Question

You are designing an air pressure vessel with a corrosion resistant interior coating. Will the surface energy of the interior wall increase or decrease when pressurized? Use drawings to guide your answer.

I believe the answer is that the surface energy will decrease. However, in the instance we learned in class we were looking at a liquid and particles. Therefore, my logic was that the corrosion resistant material would create a lower affinity for the particles in which case absorption would occur, decreasing the surface energy on the interior wall. However, I'm unsure if that same concept applies here

Answer 1

Corrosion resistant interior coating like "epoxy paints" are used in pressure vessels to reduce the losses due to corrosion and pitting. At low surface energy, the surface available for the contact of air with the interior coating will be low. However, when pressurized the surface energy will increase and increasing the pressure above design limit may hamper the internal lining.

Also your theory, absorption is not desired in a pressure vessel, and that will highly disrupt the intramolecular bonds of the lining material, decreasing its lifetime.

initially surface energy is low

however, increasing the pressure