热机械循环Mg_2B_2O_5/AZ31复合材料电化学腐蚀行为研究

Research on Electrochemical Corrosion Behavior of Thermal Mechanical Cycle Mg_2B_2O_5/AZ31 Composite

对Mg2B2O5/AZ31复合材料在热循环条件下的试样进行了电化学腐蚀,通过电化学噪声技术(EN)噪声电阻(Rn)和功率谱密度(PSD)等方法研究了Mg2B2O5/AZ31复合材料在中性NaCl溶液中的腐蚀行为。研究表明,浸泡初期(0～24 h),电化学噪声电位、电流在测量时间范围内漂移较小,电位谱功率密度(PSDV)曲线的斜率几乎不变。浸泡后期(24～36 h),电化学噪声出现尖峰波动,谱功率曲线的斜率产生突变,表明电极表面的亚稳态蚀点转化为稳定蚀点。扫描电镜表面形貌分析表明,浸泡36 h后电极表面出现明显蚀点。

Mg2B2O5/AZ31 composite material made electrochemical corrosion under the condition of thermo- mechanical cycling. The corrosion behavior of the Mg2B2O5/AZ31 composite material on NaC1 neutral solution was investigated by some methods, such as electrochemical noise （EN）, noise resistance （R.） and power spectral density （PSI））. The conclusion indicted that in the early of soaked （0 -24 h） , the potential and the current of EN had small draft during measuring time, and the curve slope of potential spectral power density （PSDv ） almost hold the line. But in the late of soaked（24 -36 h）, peak fluctuations appeared in EN, and the curve slope of the PSDv hada sudden change, which showed that metastable erosion point on electrode surface transformed into steady erosion point. SEM measnrements that obvious erosion point appeared on electrode surface after soaked 36h