thermal spray coating - ltrc.lsu.edu€¢during metallizing operations, a wire is fed through a gun...
TRANSCRIPT
![Page 1: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/1.jpg)
Thermal Spray Coatingfor Corrosion Protection
Presented by:John Crowe, PCS
What You Need To Know
![Page 2: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/2.jpg)
PRESENTATION TOPICS
• Corrosion Basics
• Thermal Spray Coating-What It Is & What It Does
• Advantages & Disadvantages
• Basics for Good Application
• Steel Bridge Metallizing Case Studies
• Metallizing of Concrete Substructures
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 3: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/3.jpg)
CORROSION BASICS
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 4: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/4.jpg)
CORROSION
“The destruction of a material by chemical or more specifically, electrochemical reaction with its
environment.”
FOR OUR PURPOSES:
The destruction of steel resulting in the formation of rust
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 5: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/5.jpg)
NATURAL CYCLE OF CORROSIONTHERMAL SPRAY COATING FOR CORROSION PROTECTION
Iron Ore
Steel (Iron) Plate
Blast Furnace
Exposure
Corrosion/Rust
![Page 6: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/6.jpg)
FOUR CONDITIONS NECESSARY FOR CORROSION (ACME)
• Anode
• Cathode
• Metallic Pathway
• Electrolyte
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 7: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/7.jpg)
COATINGS DECISIONS BASED ON CORROSION CYCLE
THERMAL SPRAY COATING FOR CORROSION PROTECTION
% Corrosion
Time
Touch-up / Spot
Repair w/Overcoat
Complete Replacement
3-5%
6-10%
>20%
![Page 8: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/8.jpg)
METHODS OF PROTECTION
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 9: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/9.jpg)
METHODS OF PROTECTION
• PROTECTIVE COATINGS• Conventional Liquid Coatings:
• Barrier• Inhibitive• Sacrificial
• CATHODIC PROTECTION• Impressed Current• Sacrificial Galvanic
• ALTERNATIVE MATERIALS• Alloys (Stainless Steel, Brass)• Composites• Aluminum
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 10: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/10.jpg)
HOW PROTECTIVE COATINGS WORK
• Barrier Coatings• Most liquid coatings work this way. They provide a semi-permeable
barrier to air and moisture that provides a barrier to environmental exposure.
• Inhibitive Coatings• Some coatings passivate the steel to prevent corrosion. • Conversion coatings (phosphoric acid and chromate washes) and
calcium sulfonates work this way.
• Galvanic (Sacrificial) Coatings• Coatings give off electrons and sacrifice themselves for the substrate.
Zinc and lead based coatings work this way.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 11: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/11.jpg)
GALVANIZING
• Galvanizing works primarily as a sacrificial coating. As it does it’s job, the zinc coating gives up electrons which react with the environment leaving the characteristic white powder, which is actually zinc salts.
• Galvanizing also works as a barrier coating.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 12: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/12.jpg)
WEATHERING STEEL
• Weathering steel is actually steel which is specially formulated to corrode SLOWLY. In ideal situations this corrosion is imperceptible, however it forms a protective “patina”.
• In environments where weathering steel is subject to frequent wetting, it will corrode quickly. In applications like Interstate overpasses, this frequent wetting and chlorides will accelerate corrosion, ultimately leading to section loss, and premature failure.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 13: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/13.jpg)
THERMAL SPRAY COATING (METALLIZING)
• Metallizing is the application of molten metal to a prepared steel surface for the purposes of cathodic corrosion protection. It is a sacrificial galvanic coating.
• Metallizing is also used as a form of cathodic protection on concrete structures, when connected to the reinforcing steel.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 14: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/14.jpg)
METALLIZING – HOW IT WORKS
• Unlike most organic liquid coating systems, which primarily provide barrier protection; metallizing provides corrosion protection through sacrificial galvanic action. Metallizing provides protection to the steel, and will act as a sacrificial anode, similar to that in a water heater or outboard motor.
• Galvanizing utilizes the same primary corrosion protection mechanism. Unlike galvanizing, metallizing is porous in nature, and should be sealed to provide maximum service life.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 15: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/15.jpg)
METALLIZING – HOW IT IS APPLIED
• During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air.
• Metallizing can be applied by flame spray or electric arc methods.
• The most common Metallizing wires consist of either pure Zinc (Zn), pure Aluminum (Al) or a 85/15 Zn/Al mix.
• The use of 85/15 Zn/Al is most common due to it’s workability and higher adhesion capabilities than pure zinc.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 16: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/16.jpg)
METALLIZING – HOW IT IS APPLIEDTHERMAL SPRAY COATING FOR CORROSION PROTECTION
Arc-spray system
Flame spray system Powder spray system
![Page 17: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/17.jpg)
METALLIZING – HOW IT IS APPLIEDTHERMAL SPRAY COATING FOR CORROSION PROTECTION
ARC–SPRAY SYSTEM
![Page 18: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/18.jpg)
METALLIZING – HOW IT IS APPLIEDTHERMAL SPRAY COATING FOR CORROSION PROTECTION
Typical Metallizing Operation
![Page 19: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/19.jpg)
ADVANTAGES OF METALLIZING
• Long Service Lifeo Some applications have been in service 50+ years.
• Superior Life Cycle CostoDue to the long service life and reduced interim maintenance.
• Cold Weather FriendlyoUnlike most coating systems, metallizing can be applied at any
temperature.
• No curing periodoMetallizing does not require any time to cure or recoat, allowing the
entire thickness to be placed in a single work shift.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 20: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/20.jpg)
DISADVANTAGES OF METALLIZING
• Higher initial cost.
• Requires higher degree of surface preparation.
• Requires removal of flame hardening and other surface defects for good success.
• Less user friendly and requires highly trained and experienced operators.
• Requires a sealer for maximum performance.
• May incorporate the use of an aesthetic overcoat.
• May be affected by some liquid deicing compounds.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 21: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/21.jpg)
BASICS FOR GOOD APPLICATION
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 22: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/22.jpg)
SURFACE PREPARATION
• SURFACE PREPARATION – SSPC-SP5, “White Metal Blast”
• CHLORIDES - Remediate to less than 5 µg/cm²
• SURFACE PROFILE - 2.5 to 4.5 mils
• ABRASIVE - Use expendable abrasive to avoid peening, and produce a sharp, angular profile
• FLAME CUT EDGES - Remove flame hardening through grinding prior to abrasive blasting
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 23: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/23.jpg)
THERMAL SPRAY APPLICATION
• APPLICATORS - Use trained & experienced operators. Consider daily bend tests. Standoff distance and angle of application are critical.
• APPLICATION - Should be made as soon after blast as possible to avoid flash rusting and/or rustback.
• BUILD - Apply full 8 to 12 mils in a single shift to avoid intercoat cleanliness & adhesion problems. Apply in multiple passes of 2 mils each.
• ADHESION - Should be a minimum of 700 psi for 85/15 Zinc/Aluminum metallizing.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 24: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/24.jpg)
SEALER APPLICATION
• USE - Sealer should be applied to 100% of the metallized area.
• THICKNESS - Sealer is meant to fill voids in metallizing, and not intended as a barrier coat. Application thickness 0.5 to 1.5 mils.
• TIME - Sealer should be applied within 8 hours of thermal spray application to ensure good penetration into metallizing.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 25: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/25.jpg)
STEEL BRIDGE METALLIZING CASE STUDIES
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 26: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/26.jpg)
CASE STUDY NO. 1
Cleaning and metallizing of the Rainbow Bridge, Niagara Falls, NY
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 27: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/27.jpg)
THE PROJECT
• The project involved complete coatings removal and metallizing of the Rainbow Bridge, crossing the Niagara River Gorge from Niagara Falls, US to Niagara Falls, Canada.
• Tourism and pedestrian use dictated coatings work to progress during winter months.
• Aesthetic moisture cure polyurethane (MCU) overcoat applied due to highly visible nature of the structure.
• Work performed from 2002 – 2004.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 28: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/28.jpg)
SPECIFICATION
• Specified 85/15 ZN/AL metallizing, at 8 to 12 mils thickness.
• SSPC SP5, “White Metal Blast” was specified - expendable abrasive was required.
• Chloride remediation was 5 µg/cm².
• Metallizing was applied in a single shift.
• An MCU Sealer was specified, and applied within 8 hours of metallizing application.
• Minimum adhesion allowed was 700 psi.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 29: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/29.jpg)
IN SERVICE PERFORMANCE
• Metallizing is performing as well as anticipated after a 15 year evaluation.
• Problem areas were limited to isolated areas of deck/joint leakage.
• MCU overcoat may be needed in visible areas.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 30: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/30.jpg)
LESSONS LEARNED
• Metallizing can be cost effective (life cycle cost) in large applications, when properly performed.
• MCU sealers and overcoats work well.
• Metallizing was successfully applied in winter months under the appropriate conditions.
• Access to properly trained and qualified metallizing applicators is key.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 31: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/31.jpg)
CASE STUDY NO. 2
Rehabilitation and Recoating of the Stickney Point Bridge, Sarasota, FL
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 32: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/32.jpg)
THE PROJECT
• Project involved rehabilitation, steel repair and recoating of Stickney Point Bridge (SR 72), the main route into Siesta Key.
• Adjacent residences and tourism drove project schedule.
• Metallizing chosen to prolong coating life and maximize time to future repainting.
• First metallizing project on FL’s West Coast.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 33: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/33.jpg)
COATING SELECTION CRITERIA
• Metallizing:
• 50+ Years of corrosion protection
• Advances in portable metallizing equipment
• Decrease in future maintenance painting projects
• Ability to blast, metallize and seal in one shift
• Less restrictive ambient condition requirements
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 34: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/34.jpg)
SPECIFICATIONS
• Specifications Utilized:
• Florida DOT, Section 561, “Coating Existing Structural Steel”
• SSPC-CS 23.00/AWS C.2.23/NACE No. 12, “Application of Thermal Spray Coatings (Metallizing) of Aluminum, Zinc, and Their Alloys and Composites for the Corrosion Protection of Structural Steel.”
Note: TSP referenced CS-23 in it’s entirety, and only discussed those items that changed from joint standard.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 35: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/35.jpg)
SPECIFICATION ISSUES• Key Requirements/Issues
• Soluble salts
• Edges, connections, fasteners
• Blasting, metallizing, sealing and adhesion testing must be done in one shift
• Caulking
• Anchor profile
• Clear coat – after repairs, degradable dye
• Dry film thickness measurements –SSPC PA-2
• Removing hardened surfaces
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 36: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/36.jpg)
REQUIREMENTS FOR GOOD METALLIZING
• NACE No. 1 / SSPC-SP5, “White Metal Blast”
• Deeper Anchor Profile – Minimum 2.5 mils
• Contractor / Applicator Pre-Qualifications
• Adhesion Testing – ASTM D4541
• Flexibility – Mandrel Testing
• 8-12 Mils DFT, Multiple Passes, 3’ x 3’ Work Area
• Distance from the Substrate
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 37: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/37.jpg)
LESSONS LEARNED
• Not recommended for incentive/disincentive contracts, as changes are under restraint.
• Flame cut edges were an issue, even though addressed in Section 561. • Need to specifically identify in future.
• Limited number of contractors in FL became a potential issue when metallizer was removed by FDOT.
• Areas with limited access where metallizing may not be practical need to be identified and addressed in the contract.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 38: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/38.jpg)
METALLIZING OF CONCRETE SUBSTRUCTURES
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 39: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/39.jpg)
INTRODUCTION
• In other areas of the country, metallizing is used as a form of passive Cathodic Protection (CP) for concrete structures.
• Florida DOT uses this process extensively for their numerous coastal substructures. These methods may be applicable in LA.
Acknowledgement goes to Ivan Lasa, of FDOT Corrosion Research Laboratory for the use of the following slides:
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 40: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/40.jpg)
INTRODUCTION
• A thermal sprayed zinc anode applied can be used for steel or concrete.
• Provides corrosion protection on steel surfaces and corrosion control (CP) on concrete.
• Zinc, aluminum, 85/15 alloy is the most commonly used.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 41: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/41.jpg)
TYPICAL CORROSION OF REINFORCED CONCRETE
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 42: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/42.jpg)
REPAIRS ON CHLORIDE CONTAMINATED CONCRETE
• Why Cathodic Protection?oGood patches promote
accelerated corrosion in the concrete surrounding the patch and new spalls develop in a few years.
oCorrosion develops around the repair due to the characteristic change of the repaired rebar.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 43: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/43.jpg)
HOW IT WORKS
• Direct Connection• An electrical circuit is established such that current flows from the
external metallizing to the rebar.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 44: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/44.jpg)
SACRIFICIAL CATHODIC PROTECTION
• Arc-Sprayed Metallizingo Requires an electrical connection to the steel reinforcement, but can be
used without concrete restoration by application directly to the steel reinforcement.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 45: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/45.jpg)
CHANNEL FIVE BRIDGE
• Connection plates placed above the splash zone.
• Typical service life of the system is 10 to 12 years.
• 16 – 20 mils thickness (typical).
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 46: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/46.jpg)
HOWARD FRANKLAND BRIDGE
• Typically applied to caps and beams (most common use).
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 47: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/47.jpg)
BRIDGE DECK APPLICATION
• Metallizing on bridge underdecks provides a service life of 8 to 10 years depending on elevation of the underdeck (may be less).
• A top coat to reduce atmospheric corrosion is sometimes used.
THERMAL SPRAY COATING FOR CORROSION PROTECTION
![Page 48: Thermal Spray Coating - ltrc.lsu.edu€¢During metallizing operations, a wire is fed through a gun which melts the wire and propels it onto the surface utilizing compressed air](https://reader035.vdocuments.net/reader035/viewer/2022062909/5b2f20fc7f8b9a94168c6273/html5/thumbnails/48.jpg)
THANK YOU!!!
Questions?
THERMAL SPRAY COATING FOR CORROSION PROTECTION
[email protected](904) 652-1099