时间：2011-03-11 23:13来源：蓝天飞行翻译 作者：admin 点击：次
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gallon, Imperial. A unit of liquid measurement used in the United Kingdom. One Imperial gallon is the volume occupied by ten pounds of pure water under specified conditions of temperature and pressure. One imperial gallon is equal to 277.4 cubic inches, 4.55 liters, or 1.201 U.S. gallons. gallon, U.S. A unit of liquid measurement used in the United States of America. One U.S. gallon is equal to 231 cubic inches, 128 fluid ounces, 3.785 liters, or 0.832 imperial gallon. galvanic action. Electrical pressure within a substance which causes electron flow because of the difference of electrode potential within a material. galvanic corrosion. A form of corrosion that occurs between two metals having different locations in the electrolytic, or galvanic, series. See galvanic series. Corrosion can take place any time two metals are covered with an electrolyte. The amount of corrosion is determined by the difference in the location of the two metals in the galvanic series. The more active metal (the metal highest in the galvanic series) acts as the anode in the electrolytic process, and is eaten away. The more noble metal is not affected. galvanic couple. A pair of unlike metals that produce an electrical potential when they are covered with an electrolyte. Copper and zinc form a commonly used galvanic couple. When a piece of copper and a piece of zinc are covered with the same electrolyte, a voltage is produced between them. The zinc, being the less noble of the two metals, forms the anode. Electrons leave the zinc and travel to the copper. The copper is the positive terminal of the galvanic couple, and the zinc is the negative terminal. galvanic generation of electricity. The production of electricity by chemical action. Electricity produced by dry-cell batteries and storage batteries are examples of galvanic production of electricity. galvanic grouping. The arrangement of metals in a series according to their electrode potential difference. galvanic series. A list of metals arranged in the order of their chemical activity. The metals are listed in their order of activity with the more active (least noble) metal being the anode in an electrolytic action. galvanizing. A form of corrosion protection for steel parts in which the surface of the steel is covered with a coating of zinc. The zinc may be applied by hot dipping or by electroplating. |
