plating, anodizing, & finishing Q&As since 1989
How will Sulfamic Acid affect Stainless Steel, Ductile Iron and Carbon Graphite?
December 12, 2011
Q. We have been asked to design a rotary union that will have Sulfamic Acid pass through it for 1 day. Our customer is attempting to clean the inside of a large roll. The current material of our rotary union are Stainless steel and ductile iron. The seals are made of Carbon Graphite or silicon carbide. Based on this information do you think these materials would hold up for 1 day?
- Three Rivers, Michigan, USA
December 14, 2011
In short, run everything is compatible; however, there will probably be some galvanic current that may allow the sulfamic acid to dissolve some iron and nickel. Also, sulfamic acid in water solution has a pH so low that it begins breaking down into sulfuric acid and ammonia - galvanic problem still there.
Robert H Probert
Robert H Probert Technical Services
Garner, North Carolina