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13 Cards in this Set
- Front
- Back
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Define Corrosion: |
Corrosion is the electrochemical deterioration of a metal because of its chemical reaction with the surrounding environment. The reaction occurs due to the tendency of metals to return to their natural state. |
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A metal which had the tendency to corrode. |
Anode. |
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A dissimilar conductive material which has less tendency to corrode than the anode must be present. |
Cathode |
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A conductive liquid that connects the anode to the cathode. |
Electrolyte |
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State Corrosion type: Occurs when different metals are in contact with each other and an electrolyte, such as salt water. Recognizable by the presence of build up of corrosion at the joint between the metals. |
Galvanic Corrosion |
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State Corrosion type: Or etching results from a direct chemical attack on a metal surface and involves only a metal surface. Seen as dulling or etching, if allowed to continue can look like frost. |
Uniform Surface Corrosion |
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State Corrosion type: Advanced form of inter-granular corrosion where the surface grains of metal are lifted up by the force of expanding corrosion products occurring at the grain boundaries. Occurs on aluminum and magnesium parts |
Exfoliation Corrosion |
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State Corrosion type: Occurs when the electrolyte has a different concentration from one area to another. Electrolyte inside crevice contains less oxygen and more metal ions than the electrolyte just outside the crevice. |
Crevice/Concentration Cell Corrosion |
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State Corrosion type: The most common corrosion on aluminum and magnesium alloys. First noticeable as a white or gray powdery deposit, similar to dust, which blotches at the surface. When deposit is cleaned away, tiny pit holes can be seen on the surface. |
Pitting Corrosion |
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State Corrosion type: This corrosion attacks the grain boundaries of the metal. |
Intergranular Corrosion |
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State Corrosion type: Special form of crevice or oxygen concentration corrosion on metal surfaces having an ORGANIC coasting system. Recognized by its worm like trace of corrosion products beneath the surface. |
Filmiform Corrosion. |
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State Corrosion type: Occurs in combination of surface wear. Corrosion products increase the wear of the surface and the wear exposed more bare metal. Generally has the appearance of galling. |
Fretting Corrosion |
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State Corrosion type: "Hot Corrosion" Corrosion in the absence of water occurs at high temperatures by the chemical reactions released from the gases produced. |
High Temperature Oxidation |
