Copper Corrosion test

DIN 51811 Copper corrosion test is used to determine the grease’s ability to protect sensitive metals (copper/yellow metals) and other soft alloys typically found in bush bearings and electrical contacts.
A polished copper strip is exposed to the grease for a specific time and temperature, usually 24 hours at 100 to 120°C.
Key Aspects of the Test Method
• A clean, polished copper strip is submerged in the grease sample
• The sample is heated in a controlled bath or oven, for example at 100°C for 24 hours
• After heating, the strip is cleaned (e.g., with acetone) and its color compared to official ASTM/DIN charts
• The colour change observed on the copper test strip is rated numerically and alphabetically (e.g., 1a for best, up to 4c for severe corrosion).
Standards Alignment:
DIN 51811 is similar to or harmonized with other major standards like ASTM D130, D4048, D7095, EN/ISO 2160, and IP 154.
The test measures ability of the grease to inhibit copper corrosion over time without considering other factors.