纳米晶Co-Ni-Fe合金镀层在3.5%NaCl溶液中的腐蚀特性

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。

Corrosion Characteristics of Nanocrystalline Co-Ni-Fe Deposits in 3.5% NaCl Solution

Nanocrystalline Co-Ni-Fe alloys were synthesized by pulsed electrodeposition.The composition,microstructure and surface morphologies were studied by EDS、XRD,TEM and SEM,The effect of Co content and grain sizes on the electrochemical corrosion behaviour of nanocrystalline Co-Ni-Fe deposits in 3.5wt% NaCl solution were investigated using Tafel polarization curves.The results reveal that the grain sizes of the nanocrystalline fcc Co-Ni-Fe alloys descrease with increasing of the content of Co in the coating.The grain sizes of nanocrystalline Co-Ni-Fe alloys increase with increasing of the annealing temperature,showing a strong(111)texture.The corrosion rates of Co-Ni-Fe alloys decrease first and then increase with increasing of the Co content in the coating.The corrosion rates decline gradually with increasing of the annealing temperature.Comparing to the nanocrystalline deposits,the coarse grain deposit exhibits a quite a different corrosion morphologies.