锻态和SLMed TC4合金在3.5wt.%NaCl溶液中的腐蚀行为

Corrosion behavior of as-forged and SLMed TC4 alloys in 3.5 wt.% NaCl solution

利用电化学阻抗谱、动电位极化曲线、微区电化学阻抗技术对锻态和SLMed TC4合金在3.5wt.%NaCl溶液中的电化学行为进行了研究,并利用Mott-Schottky测试、X射线光电子能谱仪对其表面钝化膜进行了分析。结果表明:锻态TC4合金为α+β双相结构,而SLMed TC4合金则主要由针状α′马氏体组成;与SLMed TC4合金相比,锻态合金的极化电阻更高,腐蚀电流密度更低,钝化膜更厚。两种合金表面的钝化膜均为n型半导体,但锻造合金的载流子密度更低,且钝化膜中TiO_(2)的含量更高,这表明锻态TC4合金的耐腐蚀性能优于SLMed TC4合金。

The electrochemical impedance spectroscopy(EIS),potentiodynamic polarization curves(PDP),and localized electrochemical impedance spectroscopy(LEIS)were utilized to investigate the electrochemical behavior of as-forged and selective laser-melted(SLMed)TC4 alloys in 3.5wt.%NaCl solution.Additionally,Mott-Schottky test and X-ray photoelectron spectroscopy(XPS)were employed to analyze the properties of the passive films formed on the surface of the alloys.The results indicated that the as-forged TC4 alloy possessed an α+β dual-phase structure,whereas the SLMed TC4 alloy was mainly composed of acicular α' martensite.Compared to the SLMed TC4 alloy,the as-forged TC4 alloy exhibited a higher polarization resistance,a lower corrosion current density,and a thicker passive film.The passive films on both alloys were found to be n-type semiconductors,but the as-forged alloy had a lower carrier density.The content of TiO_(2) in passive film was also higher,indicating that the corrosion resistance property of the as-forged TC4 alloy was better than that of SLMed TC4 alloy.