Water-wall Tube in Power Boiler
Observation : Undercut corrosion, multi-color deposits
(red, white, black). This is a view of a tube ID following
cleaning.
Cause : Acid Phosphate Attack Remarks : Under-deposit corrosion mechanism caused by
reaction of phosphate with magnetite for form maracite. Most
often found in high heat areas of the boiler. Typically
associated with boilers suffering phosphate hideout and
using disodium phosphate or sodium hexametaphosphate.