STUDY OF CORROSION RESISTANCE OF TINPLATE AND TIN FREE STEEL IN SOLUTION OF SODIUM CHLORIDE WITH VARIATIONS OF NACL CONCENTRATIONS AND PH OF THE SOLUTION

• Main Author: Aqsal Fahreza, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81126
• Institution: Institut Teknologi Bandung

Tinplate has been used widely in various food products, including canned food, canned drinks, and various other packaging products. Tinplate's good corrosion resistance provides protection from oxidation and dangerous metal contamination into food products which can compromise food quality and safety. However, if the tin layer is damaged or scratched, the base metal can be exposed and has the potential to release iron ions which can cause rust and can cause food contamination due to metal migration from the tinplate into the food which is potentially dangerous to human health. One of the latest innovations in the packaging sector is the use of Tin Free Steel (TFS). Unlike tinplate, TFS does not use a layer of tin in its composition, but is coated with an alternative layer such as chromium, thereby eliminating the risk of heavy metal contamination. Tinplate has a tin coating thickness that varies depending on the food product being packaged, such as tinplate with coating number #10 (TP#10) has a tin coating mass of 1,12 ???????????????????? and tinplate #25 (TP#25) has a tin coating mass of 2,8 ????????????????????. Food packaging in the form of cans is usually also given an additional layer of lacquer which functions to form a protective layer or barrier between the metal and the food. The research carried out was electrochemical testing using the Potentiodynamic Polarization (PDP) method. This research aims to study the corrosion resistance of the corrosion process of tinplate and TFS in sodium chloride (NaCl) solution. The parameters varied in this study were the NaCl concentration and pH of the test solution. The response obtained is the PDP test results curve. These results are then processed using Tafel extrapolation to determine the corrosion potential and corrosion current density. Tafel extrapolation results show that the concentration of NaCl and pH of the solution have an influence on the corrosion rate of tinplate and TFS. The addition of a lacquer layer to the plate can significantly reduce the corrosion current density by ±2.46 ???????????????????????? to reach ±17.27 ???????????????????????? so that the corrosion rate becomes slower. Tinplate with coating number #25 (TP#25) has a corrosion current density that is always high in each different type of test solution so it can be indicated that the corrosion resistance of TP#25 is the lowest compared to TP#10 and TFS so it is susceptible to corrosion. Meanwhile, Tin Free Steel (TFS) has the best corrosion resistance compared to tinplate because of its low corrosion current density.