[o8]

Hi, I got my hands on some superconductor material (copper infused with niobium/titanium rods) and was wondering what solution I can use to etch it.  Basically I'd like to make the copper eat away and leave the niobium and titanium rods as pristine as possible.  I've heard ferric chloride can possibly do the trick, but I've never experimented with it.  Any suggestions/advice is welcomed!  Thanks in advance 

[Enthalpy]

I can just confirm that FeCl₃ etches copper. It's used luke-warm in water solution to etch printed circuits. While Nb and Ti use to be resistent, I won't try any forecast about their behaviour in FeCl₃.

One other etchant exists now for printed circuits: ammonium persulfate, but I haven't tried it.

It takes several minutes to etch 35µm away, and superconductors use to cast the fibres in a copper matrix that will be badly accessible, so the operation may need time. Heat accelerates, movement and ultrasound too.