5.4.3 Determination of mass loss (m

5.4.3 Determination of mass loss (mass per area)At the end of the test, immediately take the reference specimens out of the test cabinet and remove the protective coating. Remove the corrosion products by mechanical and chemical cleaning as described in ISO 8407. For chemical cleaning, use a solution with a mass fraction of 20 % of diammonium citrate [(NH4)2HC6H5O7] (recognized analytical grade) in water for 10 min at 23 °C.After each stripping, thoroughly clean the reference specimens at ambient temperature with water, then with ethanol, followed by drying.Weigh the reference specimens to the nearest 1 mg. Divide the determined mass loss by the area of the exposed surface area of the reference specimen in order to assess the metal mass loss per square metre of the reference specimen.It is recommended to use freshly prepared solution during every procedure for removal of corrosion products.NOTE The corrosion products can also be removed by chemical cleaning as described in ISO 8407, and by using a solution with a volume fraction of 50 % hydrochloric acid (ρ20 = 1,18 g/ml), of recognized analytical grade, in water, the latter also containing 3,5 g/l of hexamethylene tetramine as a corrosion inhibitor.