DIAGRAMAS DE POURBAIX PDF

Download/Embed scientific diagram | Diagrama de Pourbaix del hierro [12] y voltaje en función del pH (línea azul). from publication: Síntesis de nanopartículas. Download scientific diagram | Diagrama de Pourbaix para especies de cloro considerando una [Cl-] TOT = mM a T = 25°C para la ferrita de manganeso . ESPECIE. ΔG° (cal/mol). Pb. 0. PbO. , Pb3O4. , Pb2O3. , PbO2. , Pb2+. -5, Pb4+. 72, H2O. , REACCIONES DE.

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Geological Survey water-Supply Paper The vertical axis is labeled E H for the voltage potential with respect to the standard hydrogen diagramsa SHE as calculated by the Nernst equation.

See diagrams at right. Passivation occurs when the metal forms a stable coating of an oxide or other salt digaramas its surface, the best example being the relative stability of aluminium because of the alumina layer formed on its surface when exposed to air.

Views Read Edit View history. Predominant ion boundaries are represented by lines. The reaction equation is:. For the simple case of a thermodynamic system consisting of a metal M and water, various reaction equations may be written having the form:.

fe In these cases, pE is used instead of E H. The lines in the Pourbaix diagram show the equilibrium conditions, that is, where the activities are equal, for the species on each side of that line. Environmental Chemistry – a global perspective 3rd ed. On either side of the line, one form of the species will instead be said to be predominant.

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The reaction equation is found to be:. In other projects Wikimedia Commons.

Usually, the activity of a species is approximated as equal to the concentration for soluble species or partial pressure for gases. Sometimes additional lines are drawn for other concentrations. Similarly to phase diagrams, they do not allow for reaction rate or kinetic effects.

Diagrama de Pourbaix – Wikipédia, a enciclopédia livre

Archived copy as title Commons category link is on Wikidata. The reaction equation may be written:. The equation must be balanced for M, H, O and charge. As such a Pourbaix diagram can be read much like a standard phase diagram with a different set of axes. The same values should be used for all species present in the system. Retrieved from ” https: Pourbaix diagrams have several uses, for example in corrosion studies, geoscience and in environmental studies.

There are three types of line boundaries in a Pourbaix diagram: The “H” stands for hydrogen, although other standards may be used, and they are for room temperature only. In addition, changes in temperature and concentration of solvated ions in solution will shift the equilibrium lines in accordance with the Nernst equation.

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Diagrama de Pourbaix

Archived from the original on From Wikipedia, the free encyclopedia. A simplified Pourbaix diagram indicates regions of “Immunity”, “Corrosion” and “Passivity”, poourbaix of the stable species.

Pourbaix diagrams are also known as E H -pH diagrams due to the labeling of the two axes.

A base-balanced equation can be converted to an acid-balanced equation using the equilibrium constant for the self-ionization of waterand only acid-balanced equations are considered below.

The diagrams also do not take kinetic effects into account, meaning that species shown as unstable might not react to any significant degree in practice. This will vary with temperature. In many cases, the possible conditions in a system are limited by the stability region of water.