Efektivitas Inhibitor Ektrak Daun Ketapang (Terminalia Catappa) Untuk Perlindungan Korosi Baja Astm A36 Dalam Media H2SO4

Corrosion is a material degradation that occurs in a metal due to a chemical or electrochemical reaction with its environment. Corrosion in industry, among others, can attack storage tanks made of ASTM A36 steel. Coating can be done as a way to minimize the occurrence of corrosion, namely by coating the metal surface so as to prevent direct contact with the environment. Coatings that are often used are coatings using paint, but paints are made of chemical compounds that can affect the environment, so research needs to be done to reduce the use of chemicals with more organic materials. In this study, ketapang leaves which are known to contain tannin were used as coatings on ASTM A36 steel. Test specimens with various conditions, namely without coating, paint coating, coating ketapang leaf extract and coating mixture of ketapang leaf extract and paint 30%, 50%, and 70% soaked in H2SO4 for 25 days. The results showed that coating using ketapang leaf extract could reduce the corrosion rate on ASTM A 36 steel. This was indicated by the decrease in the corrosion rate to 0.0207 mm/y at 5 days immersion 0.0164 mm/y at 10 days immersion compared to the object. test without coating which has a corrosion rate of 0.0247 mm/y at 5 days immersion 0.0167 mm/y at 10 days immersion. A mixture of paint and ketapang leaf extract can be used as a protective layer for ASTM A36 steel plate shown by the lowest corrosion rate at 70% concentration of ketapang leaf extract. The color change of the corrosion medium was caused by the ketapang leaf extract being mixed into the corrosive media so that it functions as an inhibitor. However, even though the corrosion rate is not the lowest, a mixture of paint with 30% ketapang leaf extract has advantages because the adhesive power of the paint is relatively more stable