2,315
edits
Changes
→Porosity
During the electrolytic test, a sample is immersed into an electrolyte, containing an indicator solution. After passing electrical current, the pores are visible as colored spots.
Frequently a SO test at higher concentrations (100 ppm) and high humidity (2 levels, 95% RH at 40°C) is used. One advantage of this method is, that the severity level can be increased easily by varying the concentration of SO<sub>2</sub>. Besides these, other corrosive gas mixtures of H<sub>2</sub>S, SO<sub>2</sub>, and NO<sub>2</sub> are used in porosity tests (i.e. tests according to ASTM B735 and B 799).
====<!--13.2.1.3-->Hardness====
