The standard electrolyte I use for electropolishing of titanium alloys such as Ti-5553 is HCl+CH3COOH (less hazardous than methanol based). I can get mirror like surface finish visually. But on SEM i see dimples roughly 50nm in diameter (picture attached). Can someone give me insight at why are they formed and how to electropolish the specimen without them?
This image is taken at very high current try to use smaller one for better picture. Why those dimples are problem? What polishing parameters current voltage temperature do you use? Have you tried A3 electrolyte by Struers?
The problem with dimples is that when I try to examine the fine precipitates like secondary alpha phase after low temperature aging i can't actually make any useful picture at high magnifications because the width of the alpha laths is comparable or smaller than dimples diameter. The standard polishing parameters is 60..70V, 4-5 A current, -10...-5 degrees Celsius. (Tried different parameters, but couldn't find anything better) No, the electrolyte I use is all I have for now. Can the A3 produce different results? The actual question is that can I somehow get the surface without dimples or is it the default artifact of electropolishing and you can't do anything about it. If so then maybe electropolishing is not very suitable for the task and i should stick with the mechanical polishing though it takes more time...
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