Pengaruh Penambahan Serbuk, Ekstrak dan Senyawa Alkaloid dari Daun Sirsak (Annona Muricata L.) pada Cat sebagai Inhibitor Korosi Besi dalam Medium Natrium Klorida

Abstract

Anticorrosive paints consist of formulations with added organic corrosion inhibitors that aim to improve the protection of metal surfaces from corrosion attack. Currently, organic-based corrosion inhibitors are more used in industrial parts, because organic inhibitors are cheap and environmentally friendly than inorganic inhibitors. This study aims to analyze the use of powder, concentrated extract and alkaloids from soursop leaves in paint on determining the corrosion rate and corrosion inhibition efficiency of iron plate in NaCl media. Soursop leaves contain alkaloid compounds that can act as corrosion inhibitors. Alkaloids have N H and O-H functional groups. The form of inhibitors added to the paint is powder, extracts and alkaloids from soursop leaves with concentrations of 2%, 4%, 6% and 8% and immersion time in 50 mL 3% NaCl media for 2 days, 4 days, 6 days and 8 days. The method used in determining the corrosion rate is the weight reduction method. Based on the results obtained, the lowest corrosion rate of iron plate on immersion in 3% NaCl medium for 8 days amounted to 2.77 mpy. In the coating of iron plate using commercial paint, the lowest corrosion rate of iron plate on immersion in 3% NaCl medium for 8 days was 0.31 mpy. Coating of iron plate using commercial paint on the variation of the addition of powder concentrations, extracts and alkaloids of soursop leaves that produce the lowest corrosion rate on iron plate coating on immersion in 3% NaCl medium for 8 days was obtained with the addition of 8% concentration of 0.25 mpy, 0.12 mpy and 0.06 mpy. The highest efficiency results obtained by coating iron plates using commercial paint on immersion in NaCl medium for 8 days amounted to 88.89%. Coating of iron plates with the addition of powder, extracts and alkaloids from soursop leaves in the paint obtained the highest efficiency at the addition of 8% of 91.11%, 95.56% and 97.78% in 3% NaCl medium for 8 days. Qualitative analysis results showed positive results indicating alkaloids from soursop leaves. FTIR analysis showed that N-H and O-H functional groups were detected in testing soursop leaf powder, commercial paint and paint with the addition of powder and extract from soursop leaves. The results of viscosity analysis on the addition of powder, extract and soursop leaf alkaloids to the paint have viscosity values of 223.5 cST, 194.5 cST and 156.5 cST. The results of SEM analysis showed the morphology of the iron plate and iron plate coated with paint which elements were detected through EDX analysis.