Equivalent Weight Calculator

Electrochemical corrosion rate measurements often provide results in terms of electrical current. These calculations can be complicated for alloys and metals with elements having multiple valence values.
Equivalent Weight—Equivalent weight, EW, may be thought of as the mass of metal in grams that will be oxidized by the passage of one Faraday (96 489 6 2 C (amp-sec)) of electric charge. (More information can be obtained from the ASTM)

Pure Element: EW = W/n
W = Atomic weight of the element
n = Valence (the number of electrons required to oxidize an atom of the element in the corrosion process)

Alloy: EW = 1 / ∑(nifi/Wi)
fi = The mass fraction of the i^th element in the alloy
Wi = Atomic weight of the i^th element in the alloy
ni = Valence of the i^th element in the alloy

Element

Atomic Weight
(Wi)

Valence
(ni)

Percentage
(fi)

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Atomic Weight 1 (Wi)

Valence 1 (ni)

Percentage 1 (fi)

×

Atomic Weight 2 (Wi)

Valence 2 (ni)

Percentage 2 (fi)

Equivalent Weight:

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Equivalent Weight Calculator