Coating Failure Investigation
RAE Engineering and Inspection Ltd. provides laboratory and consulting services to determine the cause of coating failures and to identify remedies to avoid future failures.
Coating Failure
All coatings deteriorate in the course of service, where the rate of deterioration depends upon the coating being used, exposure conditions, and performance requirements. Coating failure occurs when a protective coating does not live up to it's expected service life and performance. Identification of the cause of the failure is made more complex by the large number of coatings and coating types available, a wide range of coating application requirements, and a large variety of service conditions and performance requirements.
The consequences of coating failure include:
- Corrosion of the substrate leading to equipment failure, environmental spills, and/or injury to operating personnel.
- Costly rework and downtime.
- Contamination of cargo.
- Aesthetic failure.
- Possible litigation.
Microscopy, showing multcoat system details
Why do failure investigation:
- Avoid similar, costly failures in the future.
- Determine if similar failures are likely to occur elsewhere in your equipment or facilities.
- Specify better, or more suitable coatings for equipment and facilities to be coated in the future.
- Identify the cause of the failure, for purpose of litigation and legal liability.
Services by RAE Engineering and Inspection Ltd. in failure investigation include any or all of the following:
- Site visits by RAE Engineering and Inspection Ltd. to view the failure.
- Interviews of various parties for background information.
- A review of the construction and painting history.
- Collection of samples for laboratory analysis.
- Laboratory analysis which includes detailed visual, chemical, and physical analyses to determine the cause of coating failure.
- Identification of the cause of the failure confirmation of the cause by re-creating it in the laboratory, if applicable recommendations of remedial action.
Coating failures are typically related to one or more of the following factors:
- Surface preparation.
- Incorrect coating selection.
- Poor specification.
- Deficiencies in coating mixing or application.
- Formulation errors.
- Poor equipment design.
RAE Engineering and Inspection Ltd. makes quantitative measurements of film thickness, number of coats, film thickness per coat, adhesion, and surface profile, as required. Blister fluid can be sampled and analyzed. Surface contamination can be observed and identified.
RAE Engineering and Inspection Ltd. also uses a variety of laboratory techniques to identify the cause of the failure. These techniques include:
- Optical microscopy,
- FTIR (Fourier Transform Infra-Red) spectroscopy,
- SEM/EDX (Scanning Electron Microscopy with X-ray analysis) for detailed examination of coating structure and elemental composition,
- XRD (X-Ray Diffraction) for pigment identification, and gas/liquid chromatography for analysis of (entrapped) solvent.
In many cases, the failure mechanism can be confirmed by re-creating the failure under controlled laboratory conditions.
Coating with wrinkling and resin separation