Corrosion in a flowing mixed-gas atmosphere (Test Ke) - contacts and connections in polluted air.
A method for testing the corrosive effects of indoor atmospheres (operating and storage environments) on electrotechnical products, their components, equipment and materials, particularly contacts and connections. Specimens are exposed to a flowing mixture of pollutant gases at ppb concentrations (H2S, SO2, NO2, Cl2) under controlled temperature and humidity.
The result supports selection of materials, manufacturing processes and designs for corrosion resistance.
The test demonstrates that contact coatings and connections retain contact resistance and insulation resistance after exposure to a corrosive atmosphere representing a polluted indoor environment. The method accelerates atmospheric corrosion under controlled conditions and allows designs to be compared; acceptance criteria are set by the product specification.
A datasheet entry without method number (1–4) and exposure time does not define severity.
The standard defines four methods differing in gas-mixture composition, temperature and humidity: method 1 (H2S 100 ±20 ppb, SO2 500 ±100 ppb; 25 ±1 °C; 75 ±3% RH), method 2 (H2S 10 ±5 ppb, NO2 200 ±50 ppb, Cl2 10 ±5 ppb; 30 ±1 °C; 70 ±3% RH), method 3 (H2S 100 ±20 ppb, SO2 200 ±20 ppb, NO2 200 ±50 ppb, Cl2 20 ±5 ppb; 30 ±1 °C; 75 ±3% RH) and method 4 (H2S 10 ±5 ppb, NO2 200 ±20 ppb, Cl2 10 ±5 ppb; 25 ±1 °C; 75 ±3% RH).
The chamber provides uniform conditions in the working space and 3–10 air changes per hour, without injection of water droplets or aerosol; exhaust gases are treated. Specimens occupy no more than 10% of chamber volume or working area and are spaced at least 10 mm apart; corrosion is monitored using at least five copper coupons of 0.1–0.2 dm² each, with mass gain weighed to 0.01 mg.
Before testing, contact resistance is measured according to IEC 60512-2-1 and insulation resistance according to IEC 60512-3-1; measurements and visual inspection are repeated after testing. Exposure time is selected from recommended values of 4, 7, 10, 14 and 21 days.
Look for the method number (1–4), exposure time in days and the result (e.g. contact resistance after testing); “IEC 60068-2-60” without method and duration describes only the procedure. The method is relevant to relay contacts, connectors and terminals in control cabinets and equipment boxes exposed to polluted air.
