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

Corrosion Rate Conversion

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

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

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

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