The Additional of Inhibitors from Secang (caesalpinia) Leaf Extract in NaOH Solution to Minimize Aluminum Corrosion Rate
Corrosion is a material destruction process because of a reaction between metal and the environment. Iron is a metal that is easily corroded. But metal corrosion is not limited to iron, because there will be a lot of metal that turns out to undergo a corrosion process also one of them is aluminum. Aluminum is a soft and lightweight metal and has a dull silvery color due to the thin layer of oxidation that forms when this element is exposed to air. One corrosion prevention is to use a corrosion inhibitor that can be made using organic materials. Secang (caesalpinia) leaf flowers contain antioxidants such as anthocyanin and ascorbic acid which can be used to prevent or slow down the occurrence of corrosion. The calculation method used in this study is the method of measuring weight loss by gravimetric analysis. This inhibitor is used on aluminum metal which is immersed in 1 M NaOH solution. The concentration of inhibitor of the secang leaf flower is 20 ppm (parts per million) with time variations of 5, 15, 30, 45 and 60 minutes. Corrosion rate on aluminum before the addition of inhibitors with time variations is 0.047, 0.0598, 0.0719, 0.0786 and 0.0688 g / cm.minute. While the corrosion rate on aluminum after the addition of inhibitors namely 0.0356, 0.0465, 0.0536, 0.0757 and 0.0658 g / cm. Minutes with inhibitory power respectively 24.26%, 22.27%, 25.44%, 3.65% and 1.23%. Thus the presence of inhibitors from Secang Leaf Flowers (caesalpinia) causes the rate of corrosion of aluminum soaked in 1 M NaOH solution to be slower.