Adhesion Strength of Protective Coatings – Test Method Development under Real-Life Hydraulic Conditions
Can a new test method be developed that provides reliable results for adhesion strength of coating systems in high flow applications? Can this method be applied generally to a wide variety of infrastructure and equipment (i.e. penstocks, trash racks, pipe lines, gates and valves, and naval equipment such as ship hulls and rudders)?
Need and Benefit
Coatings issues were identified as the top priority in a recent Research Roadmap for Mechanical Components of
Hydropower Plants (draft, final expected 2018). The specific research need states "Improve durability & extend service
life for coatings materials in high velocity environments" which is directly supported by this proposed study.
In addition, Flatiron Powerplant penstocks and Enders Dam outlet pipe have had recent issues with coating adhesion
and durability. We were also contacted by NRL in early 2017 to help address their needs in improving test methods
that simulate real life operating conditions for coatings within the Navy. Extending the service life of coatings in
penstocks and outlet pipes is an urgent Reclamation need since many coal tar enamel linings are approaching the
end of their service life. Improving test methods that provide more robust, real life results of coating performance will
greatly benefit every region in Reclamation as well as other government agencies.
Most penstock and outlet pipe relining jobs cost $2-10 million dollars due to the amount of surface area, diameter and
length, confined space, extra safety precautions, and complexity of working on steep slope. For the past 20 years
Reclamations coatings have been highly recommended by coating manufacturers' suggestions. Unfortunately, at
Flatiron powerplant for example, the coating only lasted 4 years before delamination occurred. In 2017, a second
contract to repair the damage was set for $500,000. There are hundreds of penstocks and outlet pipes in
Reclamations inventory and this study's objective is to develop a laboratory screening test that subjects coatings to
similar dynamic flow conditions seen in penstocks and outlet pipes.
Contact the Principal Investigator for information about partners.
Bureau of Reclamation Review
The following documents were reviewed by experts in fields relating to this project's study and findings. The results were determined to be achieved using valid means.
Test Method Development for Adhesion Strength of Protective Coatings under Real-Life Hydraulic Conditions (final, PDF, 2.3MB)
By Josh Mortensen, Jacob Carter-Gibb
Report completed on September 30, 2020