The tower’s future looked bleak, but it was saved when local residents were successful in rallying for its restoration instead. Now, the colorful and newly coated tower welcomes everyone to the coastal Florida city.
The “Spoonbridge and Cherry” is an iconic sculpture in Minneapolis, Minnesota. Recently, concern was expressed over the condition of the cherry and its coatings. The cherry was inspected, removed, and recoated. This article describes the rehabilitation process and the materials used.
Wastewater treatment plant components generally
experience both atmospheric and immersion corrosion. Hydrogen sulfide (H2S), which is usually present, has wide-ranging effects in wastewater systems, most notably causing corrosion and odor problems. The corrosion problems can be mitigated by a combination of strategies including judicious selection and implementation of
emerging corrosion-resistant coatings.
Several factors cause deterioration of critical process
equipment in process plants. The options widely
utilized for restoration include conventional repair
or replacement. Nonmetallic composite materials
can be utilized as an option to restore equipment
integrity. This article discusses the material
degradation aspects in critical streams such as the
cooling water system and hydrocarbon pipelines at a
Saudi Arabian gas plant. Nonmetallic composite
coating materials play a vital role in corrosion
protection and life extension of core components.
Because of increasing costs, owners are demanding
longer coating service life. Ten to 15 years is no
longer satisfactory. Simply adding dry film thickness
will not work since many coatings crack at excessive
thicknesses. Recent coating technology advances
permit the use of solvent-free epoxy and
polyurethane systems having >15-year lives. Newer
combinations of epoxy and polysiloxane resins will
make a 25-year life achievable.
A chlorine scrubber fabricated from fiberglass-reinforced plastic (FRP) was installed in 1977.
Major repairs began in 1981 and continued at
four-year intervals. After exploring several
replacement materials, a FRP/ethylene-chlorotrifluoroethylene dual laminate scrubber was selected. This was installed in 1987 and remained in continuous service until the plant shut down in 2001. Examination shortly after plant closing showed the liner to be in excellent condition.
A thorough pre-job meeting is an essential part of
any project. This article covers the requirements of a
pre-job meeting before starting a coating project. It
presents advice on who should attend, the roles of
the attendees, and references needed.
Epoxy/urethane coating systems are widely used for ships and offshore structures because of their excellent resistance to ultraviolet radiation and protection against corrosion. Recently, some of these coating systems used in Korea experienced premature failure. This work investigated the root cause of the failures using pH tests and Fourier transform infrared spectroscopy.
An ethylene chlorotrifluoro-ethylene (ECTFE)
lining of a process vessel handling alkaline-based
fluids and active chlorine was examined after more
than 23 years of service. The examination and tests
showed that the ECTFE material was undamaged.
Test procedures, data evaluation, and
conclusions are presented.
Organic coatings include latex paints, plastics, asphaltic materials, rubbers, and elastomers. The specific material selected for a coating job must have characteristics that would allow its proper application under all conditions existing during the coating process. Proper identification of the physical or other properties of the film expected from the application must be specified.
A brick flue at a generating station was in need of
rehabilitation because of the spalling and cracking
of the brick. This caused a leakage of acid gases into the annulus. A typical flash coat system was not desired because of its relatively short life. A system of corrosion-resistant materials, which has shown excellent performance and durability, was chosen to make the repairs. The system consists of a combination of organic and ceramic-based lining materials. A case history is presented, with descriptions of the operating environment
and materials selection criteria.
Many years ago, early in
my career, I was reminded
that it’s the
little things that make
a standard paint job a
good paint job. Coatings
are too often
thought of as something that must be
done, but it’s not necessary to spend
much time on surface preparation or application. After all, “paint is paint and
anybody can apply paint.”
Di-octyl sebacic acid (DOS-A) is used as rust
preventive oil on steel sheets. When applied
below the maximum level of 75 mg/m2 per side, it is compatible with epoxy paint and does not require any pretreatment of the steel sheets. The incompatibility of DOS-A above this maximum could be caused by weak H-bonding between the acid and epoxy molecule, leading to blistering. The optimum oil level was determined through experimentation to avoid paint failure. It was also observed that a variance in the sheet surface roughness of ±0.4 µm did not appreciably affect paint failure.
There was a defect of severe micro-flow mark lines in
cathodic electrodeposited (CED) primer coating on car
components. This problem was highlighted after final painting. This article describes the tests performed to determine the root cause of the defect. Tests included a surface profile of the CED coating and the determination of the microstructure and nickel
content of the phosphate coating beneath the CED coating. The investigation identified the optimum concentration of nickel in the coating to refine phosphate grain size and create a unity
crystal aspect ratio. It also found that the triple point junction of phosphate crystals determines the porosity to provide a uniform CED coating surface finish.
Applying an organic or metallic barrier coating between a corrosive environment and the material to be protected is a fundamental method of corrosion control. In fact, coatings and linings represent the most widely used method of protecting most metals.