Early corrosion failure of copper tubing used in air-conditioning units

Abstract

This paper analyses the causes of the early corrosion failure of phosphorus deoxidized copper tubes which formed part of an air-conditioning unit. The failure of the tubes occurred after 2-3 months service time. X-ray photo-electron spectroscopy (XPS), Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were used. Corrosion tests were also performed at the laboratory using three types of uncorroded copper tubes, 40, 80 and 100% relative humidities, 20 and 40 °C temperature, and two commercial lubricant oils. Organic acids, chloride and sulphur were found as sources of corrosion failure. © WILEY-VCH Verlag GmbH,.