Development of an Aircraft Lap Joint Simulant Environment

The aging of aircraft fleet has led to significant concern about the development of corrosion. Occluded regions such as lapsplice joints, which are difficult to inspect, are of particular importance. By analyzing the corrosion products found in these joints, a simulant solution has been developed. The lap joint simulant solution (LJSS) contains 20 mM sodium chloride (NaCl), 4 mM sodium bicarbonate (NaHCO₃), 4 mM sodium nitrite (NaNO₂), and 2 mM sodium fluoride (NaF) at pH 9. Exposure of AA2024-T3 (UNS A92024) to the LJSS results in a similar corrosion topography to that found on aircraft in the field.