4.接触腐蚀 如果铝及其合金与异种金属材料长久接触.往往会产生接触腐蚀。 1)与异种金属材料长久接触会产生电蚀(电池作用腐蚀)。 2)与非金属材料接触会产生接触腐蚀(间隙腐蚀)。 一般金属材料及其合金单独在电解溶液中都能保持各自的电极电位,但是与高电位的银(-0.08V)、铜(-0.20V)、铁(-0.58V)相比,低电位的铝(-0.85V)、锌(-1.00V)、镁 4. Contact corrosion If aluminum and its alloys and long-term contact with dissimilar metal materials, tend to produce contact corrosion. 1) long-term contact with dissimilar metal materials will produce galvanic corrosion (the role of battery corrosion). 2) contact with non-metallic materials will produce contact corrosion (gap corrosion). Generally, the metal materials and their alloys can maintain their own electrode potentials in the electrolytic solution alone. However, compared with the high potential of silver (-0.08V), copper (-0.20V) and iron (-0.58V), the low potential Aluminum (-0.85V), Zinc (-1.00V), Magnesium