Copper Corrosion (60ml) is a test where a finely polished and degreased copper strip is submerged in the sample fluid at a set temperature and duration. The tarnish / corrosion of the strip is determined using a reference of corrosion standards such as the below. The corrosion level is determined in an ascending scale from 1 to 4 each broken into between 2 and 5 letter categories.
Tested On: Any Mineral oil lubricant; typically turbines.
Diagnostic significance: Many lubricating systems use copper in e.g. coolers and connecting tubing as well as components such as bushes and bearings. Corrosion to these parts of a system can ultimately reduce the life of the equipment. It is usually used for compatibility testing of oil for suitability for systems containing copper. Reasons for increased copper corrosion are usually owing to contamination with high sulphur containing compounds or lubricating oils that increase the formation of copper-sulphur tarnish compounds.
Typical Diagnostic limit: 2A on turbine applications. On fuel systems Slight Tarnish (1A and 1B) are maximum allowed.