Studi Komparasi Inhibitor Kromat (CrO4), Molybdat (MoO4) Dan Nitrat (NO3) Terhadap Laju Korosi Material Pesawat AA 7050 dalam Media NaCl 3,5 %

Abstract

Aluminum alloy AA 7050 is one of the 7xxx series aluminium alloys and it is widely used as materials for aircraft structures because aluminum is a light metal, which advantages of the relatively high strength and good damage tolerance  and this is a good resistance to corrosion. However, AA 7050 is suffered  from corrosion when is operated in corrosive environments, such as moist air, acid or saline solution. One of the efforts made to control the rate of corrosion is the use of inhibitors. This research aims to study the effect of chromate inhibitor (CrO₄), molybdat (MoO₄) and nitrate (NO₃)  on corrosion rates of the material plane AA 7050 in 3.5% NaCl solution.

Three inhibitors were studied namely chromate (CrO₄), molybdat (MoO₄) and nitrate (NO₃) as an inhibitor is added in a solution of NaCl 3.5% with a various concentration  of  0,1%; 0.3%; 0.5%; and 0.7%. Measurement of corrosion rate using potentiodynamic polarization methods (Tafel plot). As supporting data to test the composition, microstructure test, Vickers hardness test and tensile test.

Results  show that the corrosion rate of AA 7050  3.5% NaCl solution  without the inhibitor in  0,035 mpy. The addition of inhibitor chromat tends to reduce the corrosion rate and among the three inhibitors studied, chromate is the most effective to reduce rate of corrosion and the optimum concentration is reached at a concentration of 0.7 % CrO₄ with minimum corrosion rate of 0.0018 mpy.

Keywords : Aluminum alloy 7050,  NaCl 3.5%,  corrosion inhibitors, CrO₄^2- ,MoO₄^2-, NO₃^2-