material with polymers
  • C25D13/08—Electrophoretic coating characterised by the process with organic material with polymers by polymerisation in situ of monomeric materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
  • F16L15/08—Screw-threaded joints; Forms of screw-threads for such joints with supplementary elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
  • F16L58/02—Protection of pipes or pipe fittings against corrosion or incrustation by means of internal or external coatings
  • F16L58/04—Coatings characterised by the materials used
  • F16L58/10—Coatings characterised by the materials used by rubber or plastics
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L58/00—Protection of pipes or pipe fittings against corrosion or incrustation
  • F16L58/18—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings
  • F16L58/182—Protection of pipes or pipe fittings against corrosion or incrustation specially adapted for pipe fittings for screw-threaded joints
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
  • C08L79/02—Polyamines
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
  • C10M2201/04—Elements
  • C10M2201/041—Carbon; Graphite; Carbon black
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
  • C10M2201/04—Elements
  • C10M2201/041—Carbon; Graphite; Carbon black
  • C10M2201/0413—Carbon; Graphite; Carbon black used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
  • C10M2201/06—Metal compounds
  • C10M2201/065—Sulfides; Selenides; Tellurides
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2201/00—Inorganic compounds or elements as ingredients in lubricant compositions
  • C10M2201/06—Metal compounds
  • C10M2201/065—Sulfides; Selenides; Tellurides
  • C10M2201/0653—Sulfides; Selenides; Tellurides used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
  • C10M2215/22—Heterocyclic nitrogen compounds
  • C10M2215/223—Five-membered rings containing nitrogen and carbon only
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2217/00—Organic macromolecular compounds containing nitrogen as ingredients in lubricant compositions
  • C10M2217/04—Macromolecular compounds from nitrogen-containing monomers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
  • C10M2217/046—Polyamines, i.e. macromoleculars obtained by condensation of more than eleven amine monomers
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/12—Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2050/00—Form in which the lubricant is applied to the material being lubricated
  • C10N2050/015—Dispersions of solid lubricants
  • C10N2050/02—Dispersions of solid lubricants dissolved or suspended in a carrier which subsequently evaporates to leave a lubricant coating
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2050/00—Form in which the lubricant is applied to the material being lubricated
  • C10N2050/08—Solids
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2060/00—Chemical after-treatment of the constituents of the lubricating composition
  • C10N2060/10—Chemical after-treatment of the constituents of the lubricating composition by sulfur or a compound containing sulfur

Definitions

• This invention relates to corrosion-protection and lubrication of metal surfaces.
• the invention relates to a method of protecting a metal surface, such as the surface of threaded joints in oil tubings or casings, by applying a dry film including a binding intrinsically conductive polymer to the surface.
• the invention also relates to a composition for protecting a metal surface from galling and corrosion.
• Intrinsically Conductive Polymers and Corrosion Protection are known in the art.
• One example of an intrinsically conductive polymer is polyaniline, which has been known to modify the electrochemical and corrosion behavior of stainless steels.
• DeBerry has determined that stainless steel electrodes coated with thin films of polyaniline remain passive for long periods of time in acid solutions, even though normally they would be active and highly susceptible to corrosion in such environments (J Electrochem. Soc: Electrochemical Science and Technology 132 (5) (1985) 1022-1026).
• Polyaniline can be an electrical conductor depending on its state of oxidation or doping.
• the corrosion protection mechanism involves both the conductive and the non- conductive states of polyaniline.
• Wessling et al. (Synth. Met. 85 (1997) 1313-1318) have proposed a corrosion protection mechanism including the following steps: 1) Polyaniline in its conductive state (i.e., emeraldine base) depolarizes ferrous metal by accepting electrons, forming non-conductive polyaniline (leucoemeraldine). 2) Atmospheric oxygen regenerates the polyaniline to its conductive state (emeraldine).
• Lu et al. have disclosed corrosion protection of mild steel by coatings containing polyaniline (Synth. Met. 71 (1995) 2163-2166), while Camalet et al. have disclosed the electrodeposition of protective polyaniline films on mild steel (J Electroanalytical Chem. A ⁇ 6 (1996) 179-182).
• Rajagopalan et al. have disclosed two-intrinsically conductive- polymer, polyamline-polypyrrole composite coatings formed on low carbon steel using an aqueous electrochemical process, which have anti-corrosive properties (Surface Engineering 18 (1) (2002) 53-63).
• Intrinsically conductive polymers have also been used as general binding agents and combined in composites with corrosion protection agents, such as 2,5-dimercapto- 1,3,4 thiadiazole or trithiocyanuric acid (U.S. Patent Publication 2002/0197468 Al, Sinko).
• inherently conductive or intrinsically conductive is sometimes used (for example, in U.S. Patent No. 5,567,355 to Wessling et al.) to describe conjugated materials (such as polyaniline) that do not require the addition of conductive materials (such as carbon or metal particles), but may or may not require doping (oxidation and/or protonation), in order to be conductive.
• conjugated materials such as polyaniline
• conductive materials such as carbon or metal particles
• doping oxidation and/or protonation
• polyaniline Unlike non-conductive polymers such as titanates, silicones, epoxies, polyurethanes, and the like, the conductive properties of polyaniline account for both the anticorrosion mechanism and the possibility of an industrial application by electrodeposition or electrophoresis in a single step at high speed, without the use of solvent, thus reducing slow drying steps.
• Polyaniline can also be sprayed or brush- painted on metal surfaces, like other polymers.
• Galling is a form of surface damage arising between sliding solids, distinguished by macroscopic, usually localized, roughening and creation of protrusions above the original surface. It often includes plastic flow or material transfer, or both. (ASTM definition.)
• a number of surface treatments are known for protection from galling of metal surfaces, such as the threaded connections of oil pipe joints.
• molybdenum disulfide, colloidal graphite, and other compounds that present similar lamellar structures in the solid phase are commonly used as lubricants of metal surfaces. Such solid lubricants have been included in dry films with ketonic resins (U.S. Patent No. 4,692,988 to Shulver), epoxy resins (Chinese Patent No.
• compositions usually include a curing agent and may contain toughening agents in the case of rubber binders.
• U.S. Patent No. 4,692,988 to Shulver proposes applying a dry lubricant such as molybdenum disulfide to a screw thread, and applying a liquid lubricant such as oil to the other screw thread, during the assembly of a connection. Therefore, the patent does not disclose a dry lubricating process. It also does not disclose the use of conductive polymer to lubricate or protect from corrosion.
• PCT Publication WO 02/18522 Al (Vallourec Mannesmann Oil & Gas France, and Condat S.A.), which relates to a threaded joint for oil well pipes, also teaches the use of oil in a lubricating substance applied to a threaded component, so it cannot be considered to disclose a dry lubricating process.
• PCT Publication WO 01/16516 Al discloses a rust-inhibiting coating including a layer of oil containing rust inhibitors. This coating is applied to a threaded joint, over a coating of dry lubricant, and must be removed in the oil field before assembling the connection, thus complicating operations.
• U.S. Patent No. 6,027,145 to Tsuru et al. which relates to a threaded joint having high galling resistance, discloses a resin coating layer in which at least one powder selected from the group consisting of molybdenum disulfide and tungsten disulfide is dispersed and mixed.
• the resins are epoxy, furan, or polyamide, which are very different from the conductive polymers of this invention.
• the resin layer is formed on, and has a thickness larger than, a phosphate chemical formation coating layer.
• the patent does not teach the use of an intrinsically conductive polymer layer as an anti-galling and anti- corrosive coating, alone or in combination with molybdenum disulfide.
• U.S. Patent Publication 2002/0166770 Al discloses a process for producing a multi-layer coating.
• a primer layer which is electrically conductive in the at least partially-cured state, is applied by electrodeposition from an electrodeposition coating agent (I) to an electrically conductive object.
• the primer layer is at least partially cured exclusively by the action of near infra-red radiation, and an additional coating layer is applied by electrodeposition from an electrodeposition coating agent (II).
• the additional coating layer as well as completely uncured or incompletely cured area parts of the primer layer, are then cured.
• the electrodeposition coating agent (I) contains one or more electrically conductive constituents, which confer a volume resistivity on the electrodeposition coating layer and may include, among other possibilities, graphite, molybdenum disulfide, or intrinsically conductive polymers such as polyaniline. This publication does not teach that the multi-layer coating has lubricant properties. [0021] U.S.
• Patent Publication 2002/0114940 discloses a coating system that includes a basecoat of a thermosetting asphalt extended, chemically cross-linked urethane/epoxy hybrid basecoat resting on a substrate, and a thermoplastic powder coating topcoat overlying at least the base coat.
• Corrosion inhibitors which include polyaniline
• fillers and lubricants which include molybdenum disulfide
• polyaniline is used as a corrosion protection additive, not as a binding intrinsically conductive polymer.
• Italian Patent Application RM 2002 A000512 (Tenaris Connections Ltd./AG) discloses a surface treatment including a first uniform layer of a dry corrosion inhibiting coating and a second uniform layer of a dry lubricant coating applied over the first layer. It also discloses a uniform layer of dry corrosion inhibiting coating that contains a dispersion of particles of solid lubricant. However, the application does not teach a homogeneous layer of an intrinsically conductive, anti-corrosive polymer, which itself prevents galling and may be mixed with solid lubricant particles.
• an anodization process for forming a composite polymer-metal oxide film on a metallic substrate, such as aluminum.
• the process includes the steps of anodizing the metallic substrate, thereby forming an anodic film, and simultaneously depositing a polymer within the anodic film.
• the anodizing and depositing steps employ an electrolyte including an intrinsically conductive polymer, such as sulfonated polyaniline, and a protonic acid solution as an oxidizing agent.
• metal oxide formation is required.
• the composite polymer-metal oxide film can be formed on other metal substrates aside from aluminum, such as copper, steel, silicon, zinc, magnesium, or titanium.
• iron and carbon steel are not suitable metal substrates for the process of Runge-Marchese et al.
• polyaniline by itself is a lubricant that shows good anti-galling properties and also protects from corrosion, it acts synergistically with molybdenum disulfide in terms of anti-galling protection. Accordingly, in one embodiment according to our invention, described more fully later, polyaniline is combined with molybdenum disulfide in a surface composite.
• the invention makes use of intrinsically conductive polymers, previously described as a corrosion protection agent, as non-oily and non-liquid organic lubricants for metal surfaces.
• a method for protecting a metal surface from galling and corrosion includes a step of applying a dry film comprising a binding intrinsically conductive polymer to the metal surface.
• the intrinsically conductive polymer itself has lubricant properties and is capable of binding solid lubricants to the metal surface.
• the invention provides, in another aspect, a composition for protecting a metal surface from galling and corrosion.
• the composition includes a binding intrinsically conductive polymer with lubricant properties, and a solid lubricant.
• a surface treatment comprises the deposition onto a metal surface of a dry film including polyaniline, the polyaniline having lubricating properties and acting as a binding agent for molybdenum disulfide.
• the dry film may contain high amounts of the molybdenum disulfide, for example, in a proportion of four times the polyaniline by mass.
• the surface treatment may include pretreatment of the metal surface through chemical deposition of a conversion coating (that is, a coating that chemically changes the surface of a metallic part) such as, for example, manganese phosphate, zinc phosphate, oxalate, and the like; or chemical deposition of a copper layer onto high chromium alloy.
• Electrodeposition can be obtained by applying a suitable (electrode) potential to the metal surface immersed in an electrolytic aqueous solution containing aniline/monomer.
• the molybdenum disulfide can be entrapped in a polyaniline/polymer film by electrophoretic deposition of the lubricating mixture onto the metal surface.
• Additives may be included in the dry film in order to enhance properties such as anti-corrosive properties, high stability of the polyaniline-molybdenum disulfide mixture, or improved adherence of the dry film.
• the properties of the dry film can also be modified by post-chemical treatment.
• FIG. 1 is a cross-sectional view of the set-up of a ring-on-disk test.
• FIG. 2 shows an enlarged cross-section of part of the set-up of FIG. 1.
• FIG. 3 is a graph of a typical result of a ring-on-disk test
• FIG. 4 is an SEM image of a sliding surface, showing severe galling after a ring- on-disk test.
• FIG. 5 is an SEM image, taken after a ring-on-disk test, of the sliding surface of a phosphated disk treated with dry film (polyaniline + MoS 2 ).
• FIG. 6 is an SEM image, taken after a ring-on-disk test, showing detail of the sliding surface of a phosphated disk treated with dry film (polyaniline + MoS 2 ).
• the present invention relates to composition, preparation, and application of a dry film to steel and other metal surfaces, such as the surface of a threaded joint in an oil pipe, in order to protect the metal against galling under high applied torque, as well as to confer resistance to corrosion.
• the dry film of the invention comprises a solid lubricant selected from those commonly used for lubrication purposes, such as molybdenum disulfide, graphite, or mixtures thereof; and a binding intrinsically conductive polymer such as polyaniline, polyprrole, or copolymers or modifications of these polymers.
• Polyaniline used in the dry film may be prepared according to various methods, such as those described by Ponzio et al. (Polym. Int 50 (2001) 1180-1185), Cao et al. (Polymer 30 (1989) 2305-2311), Stejskal et al. (Synth. Met. 105 (1999) 195-202), Sun et al. (Synth. Met. 84 (1997) 99-100), Mattoso et al. (Synth. Met. 68 (1994) 1-11), Singh et al. (Polymer 38 (1997) 4897-4902), U.S. Patent No. 5,519,111 to McDiarmid et al, and U.S.
• Patent No. 5,567,355 to Wessling et al. A survey of methods of synthesis of polyaniline and its properties is reported by Genies et al. in Synth. Met. 36 (1990) 139- 182, and a standardized test protocol for preparation of polyaniline is reported by Stejskal et al. in Pure Appl Chem.74 (5) (2002) 857-867.
• Modified polyaniline can also be used for preparation of the dry film. Modification may be carried out on the polymer, both in the ring (Yue et al., J. Am Chem. Soc. 113 (1991) 2665-2671) and in the nitrogen (Hwang et al. Synth. Met. 92 (1998) 39- 46). Further, it is possible to polymerize a chemically-modified monomer or a mixture of monomers to obtain copolymers (see, for example, Mattoso et al., Synth. Met. 68 (1994) 1-11).
• a solid lubricant is not necessary in the dry film.
• a conducting polymer such as polyaniline
• polyaniline has lubricating or anti-galling properties as well as anti-corrosion properties.
• a simple polyaniline prepared and applied onto a metal surface in a manner according to the invention provides a lubricating coating that performs comparably or even better than many conventional oils.
• the dry film does not pose the leakage problems associated with conventional oils. Nor does it contain heavy metals (such as lead), which oils often have, that are harmful to the environment.
• the dry film has polyaniline in its emeraldine base form as the intrinsically conductive polymer, and molybdenum disulfide as the solid lubricant, in a 1 :4 to 1 :2 weight ratio.
• the best performance can be achieved by dissolving these components in fifty parts by weight of N-methylpyrrolidone (NMP) solvent.
• NMP N-methylpyrrolidone
• This liquid composite is then sprayed over a cleaned metal surface to be treated. Once the metal surface is dry, another layer of liquid composite may be applied, and best results are obtained by applying about 5 to 20 twenty layers of the composite by repeating the process described.
• the typical thickness of the dry supported lubricant film is about 1 to about 2 micrometers per layer of applied liquid composite, depending on the concentration of intrinsically conductive polymer in the liquid composite.
• the dry film does not require additives to help achieve protection against galling and corrosion.
• additives like dispersing agents for the solid lubricants or agents for stabilizing highly concentrated polymer solutions, are not excluded.
• Other agents may be a complementary inhibitor added to improve corrosion resistance, and a surfactant added to stabilize a suspension of the solid lubricant.
• possible additives may also include, for example, an agent for improving compatibility of a monomer and a solid lubricant in a particular solvent.
• the dry film may be applied to metal surfaces by any physical method for deposition of a liquid composite, such as application by spray or by painting with a brush.
• the film may also be applied by electrophoresis, as well as electropolymerization of monomers (or mixtures of monomers) in the presence of a solid lubricant or mixtures of solid lubricants.
• the liquid composite is applied by spray, which has an advantage of producing more homogeneous films and lends itself to use in field application and inclusion in a repair kit.
• the dry film may be applied onto a bare metal surface such as iron, steel, or stainless steel. It can also be applied, for example, onto a copper layer or a manganese phosphate layer previously deposited onto a metal surface. When one of the surfaces involved in a joint or in a friction couple ("pin and box" in the oil industry) is chemically pretreated by manganese phosphate, higher galling resistance has been observed. In the case in which the dry film is provided by electrodeposition, manganese phosphate and the conducting polymer layer may be co-deposited, or simultaneously grown.
• the dry film is applied to the surface of a box (that is, the internal female threaded end of a connection) pre-treated with manganese phosphate.
• the corresponding pin that is, the external male threaded end of a connection
• polyaniline only
• Polyaniline (or polypyrrole) is first prepared by chemical polymerization of aniline (or pyrrole) with sodium persulfate as an oxidant in the presence of sulfuric or phosphoric acid.
• the polyaniline which will be in its emeraldine oxidation form (protonated or salt form), is filtered.
• the green powder is then re-suspended in a stirred solution of ammonium hydroxide for a few hours, after which the solution is filtered again and the dark blue polymer (emeraldine base form) is dried until no water remains.
• High reaction yields of over about 70%, are obtained.
• Solid lubricant may be added to the polymer solution with continuous stirring during the addition.
• the mass of lubricant is adjusted so that it is in about a 1 :4 ratio by weight in relation to the polymer, or about 2% to about 10 % by weight in relation to the solvent.
• FIGS. 1 and 2 depict schematics of a "ring-on-disk" test layout.
• Reference numeral 10 denotes an electric motor that applies rotation to a ring-shaped part (24 in FIG. 2) at a given speed.
• Reference numeral 20 corresponds to a ring-and-disk sample set being evaluated: the sample comprises the ring-shaped part 24 (FIG. 2) and a discshaped lower part (26 in FIG. 2).
• Reference numeral 30 denotes a torque load cell which is a device used to measure the resultant torque;
• reference numeral 40 denotes an axial load cell that measures applied axial load;
• reference numeral 50 denotes a hydraulic piston employed to apply a controlled axial load (22 in FIG. 2 denotes an axis of load application).
• the dried film can be applied by either physical deposition of the liquid composite or by electrochemical or electrophoretic techniques.
• the ring-on-disk test consisted of monitoring torque over time.
• FIG. ' 3 is a graph of a typical test result.
• the applied pressure between ring and disk was increased up to 30 Kg/mm 2 and after that was kept constant.
• the torque value increased with the applied pressure.
• the torque value decreased and then remained almost constant, indicating a good lubrication process.
• galling occurred sharp fluctuations in torque value were observed.
• the time that elapses until the fluctuations begin is considered the characteristic time for the test.
• FIGS. 4 is a scanning electron micrograph (SEM) image of a sliding surface, not treated with the dry film, showing severe galling after a ring-on-disk test.
• FIGS. 5 and 6 are SEM images, taken after a ring-on-disk test, of the sliding surface of a phosphated disk treated with dry film (polyaniline + MoS 2 ). No galling was observed even after several hours of testing.
• Table 1 shows that direct application over steel surfaces pretreated with manganese phosphate results in similar or better performance than applying commonly- used oily liquid lubricants.
• N° M&B number of make-up and break-out cycles. a) Where the entry in the Galling column is "Yes", the N° M&B number indicates the cycle during which galling took place. b) Where the entry in the Galling column is "NO”, the N° M&B number indicates the number of cycles that elapsed, with no evidence of galling, before testing was stopped.
• Entries in the M&B Required column refer to the number of make-up and break-out cycles without galling required by the ISO 13679 standard.
• This invention provides a method for protecting a metal surface from galling and corrosion, and a composition for protecting a metal surface from galling and corrosion.
• the method and the composition can preferably be applied, for example, to any type of metal thread and any type of metal oil-pipe joint commonly used in the oil industry, in order to confer resistance to galling and corrosion in a simple and economical manner.

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