获得一个干净、清晰的断口,在金相失效分析中有着重要的意义。建筑中使用的钢铁零件断裂后,断口上常常附有水泥及混凝土,由于附着牢固、覆盖层较厚,用薄膜粘净、刮凿等物理方法很难去除干净,经试验,用10％～25％铬酸水溶液可以将断口上的水泥、混凝土快速、洁净地清除。该法方便、经济,对断口的腐蚀作用较小,使断口重新显现出断裂时原有的断裂形貌及裂源。 铬酸溶液的配制 在100ml蒸馏水中加入适量铬酐,配成10％～25％的铬酸溶液,室温下使用。溶液中 Obtaining a clean, clear fracture has important implications in the analysis of metallographic failure. After the steel parts used in the construction are broken, the concrete and concrete are often attached to the fracture surface. Due to the firm adhesion and the thick coating, physical methods such as thin film sticking and scraping are difficult to remove. After testing, % Chromic acid solution can fracture the concrete, concrete quickly and cleanly removed. The method is convenient, economical and has less corrosive effect on the fracture, so that the fracture reappears the original fracture morphology and source of fracture. Preparation of chromic acid solution In 100ml of distilled water, add an appropriate amount of chromic anhydride, dubbed chromic acid solution 10% ~ 25%, used at room temperature. Solution