The effect of vacuum system base pressure of corrosion resistance on SS304L thin films
Advisor:Frankel, Gerald, Jr.
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Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Materials Science and Engineering Honors Theses; 2016
304L stainless steel (SS304L) is a low carbon steel alloy containing chromium and nickel as the main non-iron constituents. It is widely used in industry and life due to its great corrosion resistance, low cost and good ductility. However, SS304L will corrode in the form of crevice or pitting corrosion when exposed to aggressive environments. Meanwhile, recent work has shown that sputter deposited metal films with Nano-sized grains can be more corrosion resistant than bulk samples , and also that base pressure of the sputter deposition system has a large effect on the corrosion resistance of deposited Al thin films . The objective of this research is to find out the effect of base pressure in sputter deposition processing on the corrosion resistance of SS304L thin films. In this research, a sputter deposition tool was used to fabricate nanoscale SS304L films on standard microscope slides. Ferric chloride exposure was used according to ASTM G48 standard for measuring critical pitting temperature, which is an assessment of resistance to pitting corrosion. Optical microscopy was used to observe pitting morphology on the surface of thin films. In addition, potentiodynamic tests were also conducted to obtain polarization curves of samples sputter deposited under different base pressure. According to the work on Al thin films , higher vacuum system base pressure ought to result in higher critical pitting temperature as well as greater corrosion resistance. That research provides evidence that corrosion resistance of thin Al thin film is increased by the intake of oxygen (O) into the film during the sputter deposition. Some works on SS304L reveal that base pressure does not have a significant effect on austenitic stainless steel . However, the thickness of samples used in those works was 20um, which may not be defined as “thin film” perfectly, and the chosen range of base pressure was not as low as that in works on Al. Therefore, this is the motivation of this research to try to find out the effect of base pressure on corrosion resistance of SS304L thin films particularly.
Academic Major: Materials Science and Engineering
G. S. Frankel
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