高强度航空铝合金结构材料2024-T3在3.0%(质量分数)Na2SO4溶液中发生局部腐蚀的过程中， 电位噪声的谱功率密度(SPD)曲线都具有相同的特征， 即在极低频下为白噪声， 随着频率的升高逐渐转化为1/Fα噪声。 相应于一个噪声信号波， 有一个腐蚀孔出现。 在孔蚀诱导期， 白噪声水平升高，截止频率增大， SPD曲线的倾斜段直线斜率小于-20dBV/decade， 且趋于增大。 孔蚀发生后， 上述3个参量则各自朝着上述方向的逆方向变化。 孔蚀时的Hurst指数(H)小于非孔蚀期的Hurst指数， 而孔蚀时的系统分维(D)则大于非孔蚀期的系统分维。
The features of electrochemical noise (EN) of high-strength 2024-T3 aluminum alloy in 3.0%(mass fraction)Na2SO4 solution during pitting corrosion have been investigated. The results show that all the EN observed are low frequency noises and the white noise (PW) which is independent of frequency in the superlow frequency domain and changes to the 1/fα noise with the increasing of frequency. Each pit on the surface of corroding electrode corresponds to a sudden jump of electrode potential in time domain. During induced duration of pitting corrosion， the level of white noise and the value of cut-off frequency (fC) increase with the immersion time， while the absolute value of slope of SPD curve's linear part decreases. On the other hand， the above three parameters change in the opposite direction after a pit or a series pits are formed. When a pit is generating the Hurst index is much smaller than that of before or after a pit is formed. Therefore， it is possible to infer the useful information of a corroding electrode according to the value of Hurst index.
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