扫描电镜观察用的铸铁深腐蚀试样,通常是将样品浸泡在浓度为10～20％的盐酸酒精溶液中制备的。在此过程中,铸铁的各相,由于电极电位的差异,铁素体和渗碳体依次被腐蚀掉,而石墨则因不受酸的腐蚀而保留着。因此,在基体腐蚀达一定深度后,石墨便被单独暴露出来了。但是,这种化学深腐蚀方法存在以下问题:一是腐蚀时间长,一般需几十个小时;二是对试样制备技术的要求十分严格,经深腐蚀后的试 Deep-etched samples of cast iron for scanning electron microscopy are usually prepared by immersing the sample in a hydrochloric acid solution with a concentration of 10 to 20%. During this process, ferrite and cementite are corroded in turn due to differences in electrode potential, while graphite is retained due to acid corrosion. Therefore, the corrosion of the substrate reaches a certain depth, the graphite will be exposed alone. However, this method of deep chemical etching has the following problems: First, the corrosion time is long and generally takes dozens of hours. Second, the requirements of the sample preparation technology are very strict. After the deep-eroded test