Corrosion Of Aluminum Hardware

Client Problem:

The client received a large number of customer returns of interior window hardware due to corrosion. Investigation by the client revealed that all of the hardware returns were from one installation site.

Analysis:

Visual examination of the returned hardware showed extensive corrosion of the aluminum base metal and significant corrosion debris.

Elemental analyses by inductively coupled plasma (ICP) spectroscopy indicated that the hardware base metal composition was as specified. Analysis of uncorroded surfaces of the hardware by Fourier transform infrared (FTIR) spectroscopy detected the presence of the specified lacquer finish. Elemental analyses of the corrosion debris by energy dispersive spectroscopy (EDS) detected the presence of potassium, sodium, and chlorine; in addition to aluminum (hydr)oxides.

The presence of potassium, sodium, and chlorine suggests that the aluminum hardware may have been exposed to a chlorinated alkaline cleaner which resulted in the observed corrosion after aggressive scrubbing breached the protective surface layer.

Customer Benefit:

The customer was able to confirm that the hardware was cleaned on site using Oxyclean, a chlorinated alkaline commercial cleaner containing potassium hydroxide, sodium hydroxide, and sodium hypochlorite. The customer has the option of specifically warning against the use of chlorinated alkaline cleansers or providing a more abrasion resistant finish, such as anodizing, on the hardware.

January 31, 2010 by Tim Kenney

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