Corrosion & Degradation Workbench

Interactive workspace initializes in your browser. Engineering method, assumptions, validation, and references are available below.

Engineering reference

Corrosion & Degradation: theory, method, and sources

This materials science workspace publishes 10 governing equations, 5 stated assumptions, 1 documented boundary, and 2 sources so the numbers it returns can be checked rather than taken on trust.

Calculations run locallyCalculation & source methodology

How this tool works

Ten modules cover Faraday mass loss, penetration rate, galvanic driving force, the Nernst equation, Tafel kinetics, parabolic oxidation, coating life, Arrhenius test acceleration, Miner’s cumulative damage, and stress corrosion cracking margin.

Electrochemical rate, physical penetration, and remaining service life are linked, so a measured corrosion current density can be carried through to a thickness loss and a coating replacement interval.

Calculators and topics covered

corrosion
oxidation
aging
coatings
fatigue damage
Faraday law
Nernst equation
Tafel
Miner rule
stress corrosion

Core equations

\text{Faraday’s law:}\quad m = \frac{ItM}{nF}

\text{penetration rate:}\quad CR = \frac{3.27 \times 10^{-3} \cdot i_{\mathrm{corr}} \cdot EW}{\rho }\; \left(\frac{\mathrm{mm}}{yr}\right)

\text{galvanic driving force:}\quad \Delta E = E_{\mathrm{cathode}} - E_{\mathrm{anode}}

\text{Nernst equation:}\quad E = E {}^{\circ} - \left(\frac{RT}{nF}\right) \ln \; Q

\text{Tafel kinetics:}\quad i = i_{\mathrm{corr}} \cdot 10^{\frac{\eta }{\beta }}

\text{parabolic oxidation:}\quad x^{2} = k_{p} \cdot t

\text{coating life:}\quad t = \frac{\text{thickness}}{\text{loss}\; \text{rate}} \times \text{utilization}

\text{Arrhenius acceleration factor:}\quad AF = \exp \left[\left(\frac{Q}{k}\right) \left(\frac{1}{T_{\mathrm{use}}} \frac{- 1}{T_{\mathrm{test}}}\right)\right]

\text{Miner’s rule:}\quad D = \sum \left(\frac{n_{i}}{N_{i}}\right),\; \text{failure}\; at\; D = 1

stress corrosion margin: K_applied vs K_ISCC threshold

Method and assumptions

Assumptions

Uniform corrosion is assumed; pitting, crevice, and intergranular attack are localized and not captured by an average rate.
Corrosion current density is taken as constant over time, whereas real rates change as films and products build up.
Parabolic oxidation applies only to diffusion-controlled protective scale growth, not to breakaway or spalling oxidation.
Arrhenius acceleration assumes the same degradation mechanism operates at both test and service temperature.
Miner’s rule assumes linear damage accumulation and ignores load sequence effects.

Limitations and design boundaries

Educational screening models only. Material certification, process qualification, applicable standards, statistical variability, environmental conditioning, and professional engineering judgment are required for real selection or design.

Sources and references

Primary sources are preferred for ratings, standards, manufacturer data, and externally defined constants.

Source policy

Callister and Rethwisch, Materials Science and Engineering: An Introduction
Askeland and Wright, The Science and Engineering of Materials