BS ISO 22910:2020 pdf download – Corrosion of metals and alloys — Measurement of the electrochemical critical localized corrosion temperature (E-CLCT) for Ti alloys fabricated via the additive manufacturing method

BS ISO 22910:2020 pdf download – Corrosion of metals and alloys — Measurement of the electrochemical critical localized corrosion temperature (E-CLCT) for Ti alloys fabricated via the additive manufacturing method 7 Test solutions For the test, 250 g of reagent-grade sodium chloride (NaCl) is dissolved in 750 ml of reagent water, producing an aqueous solution containing 25 % NaCl by mass. The ratio of the volume of solution in the test cell to the specimen area shall be at least 100 ml/cm 2 . 8 Test specimens Any specimen geometry compatible with the specimen holder may be used. Two different test surfaces of the specimen are used, which are made by the layers perpendicular to or parallel to the stacking direction, depending on the stacking direction via AM. A minimum test volume of 10 mm × 10 mm × 1 mm or higher shall be used. A less than 20 % ratio of edge area to total area is desirable. 9 Procedure 9.1 Preparation of reference electrodes The difference in potential between the reference electrode and two other validation electrodes shall be measured. If the potential difference is greater than 3 mV, the test electrodes shall be rejected. 9.2 Preparation of Ti alloy specimen The specimen shall be prepared to ensure a reproducible surface finish. The specimen shall be cleaned immediately prior to immersion in the solution by degreasing, rinsing in high-purity water, followed by ethanol or a similar solvent, and air drying. After degreasing, care shall be taken not to contaminate the test surface of the specimen. 9.3 Preparation of solution The solution shall be prepared using reagent-grade chemicals and reagent-grade water purified to 20 µS/cm by distillation equivalent to type I grade (see ISO 3696). 9.4 Setting up the E-CLCT test The exposed surface area of the specimen shall be measured. Two different test surfaces of the specimen are prepared, comprising layers perpendicular to or parallel to the stacking direction, depending on the stacking direction via AM. The specimen, counter electrode and salt bridge shall be placed in the test cell. The test cell shall be filled with the solution. It is important to ensure that the specimen is immersed and exposed in the solution. The salt bridge is filled with test solution and is free of air bubbles. The solution shall be stirred continuously throughout the test by bubbling an inert gas through the solution at a...