Investigation of corrosion and thermal behavior of PU-PDMS-coated AISI 316L

Abstract

Polydimethylsiloxane (PDMS) is widely used from biomedical to industrial applications due to its nontoxic, hydrophobic, and transparent characteristics. PDMS has good thermal and adhesion properties; however, its mechanical properties are comparatively weak. Therefore, PDMS is blended with various polymers to effectively improve its mechanical properties. In this study, polyurethane (PU)-polydimethylsiloxane (PDMS) blended coatings of different concentrations were applied on the AISI 316L stainless steel surface. Their effects on corrosion and tribocorrosion properties were investigated in Ringer's solutions. The blended polymer coatings were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The thermal properties of samples were examined by TGA and DSC. The surface images and cross-sectional were investigated using scanning electron microscopy (SEM). Tribocorrosion tests were carried out at open circuit potential (OCP). It was determined that hydrophobicity and thermal stability of polymer coating increased, while corrosion resistance slightly decreased with the increasing PDMS concentration in the polymer blended. The friction coefficient of blends decreased as the PU concentration increased. As a result, it was determined that the polymer-coated samples containing up to 50% PDMS prevented corrosive wear under the OCP wear test in Ringer's solutions.