Electrographic pore testing
In this corrosion test method, the base material is anodically dissolved; the metal ions produced are indicated by an indicator on the surface.
For flat surfaces the test is carried out with impregnated test paper, for profiled parts in a gelled liquid.
In both cases, the size and number of pores is indicated by coloured dots on the paper or in the jelly. The latter method is more sensitive.