EP1280942A1 - Systeme de protection de surfaces sous-marines - Google Patents

Systeme de protection de surfaces sous-marines

Info

Publication number
EP1280942A1
EP1280942A1 EP01932774A EP01932774A EP1280942A1 EP 1280942 A1 EP1280942 A1 EP 1280942A1 EP 01932774 A EP01932774 A EP 01932774A EP 01932774 A EP01932774 A EP 01932774A EP 1280942 A1 EP1280942 A1 EP 1280942A1
Authority
EP
European Patent Office
Prior art keywords
zinc
coating
metal
marine
thermal spray
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01932774A
Other languages
German (de)
English (en)
Inventor
Edwin Call
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Power Spray Inc
Original Assignee
Power Spray Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Power Spray Inc filed Critical Power Spray Inc
Publication of EP1280942A1 publication Critical patent/EP1280942A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
    • B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
    • 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
    • C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
    • C23C4/04—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge characterised by the coating material
    • C23C4/06—Metallic material
    • C23C4/08—Metallic material containing only metal elements

Definitions

  • the invention is a system comprised of metallized coatings and thermal spray procedures that produces a unique protective coating, i particular, the invention consists of preparing and applying zinc and zinc-based alloys. These materials are thermal sprayed with unique metallizing processes and procedures onto surfaces of submerged marine structures. This invention differs from other metallized coatings in that it performs the function of bio-fouling protection and cathodic protection.
  • thermal spray coatings are often called metallized coatings. Many metals and alloys exist; aluminum and zinc are the most widely used metals for corrosion control.
  • Aluminum metallized coatings (AMC) and zinc metallized coatings (ZMC) provide long-term corrosion protection for greater than 30 years. Compared to paint, both AMC and ZMC have superior corrosion and abrasion resistance.
  • Aluminum and zinc are anodic to most metals and protect these more noble substrates in electrolytic environments. Aluminum is more noble than zinc; therefore, it corrodes less rapidly than zinc. As a result, aluminum metallized coatings are more commonly used for corrosion protection in marine environments, rather than zinc metallized coatings. This is especially the case for immersion applications. Since the aluminum metallized coating will corrode less rapidly than zinc, AMC has been the standard choice for submerged, splash zone, and above water marine applications.
  • Thermal spray coatings have been used for corrosion protection on steel structure since the early 1900's. More recently, zinc metallized coatings are applied directly to the reinforced concrete surface to prevent future corrosion of the rebar. Highway bridges , parking garages, and other concrete structures can be protected using these (CP) cathodic protection systems.
  • Zinc is the choice metal for cathodic protection, because it is one of the least noble metals and is compatible with concrete. When zinc is in bimetallic contact with steel in an electrolyte, the zinc will corrode or "sacrifice itself and provide a level of protection to the more noble metal. The contact may be direct or indirect.
  • TBT tributyltin
  • Butyltins are organic tin compounds. Tributyltin is a butyltin compound.
  • TBT paint is applied to ship hulls and ship components, the TBT leaches or "dissolves" into the water. When it settles to the bottom of the water table, it poisons and may kill marine life. Strong scientific evidence links TBT to adverse biological effects in fish and shellfish. Recent studies indicate that TBT and other butyltin compounds are causing deaths in sea mammals.
  • TBT paints have provided a solution to boat owners but at an extreme expense to the environment, marine life and possibly humans.
  • the environmental and health hazards of TBT are issuing a call for alternatives, and the political response to ban the use of TBT in marine paints creates a demand for proven antifouling coatings without environmental hazards.
  • the present invention contains no pesticides, biocides, or tributyltin. Since this product is a thermal spray coating, it contains no solvents or volatile organic compounds (NOCs). This is an important distinction from anti-fouling paints. Most of the solvents in these paints contain chemicals that are listed by the US Environmental Protection Agency as a hazardous material. Therefore, the production and use of these paints requires adherence to strict regulations because of the risk to health and safety of humans. When applied, liquid solvents in the paint coating evaporate. These solvents which contain NOC pose dangers to the atmosphere by ozone depletion. Furthermore, the containment, handling and disposal of the used paint cans and byproducts of the application process create several environmental problems.
  • This invention includes the use of zinc-based metallized coatings to present hard fouling on submerged surface.
  • Zinc-copper is one of the alloys selected for this invention. It can be stated, however, that the release rate of zinc, or copper or any of the metals on alloys used to form a metallized coating is much lower than that of a paint product, because the copper metal is only being released through oxidation. Paints contain copper salts that are soluble in water. Metallized coatings produced by this invention are insoluble in water. In fact, the metals or alloys used in this invention and thermal spray processes are insoluble in water.
  • the primary purpose of this invention is to protect surfaces of submerged marine structures from bio-fouling and more particularly, hard fouling such as from barnacles. More particularly, the present invention relates to a process for the protection of submerged marine structures in need of protection against hard fouling, such as barnacles because of the environment in which such marine structures are placed, for example in salt water.
  • a second aspect of the invention relates to cathodic protection.
  • a 100% metal coating is applied directly to the substrate.
  • the coating is applied using a thermal spray process.
  • the term metallizing is often used instead of thermal spray.
  • the two terms are interchangeable.
  • the present invention contains no solvents or volatile organic compounds (NOC).
  • NOC volatile organic compounds
  • the coating is a zinc or zinc- based alloy.
  • the coating is not designed as an ablative coating or self-polishing coating like other marine paints; therefore, minimal leaching of the coating into the water table occurs.
  • the purpose of this invention is to provide a coating system that performs better and is more desirable environmentally than conventional paint systems that contain toxins or heavy metals.
  • the coating of the present invention is comprised of zinc and zinc-based alloys. It contains no tributyltin (TBT), volatile organic compounds (NOC), pesticides, or biocides.
  • the coatings of this invention are intended to perform in conjunction with and more efficiently than other cathodic protection systems that require external electrical power supplies or sources.
  • the present invention involves no external power supplies; therefore it involves less maintenance and repair than electrically impressed protection systems.
  • An advantage of this invention is that the coating can be sprayed directly to the substrate. It provides a system more feasible and cost-effective than spraying copper-nickel to a resin insulating layer. Thermal sprayed zinc and zinc based alloys provide a more durable coating than a copper-nickel and resin coating system, because a metal-to-metal bond is stronger than a metal-to-resin bond.
  • the present invention is a zinc-based coating sprayed directly to the surface of the marine structures and surfaces.
  • the surface to be protected by this invention can be any surface which needs protection from fouling, including but not limited to steel, aluminum, brass, stainless steel, concrete, fiberglass, plastic, and wood.
  • the present invention provides a cost-effective way to perform all stated functions, essentially to provide a commercially feasible application process for industries including, but not limited to, pleasure craft, oil and gas, power generation, shipping, petro chemical, paper and pulp, aids to navigation, and water treatment facilities.
  • the present invention provides protection for structures, including, but not limited to ship hulls and boat hardware (propellers, rudders, shafts, trim tabs, strainers, etc.), buoys, locks, dams, off-shore oil rigs, piers, wharfs, bulk heads, pipelines, seawater intakes.
  • this invention avoids the problems associated with other coating systems.
  • Current bio-fouling control techniques cause galvanic corrosion of the coated metal structure.
  • the present invention avoids galvanic corrosion problems caused when placing dissimilar metals like copper on or near steel or aluminum.
  • the steps, methods, and components of the invention are illustrated as follows.
  • the surface metal is power washed with fresh, clean water to remove soluble salts and bulk biomass.
  • the metal surface is blasted to a suitable extent; for example to a white metal according to standard SSPC-SP-5.
  • a suitable anchor-tooth profile is created for a thermal spray coating.
  • non-metal surface such as concrete, fiberglass, plastic, composites, etc., other blasting techniques are required.
  • a zinc-based metal wire is selected that is compatible with the substrate.
  • the coating is then applied using a thermal spray process such as electric arc, combustion wire, or combustion powder. Electric arc is preferred. Uniform coverage is achieved by applying multiple layers of the coating and overlapping passes with the spray gun. A sealer may be added to the thermal spray coating to provide additional benefits. Sealers for thermal spray coatings are used by those familiar with the art.
  • the zinc-based metal wire is composed of 50-100% zinc. The remaining metals include, but are not limited to, copper, carbon, tin, nickel, aluminum, and magnesium.
  • the present invention involves the spraying of zinc-based alloys, it avoids the toxic problems associated with tributyltin paints and copper paints.
  • zinc does not create galvanic corrosion when sprayed on steel or aluminum structures.
  • the following metals are the most commonly used in the manufacture of marine structures or vessels: nickel, brass, bronze, stainless steel, and copper-nickel.
  • zinc provides cathodic protection to submerged metallic marine structures.
  • a preferred method is to modify standard thermal spray procedures.
  • the purpose of the modifications is to produce a harder and more durable coating when compared to normal corrosion control coatings and to produce superior protection against bio-fouling with the added bonus of cathodic protection.
  • Thermal spray industry standards for air pressure and spray parameters such as spray voltages have been elevated to provide a coating that is better as an anti-foulant than other thermal spray coatings.
  • the modification of industry standards improves the anti-fouling characteristics of the invention.
  • Another preferred method is to select thermal spray equipment that produces a spray of small particles.
  • the inventor has found that spraying small particles produces a smoother and more desirable coating.
  • the inventor has discovered that using equipment that sprays large particles can cause a courser, uneven coating.
  • the technique and skill of the thermal spray technician is important to the quality of the coating.
  • the inventor prefers the use of an electric-arc, twin wire system for applying the coating.
  • one of the wires may be zinc and the second wire can be zinc or copper, aluminum, tin, nickel or magnesium.
  • copper is known to have anti-fouling characteristics.
  • copper and copper-nickel alloys may create electrolysis problems. Copper and copper- nickel alloys will cause galvanic corrosion to aluminum and steel when the coating is damaged and exposes the less noble substrate in an electrolytic environment.
  • the inventor's use of zinc and zinc-based alloys provides a better coating than copper and copper-nickel alloys for two reasons. First, zinc and zinc-based alloys are compatible with more surfaces than a copper or copper-nickel alloy. Second, in tests conducted by the inventor it was demonstrated that zinc metallized coatings performed better than copper metallized coatings. Performance was rated by ability to prevent hard fouling.
  • the present invention is durable in harsh marine environments. Resin-based paints craze and crack badly when left in the sun for an extended period of time, hi addition, the antifouling characteristics of traditional point coatings are lost if the pain remains out of water for extended periods of time (30-90 days). Most resin-based paints use copper or cuprous-oxide as the active anti-fouling agent. Ultraviolet for extended out of water have no negative effect on the performance of zinc or zinc-based metallized coatings in accordance with the present invention.
  • the present invention also acts as a passive cathodic protection system. Since the invention is passive, it is easier to maintain and more economical than an impressed current cathodic protection system. It contains no expensive power supplies, reference cells, wiring, etcetera. The complexity of an active cathodic protection system makes it more expensive and less reliable for the owner of the marine structure.
  • the coating system of the present invention protects surfaces of submerged marine structures, such as ship hulls, from bio-fouling with the additional characteristic of cathodic protection. Not only does the invention provide improved performance when compared to existing paint systems, the design is also cost-effective and commercially feasible. No insulating layers of paint are required with this invention.
  • the zinc or zinc- based thermal spray coating can be applied directly to the substrate of the structure; therefore, it is more economical because it has fewer application steps.
  • the cathodic protection characteristics of this invention will also provide the owner of the vessel or structure with the added benefit of life-cycle cost savings by reducing the corrosion rate and consumption of zinc anodes. For example, structure owners routinely place zinc anodes on underwater metal surfaces to protect the dissimilar metal from corrosion.
  • This invention when applied to components or sections of the structure will reduce the consumption rate of the structure's zinc anodes. In this event, the zinc metallized coating or zinc-based metallized coating works in concert with the zinc anodes. Certain outside factors uncontrolled by this invention may prevent this benefit. They include but are not limited to the amount of stray electrical current present on the vessel, the level of stray electrical fields in the surrounding water, and the manner in which electrical devices on or near the structure are wired.
  • This invention provides an entire coating system for cathodic protection.
  • Foui- carbon steel supports for the dive platform were coated. Since aluminum is the preferred metal for marine underwater corrosion protection, thermal sprayed aluminum was applied to all the supports except one which was coated with thermal sprayed zinc.
  • Example 2 Thermal sprayed zinc and zinc-based alloys were applied to aluminum propellers, brass propellers, aluminum samples, steel samples, and brass samples. Some propellers were placed on boats and others were placed in saltwater rivers and bays tributary to the Chesapeake Bay and Atlantic Ocean. It was concluded from these tests that zinc and zinc-based thermal spray coatings protect the base metal from bio-fouling, and galvanic corrosion.
  • a three-bladed brass propeller was coated with a copper/zinc metallized coating.
  • the propeller was hung into a saltwater tributary to the Chesapeake Bay.
  • the propeller remained in the water for one full season (approximately four months).
  • the propeller was pulled out for analysis.
  • a garden hose was used to remove the soft fouling on the propeller.
  • the propeller had no barnacle growth or other hard fouling.
  • the tips of two of the propeller blades were cut off and submitted to a laboratory for analysis. The purpose of the analysis was to determine if the substrate was protected from corrosion.
  • the laboratory took sections from the blade tips for analysis. These sections were mounted in epoxy resin and then polished. Using microscopy, the laboratory found that "there was no apparent attack or disorder in the parent metal.”
  • Two 2" x 2" metal pieces were coated.
  • the first piece was aluminum coated with a zinc metallized coating.
  • the second piece was a brass piece coated with a copper-zinc metallized coating.
  • These two samples were placed on string and hung alongside a dock.
  • a third uncoated carbon steel sample was hung in the water with the coated samples.
  • the dock is located on a saltwater creek that feeds into the mouth of the Chesapeake Bay. These three samples were exposed for one summer season (approximately four months).
  • test float was placed at the same marina location mentioned in the above examples.
  • the test float was made out of PNC piping. Twenty-six 2" x 2" metal samples were tied to the float using nylon string. The samples were made of steel, aluminum, brass, or stainless steel. Seven different metallized coatings were coated on each type of metal. The coatings included a zinc metallized coating and six zinc-based alloy metallized coatings. One uncoated sample of each metal was tied to the float as well. The results of the tests are as follows:
  • the zinc metallized coating performed well on all substrates.
  • the six zinc-based coatings varied in performance. .
  • Example 6 Two 24" 3-bladed Propellers 1998 - 2000
  • two three-bladed propellers were coated for a boat docked on the Elizabeth River in Norfolk, Virginia.
  • the owner of the boat uses the boat infrequently, so the propellers are often sitting still for several weeks at a time.
  • barnacles strike on metal and need time to adhere to the surface. If a boat is used regularly, then the barnacles are swept off the metal surfaces by the action or forward motion of the boat. This boat was moored at the dock in Elizabeth River for two years. In December 2000, the boat was hauled out for the first time since November 1998.
  • the propellers were free from heavy fouling except for a few small barnacles around the hub of the propeller. Under normal conditions, the owner stated that the propellers would have been entirely coated with barnacles. Due to the customer's satisfaction with the results, he asked the inventor to apply the same metallized coating to the boat shafts, struts, rudders and trim tabs. The inventor mobilized a crew to the boat yard and provided the service.
  • Example 7 Zinc anodes on two shafts connected to two 24" 3-bladed propellers (same propellers as described in Example 6)
  • the boat described in Example 6 is not only an example of the anti-fouling characteristics of the invention, it is also an example of the cathodic protection provided by the invention.
  • the shafts on this boat were stainless steel.
  • the propellers were brass.
  • the zinc anodes on the shaft of this boat were in excellent condition after two years of use. The anode held its original shape and was only slightly depleted. The boat owner stated that prior to 1998 and under the same marina conditions, the boat's anodes would be completely depleted in less than two years.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Plasma & Fusion (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Coating By Spraying Or Casting (AREA)
  • Prevention Of Electric Corrosion (AREA)

Abstract

L'invention concerne un procédé permettant de protéger des surfaces sous-marines contre le bio-encrassement, qui consiste à pulvériser sur ces surfaces à un revêtement en alliage à base de zinc ou en zinc sans solvant produit par un procédé de pulvérisation thermique.
EP01932774A 2000-05-02 2001-05-01 Systeme de protection de surfaces sous-marines Withdrawn EP1280942A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US20130600P 2000-05-02 2000-05-02
US201306P 2000-05-02
PCT/US2001/013924 WO2001083842A1 (fr) 2000-05-02 2001-05-01 Systeme de protection de surfaces sous-marines

Publications (1)

Publication Number Publication Date
EP1280942A1 true EP1280942A1 (fr) 2003-02-05

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP01932774A Withdrawn EP1280942A1 (fr) 2000-05-02 2001-05-01 Systeme de protection de surfaces sous-marines

Country Status (3)

Country Link
EP (1) EP1280942A1 (fr)
AU (1) AU2001259275A1 (fr)
WO (1) WO2001083842A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6598581B2 (en) * 2001-12-13 2003-07-29 Visteon Global Technologies, Inc. Metallic coating on a component of an internal combustion engine
AU2003224044A1 (en) * 2002-04-11 2003-10-20 Grillo-Werke Ag Method for connecting parts
AU2003221556A1 (en) * 2002-04-11 2003-10-20 Grillo-Werke Ag Method for improving the properties and/or protection of wood surfaces
FR2869917B1 (fr) * 2004-05-10 2009-08-21 Daniel Bernard Materiaux de construction constitues d'une base de beton, de ceramique terre cuite ou de bois sur laquelle est juxtaposee une pellicule de metal polie
FR3011837A1 (fr) * 2013-10-11 2015-04-17 Daniel Bernard Materiaux de construction avec traitement anti-mousses et lichens

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3497434A (en) * 1967-07-20 1970-02-24 Lockheed Aircraft Corp Method for preventing fouling of metal in a marine environment
JPS61124679A (ja) * 1984-11-22 1986-06-12 株式会社クラレ 水中生物付着を軽減した有機繊維複合材料
US4992337A (en) * 1990-01-30 1991-02-12 Air Products And Chemicals, Inc. Electric arc spraying of reactive metals

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO0183842A1 *

Also Published As

Publication number Publication date
AU2001259275A1 (en) 2001-11-12
WO2001083842A1 (fr) 2001-11-08

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