Coatings are applied to more product and material surfaces than you’d ever realize, from the obvious coatings like paint, plaster, or lacquer, to transparent and microscopic coatings you could never see with the naked eye.
Whenever and wherever a coating is applied, it has an important job to do. If a coating fails to perform its intended function, the results could be disastrous. That’s why, whenever coatings fail whoever is responsible for them needs to find out why immediately and prevent it from happening again. Coating failure analysis is what allows them to do that.
What is coating failure analysis?
Coating failure analysis is the scientific process of determining why a coating compound failed to perform its function as expected. It involves a detailed analysis of the failed coating’s materials to determine how and why the failure happened with the ultimate goal of figuring out how to keep it from happening again.
Why is coating failure analysis important?
Simply put, coating failure analysis is important because coatings are important. Businesses apply coatings like paints, lacquers, primers, sealers, and varnishes to their products and equipment to protect them from wear and preserve them for safe use over time.
Should a coating used for this purpose fail, it could have expensive and potentially dangerous consequences for everyone who comes into contact with the coated material. If a plumbing pipe coating fails, for example, then the pipe’s metal could corrode prematurely, leading to a potential burst pipe that could cause water damage.
What kind of failures can coating failure analysis identify?
The many different techniques used in coating failure analysis can identify a huge variety of reasons why a coating might fail. Some of the most common coatings include:
- Paint failures
- Anodization
- Electrodeposition
- Zinc
- Sputtering
How does coating failure analysis work?
There are hundreds of thousands of coatings applied in industrial and manufacturing settings every day. These coatings are comprised of complex combinations of materials and designed specifically for use on the products they protect in the environment in which they must protect them. Any number of these materials or material conditions could trigger coating failure, which makes coating failure analysis a complex and scientific process.
Any coating failure analysis process must accomplish several goals. First, it must identify exactly how the coating failed to perform according to expectations. Then it has to determine exactly why that failure occurred. Failures can occur for a great number of reasons including improper use of materials in creating the coating, improper mixing of materials, misapplication of coating, contaminated substrates, incompatibilities of coatings, or a factor of the environment in which the coating was applied.
The professionals conducting the coating failure analysis should present their recommendations on how to prevent such a coating failure from occurring in the future.
Depending on the kind of coating they have to analyze, the professionals at Innovatech may use any of the following techniques in their coating failure analysis:
Fourier Transform Infrared Spectroscopy (FTIR)
FTIR measures how a sample of the coating in question absorbs several wavelengths of infrared light to determine what the coating compound is made of to an extremely accurate and minute degree.
FTIR is commonly the “first step” of coating analysis because it can tell experts exactly what a coating consists of, allowing them to either find the problematic material or rule out constructing materials as a cause of failure. FTIR is also used to find and identify any contaminants that may have worked their way into the coating during the manufacturing process or after the coating was applied. Additionally, FTIR can be used to evaluate contaminants on the surface of the substrate which can affect adhesion of the coatings.
Scanning Electron Microscopy (SEM)
SEM is a high-resolution surface imaging technique. It bombards a coating sample with electrons to capture imaging of its surface at magnification levels of up to 100,000 times. Different elements on the surface of the coating emit different amounts of electrons in response to bombardment, which creates a high-resolution electron micrograph that experts can see to see materials or contaminants that may be responsible for coating failure.
As a surface imaging technique, SEM is primarily used in coating failure analysis to identify and characterize signs of failure on the surface of the coating that may be too small to evaluate otherwise. By constructing such an accurate picture of the surface of the coating in question, analysts can obtain a great deal of information about the type and cause of failure. SEM analysis can be used to identify the location where the coating has failure and which layer is exhibiting the failure on multilayer coating systems. In addition, the surface topography and microstructure can affect coating performance and these features can be evaluated by SEM analysis.
Depending on the type of failure analysis required, analysts may also apply a form of chemical analysis called Energy Dispersive Spectroscopy, or EDS. EDS measures the energy of the X-rays the sample produces in response to the electron beam interacting with the sample. This can help analysts identify and measure constituent elements beneath the surface of the coating. EDS may be used if SEM imaging does not help analysts identify the source of failure on its own.
Electron Spectroscopy for Chemical Analysis (ESCA)
ESCA, also known as X-Ray Photoelectron Spectroscopy (XPS) is another form of surface analysis. It passes an X-ray beam over the surface of the coating to “excite” the atoms on its surface. When the core electrons within these atoms absorb enough energy, they emit onto the surface of the coating, where they are detected and measured by ESCA equipment.
Measuring these emissions allows ESCA analysis to identify the elements the core electrons emitted from, allowing analysts to determine the elemental makeup of the sample in full. Since the specific amount of binding energy required for electron emission changes based on the chemical environment of the coating, ESCA can also determine the chemical environment each element exists in on the coating. ESCA measures the chemistry of the substrate or coating directly on the surface (<10 nm), compared to SEM/EDS which can penetrate several micrometers into the coating and/or substrate. This makes ESCA best suited to measure pre-treatment layers that are often very thin and also identify the chemical constituents that may contaminate the coating surfaces.
How can I get coating failure analysis?
If you need professional coating failure analysis, the experienced experts at Innovatech are ready to help identify and perform whichever analysis techniques will work best for your coating problem. Get in touch for a quote and more information today.
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