Corrosion Doctors site map Corrosion information hub: The Corrosion Doctor's Web site Corrosion engineering consultant

 

Welcome

Site index

A to Z listing

Advertising  

Books

Corrosion glossary

Disclaimer

Famous scientists

Corrosion course

Distance Ed

Doomsday scenarios

Links

Modules

Monitoring glossary

Photo gallery

Rare earths

Search this site

Textbook assignments

Toxic elements

Water glossary

Webmaster

 


Corrosion Rate Conversion

The following charts provide a simple way to convert data between the most common corrosion units in usage, i.e. corrosion current (mA cm-2) , mass loss (g m-2 day-1) and penetration rates (mm y-1 or mpy) for all metals or for steel

mA cm-2

mm year-1

mpy

g m-2 day-1

mA cm-2

1

3.28 M/nd

129 M/nd

8.95 M/n

mm year-1

0.306 nd/M

1

39.4

2.74 d

mpy

0.00777 nd/M

0.0254

1

0.0694 d

g m-2 day-1

0.112 n/M

0.365 /d

14.4 /d

1

  • where:

    • mpy = milli-inch per year

    • n = number of electrons freed by the corrosion reaction

    • M = atomic mass

    • d = density

Note: you should read the Table from left to right, i.e.:

1 mA cm-2 = (3.28 M/nd) mm y-1 = (129 M/nd) mpy = (8.95 M/n) g m-2 day-1

For example, if the metal is steel or iron (Fe), n =2, M = 55.85 g and d = 7.88 g cm-3 and the Table of conversion becomes:

mA cm-2

mm year-1

mpy

g m-2 day-1

mA cm-2

1

11.6

456

249

mm year-1

0.0863

1

39.4

21.6

mpy

0.00219

0.0254

1

0.547

g m-2 day-1

0.00401

0.0463

1.83

1

Note: you should read the Table from left to right, i.e.:

1 mA cm-2 = 11.6 mm y-1 = 456 mpy = 249 g m-2 day-1