The benefits of k-Carrageenan-gelatin hybrid composite coating on the medical grade stainless steel (SS304) used as anticorrosive barrier

Biopolymers derived from seaweed are good anticorrosive, antibacterial and anticancer agents. These biopolymers family includes the k-Carrageenan with good potential anticorrosive feature that is extracted from the red seaweed Acanthophora spicifera - Rhodophyceae. To obtain the best corrosion inhibition properties the k –Carrageenan hybrid composite with gelatin was prepared by sol-gel method. In the present study, two natural compounds have been used to prepare the proposed hybrid composite material. Such as, a self-assembled multilayer coating for medical grade stainless steel (SS) 304 were formed as substrate which can resist successfully to mild condition (3.5 wt % of NaCl) in the chosen electrolyte medium. The analysis by FT-IR confirms the hybridation of gelatin and biopolymer of k -Carrageenan. The electrochemical results revealed that the coated SS 304 is a promising corrosion inhibition with an efficiency up to 97% at 24h and up to 65% at 227 h. The E _oc values from open circuit potential analysis indicated the occurrence of passivation on the surface due to hybrid composite coating. Further, the electrochemical impedance spectroscopy showed that the resistance of hybrid composite is higher than the bare steel showing R _ct of 6.1 kΩ ⋅ cm ² and 2.1 kΩ ⋅ cm ², respectively. The microstructural analysis by Scanning Electron Microscopy (SEM) and atomic force microscopy (AFM) confirmed that the coating surface have better corrosion resistance than SS 304 bare metal.