acrylic, etc.) used in polysiloxane may be slightly more temperature-resistant, by 250 °C everything organic has evapo- rated or burned. If you need performance at 500 °C, consider straight silicone resin coatings.
inorganic systems such as potassium sili- cate, calcium aluminate, and so on.
with anything that cycles.
A A
perature was an issue, polysiloxane ap- plications received the lowest failure ratings according to this report.
A
Protecting machinery foundation
Q
We have a machinery foundation made from
carbon steel (CS). The foundation is designed to be
normally dry, but it might be in contact with salt water or oil at times. Once the machinery is mounted, it will be physi- cally impossible to repair any corroded areas of this foundation short of disman- tling the machinery, which is quite un- practical after installation. We are looking for more or less permanent protection (30 to 50 years). Some of us are considering stainless steel (SS) explosive cladding. Does anyone have any other suggestions for the clad metal and the method, other than explosion cladding? If we use SS, what grade should we consider? The foundation is not yet constructed.
)T[W \PM JI[M Q[ +; ?M LW I [QOVQÅKIV\ amount of thermal spraying and are very familiar with the process; however, it may
NACE International, Vol. 51, No. 11 November 2012 MATERIALS PERFORMANCE 49
I recommend obtaining a copy of the EPRI Report, "Linings at Power Plants." In all power plant applications where high tem-
I have used polysiloxane coatings on a furnace stack at 800 °F (426 °C) with very good results. Be cautious about using them
I agree. If you are looking for a solution for high temperature and also chemically resistant conditions, you should consider
not be adequate for this particular appli- cation. The limited thickness and porosity of thermal spray metals may be a problem for this job. The machine is made of CS and is located on a ship.
A
I would suggest metalizing with a seal coat of polyurethane (PUR) or polyurea. The PUR seal will protect the metal from the salt
water and oil. If the machine remains indoors and is usually dry, this method should easily qualify for the 30 years of minimum protection. Make certain that the base is pitched downward from the geographic center to all of the edges so that condensation will run off and away from the steel. Be sure that maintenance of the drainage is built into the foundation and base.
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