Salt mist (Test Ka) - resistance of coatings and materials to corrosion in salt aerosol.
The method specifies corrosion-resistance testing of electrotechnical components, equipment and materials in a salt-mist environment. It is used for comparative assessment of metallic materials with or without corrosion protection and reveals discontinuities and defects in metallic, organic, anodic oxide and conversion coatings.
It simulates exposure to salt aerosol, such as in marine environments or winter maintenance of roads and tracks.
The test demonstrates that a coating or material exposed to continuous neutral salt mist under constant conditions for a specified time does not exhibit corrosion beyond the level defined by the specification. It is a comparative test for products of similar construction.
The result does not translate directly into years of service life in a real atmosphere. Severity (exposure time) is selected by the product specification.
A NaCl solution of 50 g/l ±5 g/l (density 1.029–1.036 at 25 °C) with pH 6.5–7.2 measured at 25 °C ±2 K is sprayed in a chamber at 35 °C ±2 K. Spray pressure is 70–170 kPa gauge (typically 98 kPa ±10 kPa), and saturator-tower temperature ranges from 45 °C at 70 kPa to 54 °C at 170 kPa.
Mist fallout is monitored by collectors: 1.5 ml/h ±0.5 ml/h per 80 cm² of horizontal area. Specimens are placed at 20° ±5° from vertical with the tested surface facing upward, after cleaning as specified and without touching the surface by hand.
Sequence: initial measurements (visual inspection, electrical and mechanical checks as required), exposure for the specified time, recovery and final measurements. The report states duration, specimen orientation and exposure method, and measured concentration and pH.
The datasheet must state the exposure time in hours and the post-test assessment criterion (e.g. no substrate corrosion, retained function); without the time, “IEC 60068-2-11” has no comparative value. Chamber conditions (35 °C, 5% NaCl) are fixed for the method, so time is the only variable severity.
