Development anti-dairy fouling surface of 316L 2B stainless steel by atmospheric pressure plasma treatment

The development of an antifouling coating for 316L 2B stainless steel pipes used in heat exchangers for milk products was studied in this paper. The coating was obtained using hexamethyldisiloxane (HMDSO) as precursor applied by atmospheric plasma on stainless steel. The stainless steel plates were first pre-treated using nitrogen or air atmospheric pressure plasma to improve the surface properties before coating. Various conditions (distance between plasma source and substrate, aging time and number of passes) were tested to study the influence of these parameters on the surface energy of stainless steel. The HMDSO based coating was then deposited by atmospheric plasma on the pre-treated steel plates and the plates obtained were tested to fouling in a pilot heat-exchanger. Surface response methodology (experimental design) was used in order to identify the optimized coating conditions to minimize the fouling. Mechanical profilometry, Atomic Force Microscopy (AFM), Electron Probe Micro Analyzis (EPMA), Flight-Secondary Ion Mass Spectroscopy (ToF-SIMS), X-Ray Photoelectron Spectrometry (XPS) and goniometry were used to evaluate the coating roughness, morphology, surface energy and chemical composition.