What Is the Mixed Potential Theory Corrosion Calculator?
Mixed potential theory states that electrochemical reactions occurring on a conductive surface couple to reach a common mixed potential Ecorr.
No net charge accumulates on the metal, requiring the total rate of oxidation to equal the total rate of reduction.
How Does the Mixed Potential Theory Corrosion Calculator Work?
The intersection of anodic and cathodic polarization curves determines Ecorr and icorr.
The Stern-Geary constant B connects icorr to linear polarization resistance Rp measured via LPR probes.
Mixed Potential Theory Corrosion Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Evans diagram intersection equations based on Tafel activation polarization kinetics.
How to Use the Mixed Potential Theory Corrosion Calculator
- Enter reversible potentials, exchange current densities, and Tafel constants for both half-cell reactions.
- Obtain corrosion potential, current density, and polarization resistance.
Step-by-Step Example Calculation
Carbon Steel Acid Corrosion
Input Values:
Understanding Your Result
icorr directly translates to material loss rate in mm/year via Faraday’s Law.
A high polarization resistance Rp corresponds to low corrosion rates.
Factors That Affect the Result
- Oxidizer concentration (dissolved O2) shifts cathodic exchange current and increases corrosion rate.
- Passivation reduces anodic dissolution kinetics by orders of magnitude.
When Should You Use This Calculator?
- Corrosion engineering, LPR sensor data interpretation, inhibitor screening, and galvanic coupling studies.
Assumptions & Limitations
- Assumes activation-controlled Tafel polarization without mass transfer / diffusion limiting current.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Rigorous analytical solution of coupled Butler-Volmer Tafel lines.