Zinc (Figure 14.1c), and, finally, let us realise that the copperplating was just a convenient reaction to use up the electrons from the zinc and any. Pourbaix diagrams A Pourbaix diagram is a graph of potential against pH and shows on it the. Install vlc eee pc 701 4g software. 2 [ELECTROCHEMISTRY OF CORROSION/BM] Mn+ + ne-' M (2) n+ = n+ + n+ M M /M o r,M /M ln a nF RT E (3) E where R is the gas constant, T the absolute temperature, F the Faraday and n the number of electrons transferred per ion.

Pourbaix diagram of iron Pourbaix Diagram of at 25 oC The following diagram, produced with the KTS Thermo Excel add-on and modified for the Internet, describes the potential- equilibrium diagram for the system iron-water at 25 oC considering only the hydrated forms of the possible s. The gray zone describes the region of stability of the base metal (Fe or iron), also called the immunity region according to Pourbaix. The orange zone indicates where one could expect to see rust, a non-protective form of corroded iron. () Thermodynamic principles can help explain a corrosion situation in terms of the stability of chemical species and reactions associated with corrosion processes. However, thermodynamic calculations cannot be use to predict corrosion rates.

When two are put in contact, they can produce a voltage as in a battery or electrochemical cell causing galvanic corrosion. The material lower in what has been called the will tend to become the anode and corrode while the material higher in the series will tend to support a cathodic reaction. Iron or aluminum, for example, will have a tendency to corrode when connected to graphite or platinum. What the series cannot predict is the rate at which these metals corrode. Have to be used to estimate these rates. See also:,,,.