1. Coating Failure Analysis  An overview © KTA-Tator, Inc.

3. Coating Failure Consequences  Damage to substrate  Costly rework  Downtime  Product contamination

4. Coating Failure Consequences : Damage to Substrate  Substrate repair  Substrate replacement

5. Pedestrian Bridge Pedestrian Bridge

6. Coating Failure Consequences: Costly Rework  Condition of the existing system?  Field repairing a shop applied system

7. Coating Failure Consequences: Downtime  Can cost more than the coating failure

8. Examples areas where corrosion has developed and may be difficult to address. 5a– The surfaces above grating slots are below motor and lock pin assemblies. 5b– Grating strips and angle iron beneath sidewalk grating and curb. 5c– Corrosion above lift span girder below the steel curb over deck/sidewalk grating. 5d- Back to back angles of a counterweight. 5e– Rusted fasteners behind electric (latch pin) motor. 5f– Steel above a lift span girder -the underside of various steel elements deck surface. Examples areas where corrosion has developed and may be difficult to address. 5a– The surfaces above grating slots are below motor and lock pin assemblies. 5b– Grating strips and angle iron beneath sidewalk grating and curb. 5c– Corrosion above lift span girder below the steel curb over deck/sidewalk grating. 5d- Back to back angles of a counterweight. 5e– Rusted fasteners behind electric (latch pin) motor. 5f– Steel above a lift span girder -the underside of various steel elements deck surface.

9. SCRUB COLUMNS

10. Coating Failure Consequences: Product Contamination  Tanks, vessels, pipelines  Product contact with disbonded coating  Product contact with exposed substrate

11. Coating Failure Analysis  Receiving the “telephone call” (Background)  Field Investigation  Laboratory analysis  Report and Recommendations

12. Background  Location  Substrate  Age of Site and of Coating  Location,storage, or exposure of coating  Coating Specification  Coating Product Data Sheets  Coating Inspection

13. Background  Substrate preparation  Environmental conditions during coating application  Time reference between failure and application of coatings  Description of failure including any noticeable patterns

14. Field Investigation  View condition of the applied coatings  Investigate the nature of the failure  Dry film thickness of the coating  Field testing of coating; physical parameters  Condition of the substrate  Obtain samples from “failing” areas that are representative of the failure

15. Field Investigation  Obtain samples from “non-failing” areas that are representative  Note any patterns

16. Laboratory Techniques for Coatings Failure Analysis

17. Laboratory Testing  Optical / Digital Microscopy  Infrared Spectroscopy  Gas Chromatography / Mass Spectroscopy / Pyrolysis  High Performance Liquid Chromatography  SEM / EDS  Atomic Absorption Spectroscopy  Differential Scanning Calorimetry  Electrochemical Impedance Spectroscopy

18. Optical / Digital Microscopy  Visual examination of coating samples  20X to 1000X magnification  Inexpensive, rapid gathering of information  May change the course of a failure analysis

19. Cross-section Diamond Blade 50X

20. © KTA-Tator, Inc.

21. Cross-section at Edge/Corner

22. Tank lining –cross-section

24. Coating Thickness

25. Fourier Transform Infrared Spectroscopy (the IR)  Produces a fingerprint of an individual paint  Can determine if the paint specified was the one actually applied

26. How an IR Works  A spectrometer passes infrared light through a coating sample  Molecules absorb light at different rates  An IR produces a spectrum  Each coating type has its own spectrum

27. Amine Cured Epoxy Coating

28. Gas Chromatography  Detects the presence of solvents trapped in a coating  Gas Chromatography works on the principle of attraction  Each solvent eludes (comes out) at a different rate

29. Solvent Entrapment  Entrapped solvents can cause serious problems  Solvent entrapment can be detected years after application

30. Pyrolysis / Gas Chromatography / Mass Spectroscopy  Pyrolysis- allows for vaporization of a solid sample  Mass Spectroscopy- allows universal identification of separated components  Review-Gas Chromatography- allows for separation of components within a mixture

31. High Performance Liquid Chromatography (HPLC)  Wide range of testing  Employs a liquid, rather than a gas, to carry a sample through the testing columns  HPLC includes:  Ion chromatography  Gel permeation chromatography

32. Ion Chromatography  Six salts can be identified through a single test 1. Chloride4. Nitrite 2. Phosphate5. Nitrate 3. Sulfate6. Bromide

33. Gel Permeation Chromatography  Looking for problems within a resin system  Allows separation of coating components by molecular weight

34. SEM/EDS  Uses magnification up to 5000X and beyond, if necessary  Examines defects in the coating surface  Compares failing and non-failing areas  Provides Elemental Information

35. SEM – EDS of Zinc Layer - Elemental Analysis of Filler  filler consisted elementally of calcium and silicon…… most likely calcium silicate

36. Differential Scanning Calorimetry  Used to determine if a product has properly cured  Useful for product with high mix ratios

37. © KTA-Tator, Inc.

38. Electrochemical Impedance Spectroscopy  AC (alternating current) electricity to measure electrical resistance (impedance)  Impedance used to assess coating integrity and to follow deterioration

39. - - Excellent

41. Results of Laboratory Techniques  Optical Microscopy Starting point /Observation/ Determine path of investigation  Infrared spectroscopy Resin types/mix ratios  Gas chromatography Solvent identification  Ion chromatography Salt identification  GPC Separation / formulation discrepancy  SEM/EDS High magnification / elemental analysis  AA spectroscopy Toxic Metals/ Environmental issues  DSC Degree of cure  EISBarrier properties / track degradation