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12 Cards in this Set
- Front
- Back
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what is a galvanic cell? |
Galvanic cell is a cell in which chemical energy is converted into electrical energy.• It can be considered a chemical reactor in which a spontaneous chemical reaction takes place and the energy change accompanied the reaction appears in the form of electrical energy.• It consists of two electrodes (i.e., anode and cathode) between which there is a potential difference. |
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what is corrosion? |
Corrosion is the deterioration of metallic structures through chemical and/or electrochemical reactions between the metal and the surrounding environment. |
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what can corrosion be classified into? |
•Chemical (direct) corrosion. •Electrochemical (indirect) corrosion. |
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what is chemical corrosion? |
Chemical corrosion occurs through a direct chemical reaction between metallic object and environment.For instance; dissolution of zinc metal in HCl solution. |
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what is electrochemical corrosion? |
Electrochemical corrosion occurs by forming a galvanic cell between metallic object and environment. This galvanic cell has the following formula: anode/electrolyte/cathode |
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what can corrosion be further classified to? |
corrosion reduction by: oxygen: 1/2 O2 + H2O + 2e- --------> 2OH- hydrogen: 2H+ + 2e- -----> H2 |
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what are mechanisms of electrochemical corrosion? |
mechanisms of electrochemical corrosion include:▪Dissimilar metal corrosion. ▪Differential aeration corrosion. |
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how electochemical corrosion? |
Back (Definition) |
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differential aeration |
Back (Definition) |
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atmospheric form of corrosion |
chemical corrosion electrochemical corrosion |
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chemical corrosion |
o Resulting from dissolution of acidic gases (i.e., SO2, H2S, N O , CO ) in condensed water film or dew droplet on metallic surfaces. |
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electrochemical atmospheric corrosion |
Electrochemical corrosion (formation of galvanic cell)o Fe / electrolyte / Fe3C o Fe / electrolyte / O2 |
