FAC often affects carbon steel piping carrying ultra-pure, deoxygenated water or wet steam.
FAC of carbon steel halts in the presence of small amount of oxygen dissolved in water.
FAC does not involve impingement of particles, bubbles, or cavitation which cause the mechanical (often crater-like) wear on the surface.
By contrast to mechanical erosion, FAC involves dissolution of normally poorly soluble oxide by combined electrochemical, water chemistry and mass-transfer phenomena.
Nevertheless, the terms FAC and erosion are sometimes used interchangeably because the actual mechanism may, in some cases, be unclear.