EFFECT OF ANODIZATION TIME OF WASTE ALUMINUM ALLOY BASED PROPELLERS ON CORROSION RESISTANCE

Aluminum waste as a component of ship propeller manufacturing is often faced with the problem of damage due to seawater corrosion. Anodizing methods are required to increase the resistance of the propeller to corrosion. This study was aim to determine the effect of anodizing time on corrosion resistance and alumina layer growth on propellers. The aluminum waste to be anodized is cut according to time variations of (a) 30 minutes, (b) 45 minutes, (c) 60 minutes, and (TP) without treatment with a size of 3cm×3cm×5mm. The tests carried out were corrosion tests (Potentiodynamic Polarization & EIS) and Microstructure Observation (SEM). Results from polarization corrosion and EIS testing on 3.5 wt% NaCl media from samples (a), (b), (c), and (TP). The longer the anodizing time of the sample (c) the polarization test results in a corrosion current (Icorr) of 2.4 × .10-−7. (A/,cm-2.) and its corrosion value is 0.0030 (mmPY). The results of the EIS test obtained 3 graphs, namely the nyquist graph showing that the anodized sample has a graph that tends to be small in the radius of the curve. At the high-frequency range (,10-5.−,10-1.) bode magnitude, sample (c) has a higher magnitude impedance and at a high- frequency phase angle bode of 34.560 Hz indicates sample (c) has a higher phase angle up to -36.403°. The results of microstructure observation (SEM) in samples (a), (b), (c), and (TP). The growth of the alumina layer is seen in the anodized sample. When the corrosion rate value is low, the corrosion resistance value increases. The longer the anodizing time, the more the alumina layer on the surface grows.
Keywords : Anodizing, Propeller, Corrosion, Aluminum Waste, Polarization