In situ corrosion monitoring of Ti–6Al–4V alloy in H₂SO₄/HCl mixed solution using electrochemical AFM

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• 作者：Jhen-Rong Chen^a ; Wen-Ta Tsai ; ^a ; ^{wttsai@mail.ncku.edu.tw}
• 关键词：In situ corrosion monitoring ; ECAFM ; Ti&#x2013 ; 6Al&#x2013 ; 4V alloy ; Selective corrosion ; Galvanic effect
• 刊名：Electrochimica Acta
• 出版年：2011
• 出版时间：15 January 2011
• 年：2011
• 卷：56
• 期：4
• 页码：1746-1751
• 全文大小：1021 K

文摘

Electrochemical atomic force microscope (ECAFM) was employed for in situ observation of corrosion of solution annealed and furnace cooled Ti–6Al–4V titanium alloy in 0.5 mol l⁻¹ H₂SO₄ + 1 mol l⁻¹ HCl mixed solution. A scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) was also used for microstructure examination and chemical composition analysis. For solution annealed followed by furnace-cooled Ti–6Al–4V titanium alloy, selective corrosion of α phase and galvanic effect at α/β interface could be clearly observed at open circuit potential under ECAFM. A higher dissolution rate was also found in α phase than β phase on the bare Ti–6Al–4V titanium alloy. The effect of potential on the corrosion behavior was also explored. Negligible corrosion was found after potentiostatic etching at −0.5 and −0.85 V_Pt for 120 min. However, selective dissolution of α phase with respect to β phase occurred when the potential was controlled at −0.9 V_Pt. The polarity inversion during potentiostatic etching at −0.9 V_Pt was also found and discussed in this study.