I’m going to use electropolishing instead of mechanical polishing in my project which is related to aluminum casting alloy (3XX series) and I had some difficulties during the process. So that if any of the researchers have any experience on this case, I would be happy to know his/her opinions on following questions.
What is the best composition of the electrolyte?
What kind of material is suitable for cathode?
What should be the magnitude of the voltage?
How much is the best distance between cathode and anode?
How much time should the specimen be in the electrolyte bath?
Thank for your attention and responding.
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Dear Nima Tabatabaei,
You can try electrolyte Methanol+Nitric acid in the ratio 2:1 with voltage 12-20 V at -30degC for a time of 15-30 s (for a mirror finished-Colloidal Silica-polished sample). The cathode can be Steel or Pt.
Freshly prepared electrolyte works best.
You need to optimize the time and voltage for your sample after different trials.
Anas
Apart from the previous suggestions, you can use electrolyte of 90 ml DI water + 10 ml H3PO4 with 1-8 V DC for 5-10 sec along with the Stainless steel cathode. Use fresh electrolyte for the best result.
Regards,
Manidipto
If the above suggestions don't work then you can use electrolyte Acetone + Perchloric acid in the ratio of 9:1. Best electropolishing happens at the current of 0.7A and 22-25V. If you see the I vs V curve, electropolishing takes place at constant current. So, it is always good practice to do polishing at constant current rather than constant voltage. Generally, 0-5 deg C temperature is good, but you have to adjust it to get output voltage in the range of 22-25V (Nernst equation).
This electrolyte gives a very good mirror like polishing. Stainless steel is suitable for the cathode. 2 minutes time would be good, but it again depends on your material and experimental conditions.
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