THE EFFECT OF CURRENT DENSITY ON MORPHOLOGY, THICKNESS, AND CORROSION RESISTANCE IN ANODIZING ALUMINUM 2024-T3 USING CHROMIC ACID

• Main Author: Mardianto, Wido
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/74109
• Institution: Institut Teknologi Bandung

Aluminium alloy 2024 is commonly used in applications that require a high strength-to-weight ratio, such as the aerospace industry. One of the challenges in using aluminium alloy 2024 is its low corrosion resistance. This can be controlled by forming an aluminium oxide layer. One method of creating this layer is through anodizing. Anodizing in chromic acid solution is widely used in aerospace applications. However, even with effective anodization processes, the resulting corrosion resistance often falls short. Therefore, this is an important challenge in the aerospace industry. In this study, the effect of varying anodization current density on the corrosion resistance of the oxide layer has been investigated using electrochemical methods (OCP, EIS, and Cyclic Polarization). The morphology and thickness of the anodized aluminium oxide layer will be observed using an electron microscope. The anodization process conducted with varying current densities of 0.5, 1, 2, and 3 A/dm2. The research findings indicate that an increase in the current density during anodization from 0.5 to 3 A/dm2 results in a thicker oxide layer, ranging from 2.18 to 5 microns. Furthermore, the corrosion resistance of the layer increases with the increasing current density during anodization. The OCP values of the layer range from -0.551 to -0.113 V vs. Ag/AgCl. The pitting potential of the layer ranges from 0.013 to 0.973 V vs. Ag/AgCl. The EIS results shown an approximately 75% (0.8 – 1.4 M?) increase in layer impedance in 3.5% NaCl electrolyte and 1000% (0.2 – 2.2 M?) in 3.5% NaCl + 100 ppm Na2SO4. This research should be further investigated in the future.