Seikh Asiful H, Sarkar Amit, Singh Jitendra Kumar, Mohammed Sohail M A Khan, Alharthi Nabeel, Ghosh Manojit
Centre of Excellence for Research in Engineering Materials, King Saud University, Riyadh 11421, Saudi Arabia.
Department of Metallurgical and Materials Engineering, Jadavpur University, Kolkata 700032, India.
Materials (Basel). 2019 Feb 6;12(3):503. doi: 10.3390/ma12030503.
The aim of this investigation was to assess the corrosion behavior of gray cast iron (GCI) alloyed with copper. Alloyed GCI specimens were austempered isothermally at varying temperatures. After austenitizing at 927 °C, the samples were austempered at different temperatures ranging from 260 to 385 °C with an interval of 25 °C for 60 minutes. As a result, these samples developed an ausferrite matrix with different percentages of austenite. The resulting microstructures were evaluated and characterized by optical microscope (OM), scanning electron microscope (SEM), and X-ray diffraction (XRD). The corrosion characteristics were determined using potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) of these samples. These tests were carried out in a medium of 0.5 M H₂SO₄ and 3.5% NaCl solution. It was observed from the potentiodynamic polarization results that with increasing austempering temperature, the corrosion rate decreased. All results of the EIS were in accordance with a constant phase element (CPE) model. It was found that with an increase in austempering temperature, the polarization resistance (R) increased. The austenite content was also found to influence the corrosion behavior of the austempered gray cast iron (AGCI).
本研究的目的是评估含铜灰铸铁（GCI）的腐蚀行为。对合金化的GCI试样在不同温度下进行等温奥氏体化处理。在927℃奥氏体化后，将样品在260至385℃的不同温度下进行等温奥氏体化处理，间隔为25℃，保温60分钟。结果，这些样品形成了具有不同奥氏体百分比的贝氏体基体。通过光学显微镜（OM）、扫描电子显微镜（SEM）和X射线衍射（XRD）对所得微观结构进行了评估和表征。使用这些样品的动电位极化测试和电化学阻抗谱（EIS）来确定腐蚀特性。这些测试在0.5 M H₂SO₄和3.5% NaCl溶液介质中进行。从动电位极化结果观察到，随着等温奥氏体化温度的升高，腐蚀速率降低。EIS的所有结果均符合恒相元件（CPE）模型。发现随着等温奥氏体化温度的升高，极化电阻（R）增大。还发现奥氏体含量会影响等温淬火灰铸铁（AGCI）的腐蚀行为。
