Effect of Phenolic Resin Coating Thickness on Mechanical Properties and Corrosion Resistance of Metal Materials

In the realm of petrochemical and other industries, metal materials face threats such as impact and high-temperature electrochemical corrosion. Consequently, there has been significant attention towards organic coatings that effectively attenuate impact forces while simultaneously providing a barrier against corrosive agents. The thermosetting phenolic resin 2130, known for the facile curing process, exceptional thermal stability, water resistance, corrosion resistance, and superior mechanical properties post-curing, finds extensive applications in the field of coatings. To address the challenge of depositing a complete and uniform resin coating on complex workpieces, coatings with varying thicknesses on the surface of 304 stainless steel were deposited via rotary evaporation combined with long-term low-temperature drying. The relationship between coating thickness and mechanical properties, as well as corrosion resistance, was investigated and analyzed through a comprehensive approach involving mechanical testing, electrochemical analysis, and long-term service weight loss assessment. The results demonstrated that the coatings deposited on the metal surface exhibited excellent integrity and compactness. Moreover, an increase in coating thickness led to a significant reduction in material corrosion rate. The coatings exhibited excellent substrate adhesion and flexibility, thereby providing effective protection against impact on the metal substrate. The relationship between the thickness of the coating and the surface roughness was evident, while the flexibility of the coating first increased and then decreased with the increase of coating thickness. When the coating thickness was 7 μm, the maximum surface roughness of the coating measured 0.44 μm. Under these conditions, the impact toughness of the coating reached the peak, exhibiting a ductile fracture mode and showcasing superior comprehensive mechanical properties. The findings of this study will offer theoretical support for the investigation and formulation of resin coatings in subsequent industrial production.