The Corrosion Behavior of Thermal Spray Coating on 304L Stainless Steel in a Saline Environment

The corrosion behaviors of the thermal spray coatings on 304L stainless steel by two different processes were studied in a saline environment. Austenitic 304L stainless steel has been extensively used as a structural material. To improve its corrosion resistance in the marine environment, an arc spray and an HVOF thermal spray processes were employed to apply a corrosion-resistant coat on the 304L stainless steel specimens. To evaluate the corrosion resistance of the thermal spray layers, the coated specimens were deposited with NaCl of about 0.025g/cm² and tested in an environment chamber at a constant temperature 80^oC and relative humidity 80% for up to 1000h. After corrosion testing, the morphology of the coated surface was examined with an optical microscope and X-ray diffractometer (XRD) to investigate the corrosion behavior of the coatings. The electrochemical polarization curves were also determined to evaluate the corrosion resistance of the thermal spray layers.