为了预防和消除管线钢在柴油中的腐蚀,采用宏观观察、扫描电镜(SEM)、能谱仪等对浸入不同水含量的0号柴油中的X60管线钢的腐蚀行为进行研究。结果表明:0号柴油可以在X60管线钢表面形成油膜,可增加管线钢的抗腐蚀能力,但水的存在将弱化油膜对X60管线钢的保护;当0号柴油中添加0.5 m L/L水,X60管线钢表面出现点蚀,点蚀数量和大小随着含水量增加而增加,也随浸泡时间延长而增加,水参与并控制X60钢的电化学腐蚀,腐蚀产物为黑色的氧化亚铁。
The influences of two kinds of casting modules of metal casting （MC） and expandable pattern casting （EPC） on the corrosion behavior of Mg-11Gd-3Y alloy were studied by electrochemical measurements, scanning electron microscopy （SEM） observation, X-ray diffractometry （XRD） and X-ray photoelectron spectroscopy （XPS） analysis. It is found that the quantity of the Mg 24 （Gd, Y） 5 phase in MC is more than that in EPC due to the cooling rate. There is more alloying element dissolved in the matrix compared with MC. For EPC, the galvanic corrosion effect between the matrix and the Mg 24 （Gd, Y） 5 phase decreases and the corrosion resistance increases compared with the MC. The chief corrosion mode for Mg-11Gd-3Y alloy is pitting corrosion because most of the alloying elements are transformed into intermetallic phases. The average corrosion rate of the MC alloy in the immersion test is five times higher than that of EPC alloy and yttrium is present in the product film, which will provide increased protection for Mg-11Gd-3Y alloy. The electrochemical measurements and immersion test show that the EPC process increases the corrosion resistance compared with the MC Mg-11Gd-3Y alloy.
