To prepare an epoxy embedded sample for corrosion testing, what should be the grit size of abrasion paper to smoothen the surface of metal.
Why should we use a particular abrasion paper?
Dear Hashim,
You may find answers to your questions in our scriptum "Preparation_methods_in_Mineralogy_Geology_" by Guenter Grundmann and Herbert Scholz (see link below).
What kind of corrosion should be tested?
Best regards,
Guenter Grundmann
Data Preparation methods in Mineralogy & Geology: The Preparation...
Dear Hashim, there exist special ISO recommendations for the preparation of corrosion tests by using polishing paper. The reason for the treatment is that superficial contamination on the surface is influencing the response; the surface is in direct contact with the electrolyte. However, in the case of copper samples, we have found that SiC polishing is not a good method: The metal is very soft and particles from the polishing paper get stuck in the metal and cannot be easily removed even supersonically. Their presence was detected both by grazing incidence XRD (phase analysis) and by XPS (elemental analysis). Even if original contaminating species were removed by such a polishing procedure, that very process introduced new ones (and they might influence the experiment). To avoid that problem, you should best use diamond particles which cannot disturb the V-I characteristics because they are inert and do not participate in your kind of experiment. The grit size is of importance if you consider how much you disturb the sample mechanically or in what degree you change the actual surface size (the nominal you can measure under a microscope). Considering these aspects you should always end with a small size of the particles.
The preparation of geological samples that Grundmann refers to has other aspects (not the least optically) that might have to be weighed in, depending on what you are to study. In general, all advice should be valued and evaluated, even if it is not at first glance connected to your own field of study. Not the least one may get unexpected new ideas...
Kind regards
Rolf Berger
It depends on the purpose of your work. "Clean" corrosion tests require very accurate and well-defined surface preparation. If an industrial aspect is important you need to prepare the surface to adapt to the actual conditions. The method of surface preparation also depends on the type of metal or alloy. You also need to take into consideration further steps in surface preparation, eg aluminum etching and passivation. Rolf Berger's answer is very interesting and can be helpful for research.
Kind regards
stefan krakowiak
Hi Hashim
First, you should follow the standard article you will use.
If you will use the same sample for SEM, TEM or XPS you need to have a mirror-face.
Here the procedure I use, abrasion paper no. 240 then 600 for corrosion only if you will apply another analysis then use 2400-4000 to get mirror-face.
I also would like to say epoxy is not the best way to mold corrosion sample in, it usually suffers from crevice corrosion.
Regards
Gobara
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