greg87
Chemical
- Dec 9, 2002
- 33
I’d like to understand why high purity waters apparently cause high corrosion rates of carbon steel at room temperatures. Is the higher corrosion rate really due to their low ion content, & therefore higher dissolution driving force (ie hungry water explanation)? Is the rate for pure water significantly higher than that of “tap” water under equal conditions? Or is more a function of other factors like the presence of carbon dioxide (carbonic acid) or ??? Are the behaviors the same for the two common types of pure water:
“RO water”: produced by Reverse Osmosis, resulting in approx. 0.5 megohm, pH 5.5-6.5, & containing carbon dioxide.
“DI water”: water made by RO followed by deionization beds which remove all ions and “all” CO2 resulting in 18 megohm, pH neutral water.
(is the conflicting information on this subject due to these differences, and are people extrapolating that info to all “pure water”?)
When these waters are exposed to air, and therefore CO2, is the result a stronger acid, because they have no buffering capacity, and therefore they become more corrosive (than tap water)?
Thanks
“RO water”: produced by Reverse Osmosis, resulting in approx. 0.5 megohm, pH 5.5-6.5, & containing carbon dioxide.
“DI water”: water made by RO followed by deionization beds which remove all ions and “all” CO2 resulting in 18 megohm, pH neutral water.
(is the conflicting information on this subject due to these differences, and are people extrapolating that info to all “pure water”?)
When these waters are exposed to air, and therefore CO2, is the result a stronger acid, because they have no buffering capacity, and therefore they become more corrosive (than tap water)?
Thanks
