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利用脉冲电沉积技术制备纳米晶Co-Ni-Fe合金镀层。用EDS、XRD、TEM和SEM等手段分析纳米晶镀层的成分、微观组织结构和表面形貌。用电化学极化方法研究镀层中Co含量和退火温度对纳米晶Co-Ni-Fe合金镀层在3.5%(质量分数,下同)NaCl溶液中腐蚀行为的影响。结果表明,纳米晶Co-Ni-Fe合金镀层的晶体结构为单一面心立方结构,其晶粒尺寸随镀层Co含量的增加而减小。镀层的晶粒尺寸随退火温度的升高而增大,并呈现强的(111)织构。纳米晶镀层的腐蚀速率随Co含量的增加先下降而后上升。退火可明显降低纳米晶镀层的腐蚀速率。纳米晶与粗晶Co-Ni-Fe合金镀层经电化学腐蚀后呈现出完全不同的腐蚀形貌。
Preparation of Nanocrystalline Co-Ni-Fe Alloy Coating by Pulse Electrodeposition. The composition, microstructure and surface morphology of nanocrystalline coatings were analyzed by EDS, XRD, TEM and SEM. The influence of Co content and annealing temperature on the corrosion behavior of nanocrystalline Co-Ni-Fe alloy coating in 3.5% NaCl solution was studied by electrochemical polarization method. The results show that the crystal structure of nanocrystalline Co-Ni-Fe alloy coating is a single face-centered cubic structure, and its grain size decreases with the increase of Co content. The grain size of the coating increases with the annealing temperature and exhibits a strong (111) texture. The corrosion rate of nanocrystalline coatings decreases first and then increases with the increase of Co content. Annealing can significantly reduce the nanocrystalline coating corrosion rate. The nanocrystalline and coarse-grained Co-Ni-Fe alloy coatings show completely different corrosion morphologies after electrochemical corrosion.