Joseph Olufunmilayo O, Loto Cleophas A, Sivaprasad Seetharaman, Ajayi John A, Tarafder Soumitra
Department of Mechanical Engineering, College of Engineering, Covenant University, P.M.B. 1023, Canaanland 112212, Nigeria.
Materials Science and Technology Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India.
Materials (Basel). 2016 Jun 16;9(6):463. doi: 10.3390/ma9060463.
In this study, micro-alloyed steel (MAS) material normally used in the production of auto parts has been immersed in an E80 simulated fuel grade ethanol (SFGE) environment and its degradation mechanism in the presence of sodium chloride (NaCl) was evaluated. Corrosion behavior was determined through mass loss tests and electrochemical measurements with respect to a reference test in the absence of NaCl. Fracture behavior was determined via J-integral tests with three-point bend specimens at an ambient temperature of 27 °C. The mass loss of MAS increased in E80 with NaCl up to a concentration of 32 mg/L; beyond that threshold, the effect of increasing chloride was insignificant. MAS did not demonstrate distinct passivation behavior, as well as pitting potential with anodic polarization, in the range of the ethanol-chloride ratio. Chloride caused pitting in MAS. The fracture resistance of MAS reduced in E80 with increasing chloride. Crack tip blunting decreased with increasing chloride, thus accounting for the reduction in fracture toughness.
在本研究中，通常用于汽车零部件生产的微合金钢（MAS）材料被浸泡在E80模拟燃料级乙醇（SFGE）环境中，并评估了其在氯化钠（NaCl）存在下的降解机制。通过质量损失试验和电化学测量确定了相对于无NaCl的参考试验的腐蚀行为。通过在27℃环境温度下对三点弯曲试样进行J积分试验确定了断裂行为。在E80中，随着NaCl浓度增加至32mg/L，MAS的质量损失增加；超过该阈值后，氯化物增加的影响不显著。在乙醇 - 氯化物比例范围内，MAS未表现出明显的钝化行为以及阳极极化点蚀电位。氯化物导致MAS出现点蚀。在E80中，随着氯化物含量增加，MAS的抗断裂能力降低。随着氯化物含量增加，裂纹尖端钝化减小，从而导致断裂韧性降低。
