The test standard summaries are for general guidance only. Though believed to be accurate at the time of writing, this may change over time. So this information should not be used as a substitute for referring to a complete test standard, at an appropriate revision level.
Note: the terms salt spray, salt mist & salt fog are all in wide spread use within corrosion test standards. In this context they can be considered to be equivalent and interchangeable terms.
Corrosion test with automatic changeover of humidity & drying phases (Renault)
This is an accelerated laboratory corrosion test method that can be used to determine the corrosion resistance of automotive assemblies and components. This test is cyclic in nature, i.e.; test specimens are exposed to changing climates over time.
Test specimens are placed in an enclosed chamber and exposed to a changing climate that comprises of pollution by chloride ions and exposure to hot/humid and hot/dry atmospheres. The entire test cycle comprises of a main cycle and a sub-cycle. 1 entire test cycle takes 24 hours to execute. The number of entire cycle repeats and therefore the test duration is variable.
The main test cycle begins with 30 minutes of salt spray (pollution) during which a continuous indirect spray of acidic (pH 4.0) salt water solution, falls-out on to the specimens at a rate of 4.0 to 6.0ml/80cm²/hour, in a chamber temperature of +35C. This is followed by 5 minutes of air flushing (purging). This is followed by 5 minutes of wall rinsing, during which the chamber walls are rinsed with deionized water. This is followed by another 5 minutes of air flushing. This is followed by 1 hour 40 minutes of drying in a climate of 20%RH at +35C. This is followed by 1 hour 35 minutes of drying in a climate of 55%RH at +35C.
This is then followed by a repetitive sub-cycle comprising of 1 hour 20 minutes exposure to a humid climate of 90%RH at +35C, followed by 2 hours 40 minutes of drying in a climate of 55%RH at +35C. This sub-cycle is repeated 5 times in total, before the main test cycle starts again.
This Renault test is also referred to as an Essai de Corrosion Cyclique, often abbreviated to ECC-1.