Corrosion Performance of Steel and Stainless Steel for Long-Life Electric Vehicle Components in Atmospheric Conditions

This study aims to determine the atmospheric corrosion rates of ST37 carbon steel and SS304 stainless steel using a salt spray chamber designed in accordance with ASTM B117 standards. Two test solutions such as NaCl and MgCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> were selected to simulate saline environments and compare the effects of different salt compositions representative of artificial seawater. Corrosion tests were conducted over a total duration of 48 hours, with time variables of 4, 6, and 8 hours per cycle. Post-exposure evaluations included macroscopic observation, optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Weight loss measurements for ST37 were performed after removing corrosion products using HCl solution in accordance with ASTM G1 standards. The results showed that corrosion rates varied slightly between solutions and exposure times. For NaCl, average rates were 18.6945 mmpy (4 h) and 21.4720 mmpy (6 h), while MgCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> yielded 21.0120 mmpy (4 h) and 24.3440 mmpy (6 h). MgCl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> consistently produced higher corrosion rates compared to NaCl. Among the tested materials, SS304 exhibited significantly higher resistance to atmospheric corrosion than ST37. The acrylic material used for the salt spray chamber demonstrated high corrosion resistance, remaining unaffected by the testing environment. These findings provide comparative insights into the performance of steel and stainless steel under accelerated atmospheric corrosion conditions, relevant for material selection in long-life applications.