Fe基非晶及纳米晶合金的制备和电化学腐蚀行为

Preparation and Electrochemical Corrosion Behavior of Amorphous and Nanocrystalline Fe-Based Alloys

摘要:

分别采用单辊甩带法和非晶晶化退火法制备出非晶及纳米晶合金Fe73.5Si13.5B9Nb3Cu1；利用DSC、XRD和TEM对该非晶合金的晶化行为进行了分析；并用电化学极化曲线的方法和电化学阻抗技术研究了该非晶合金经不同温度退火后在1 mol/L HCl溶液里的电化学腐蚀行为。结果表明，该非晶合金的晶化过程出现2个阶段。当退火温度为500 ℃时，合金尚未晶化，仍保持非晶态；当温度达到550 ℃时，出现了晶化衍射峰，晶粒平均直径约13 nm；当温度达到600 ℃时，晶粒平均直径约为15 nm。经过退火得到的纳米晶合金的腐蚀电位大于未退火的非晶，且阳极电流密度变得更低，表明纳米晶状态时的耐腐蚀性能比非晶状态的更好。该非晶合金未退火、550 ℃退火和600 ℃退火时的EIS均由单一容抗弧构成，具有一时间常数；且随着退火温度升高，电化学反应电荷转移电阻在增大

Abstract:

Amorphous Fe73.5Si13.5B9Nb3Cu1 alloy was prepared by the chill block melt-spinning process and the nanocrystalline alloy was obtained by amorphous crystallization annealing. The crystallization behavior was analysed by DSC, XRD and TEM. The electrochemical corrosion behavior in different annealed states was investigated by linear polarization method and electrochemical impedance spectroscopy in 1 mol/L HCl solution. The results show that the crystallization of the amorphous alloy occurs in the two steps. Some nanometer crystals appear when annealed at 550 oC and 600 oC with grain size of 13 nm and 15 nm, respectively. The nanocrystalline alloy has higher corrosion potential and lower anodic current density than amorphous alloy. It indicates that nanocrystalline alloy has a higher corrosion resistance. Amorphous and nanocrystalline Fe73.5Si13.5B9Nb3Cu1 alloys both consist of only single semi-circle. The charge transfer reaction resistances increases as the annealing temperature rises.