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摩托车发动机的铝合金压铸件汽缸内壁镀铬,主要为提高其耐烧蚀和耐磨性,延长使用寿命.由于铝属两性金属,在酸碱溶液中都不稳定,且表面的氧化膜不易除去,给镀铬带来困难,造成成品率低下.特别是铸铝件(汽缸)有砂眼、气孔等缺陷,往往会降低镀层与铝基的结合力,而且生产中易产生铝基体过腐蚀,严重的甚至造成报废.实践证明,采取相应预防措施,能够将铸铝汽缸镀铬成品率大大提高.现根据本厂实践作如下简介.
Motorcycle engine aluminum alloy die-casting cylinder wall chrome, mainly to improve its resistance to ablation and wear resistance, to extend the service life.As aluminum is an amphoteric metal, are not stable in acid solution, and the surface of the oxide film is not easy to remove , Resulting in difficulties in chrome plating, resulting in low yield .Especially cast aluminum parts (cylinder) with trachoma, porosity and other defects, tend to reduce the coating and aluminum-based combination, and the production of aluminum matrix prone to over-corrosion, serious Even resulting in scrapped.Practice has proved that taking appropriate precautions, to be able to chrome-plated aluminum cylinder greatly improve the yield is now based on factory practice for the following introduction.