基于MATLAB的304不锈钢点蚀行为电化学噪声特征

Electrochemical Noise Characteristics of 304 Stainless Steel Pitting Based on MATLAB

【目的】研究304不锈钢在质量分数3.5%NaCl溶液中的腐蚀行为。【方法】基于MATLAB软件,利用分段多项式拟合、快速傅里叶变换和希尔伯特黄转换的方法设计电化学噪声信号分析模块,得到噪声信号的时域谱图、功率谱密度图和幅值-频率-时间三维分布图。【结果】时域谱图中有明显的4个阶段,分别对应于不同的点蚀发展过程;在频域分析时,白噪声水平与低频区PSD线性部分斜率的分析结果与时域分析结果具有较好的一致性;HHT时频谱图瞬时频率的分布与点蚀发展过程相对应。【结论】分析系统实现方法简单、数据处理速度快、处理方法灵活,可以实现噪声数据的处理与分析。

【Objective】The corrosion behavior of 304 stainless steel in 3.5%(mass fraction) NaCl solution was studied.【Method】The noise signal of time domain , the power spectrum density and the amplitude-frequency-time 3D spectrums which were obtained by the design of electrochemical noise signal analysis module based on MATLAB used the methods of piecewise polynomial fitting, fast Fourier transform and Hilbert-Huang transform.【Result】The experimental results showed that there were four distinct stages corresponding to different pitting development processes. In the frequency domain analysis in the time domain spectrum;the results of the white noise level and the slope of the linear part of the PSD in the low frequency region were consistent with the results of the time domain analysis. The distribution of instantaneous frequency in HHT spectrum mapped corresponds to the pitting development process.【Conclusion】This analysis system had the advantages of simple implementation, fast data processing speed and flexible processing method, and could realize noise data processing and analysis.