铈对纳米晶锌镀层耐蚀性能的影响

摘要

By adding cerium salt in the acidic sulfate bath used for direct current electrodeposition of nanocrystalline zinc coating, a new nanocrystalline coating was deposited. The composition, morphology and structure of the coating were characterized by Atomic Emission Spectrometry, X-ray diffraction and scanning electron microscopy. The influence of Ce on corrosion resistance of nanocrystalline zinc coating was investigated by electrochemical methods. The results show that with Ce2(SO4)3 o 8H2O in the bath, a small amount of Ce can be obtained in the coating and give rise to the grain refinement of zinc deposits. Compared with the pure zinc coating, the one containing Ce has the better corrosion resistance. The improvement of corrosion performance is due to the formation of a denser product layer consisting mainly of Zn5(OH)8Cl2 o H2O and its preferred orientation different from that of pure zinc coating.%在酸性硫酸盐直流电沉积纳米晶锌镀层的镀液体系中,引入铈盐后沉积得到新的纳米镀层.运用AES(原子发射光谱)、XRD及SEM等方法表征了含铈纳米晶锌镀层的化学组成与结构,采用电化学方法研究了铈对纳米晶锌镀层耐腐蚀性能的影响.结果表明,镀液中加入硫酸亚铈后,能够沉积得到含有少量铈的纳米晶锌镀层,并且晶粒也发生了轻微的细化；与单纯锌镀层相比,含铈的锌镀层具有更高的耐蚀性能,其原因在于腐蚀过程中形成了更为致密的、以Zn5 (OH)8Cl2·H2O为主的产物层,且Zn5 (OH)8Cl2·H2O的择优取向与纯锌镀层不相同.