Hi

You can use for preparing a metal sample for TEM examination the Twin-jet electrochemical techniques then Replica techniques. The link could be useful on Replica techniques:

https://www.youtube.com/watch?v=rEG6Y-IRtA0

@ Thomas Breuer, hey. Look, what concerns me is this face.e thickness-through face. It measures 0.8 mm in height. How can i cut a plate for twin-jet eletropolishing?

Dear Qiao

The following procedures could be helpful:

1-you can cut the thickness in a cross sectional way by diamond wheel in a slice ,i.e. a thin sheet, of a um thick range.

2-Then, make a hole in the sliced sheet, by drilling the sheet.

3-Thereafter, anneal the sample according to a standard procedures to get rid off any residual stresses that might raise due to the drilling process.

4-Then apply the Twin-jet electrochemical techniques till the adjacent area surrounding the hole becomes thin enough, nearly transparent, in a few nano-meter scale.

5-Finally examen the sample by TEM.

Hi Qiao,

Observing side face... I think SEM is more appropriate for your purpose. Why you need to use TEM? If you don't have SEM, I think the replica technique is the best as Khaled recommended.

Hi Qiao

We all used FIM to prepare metallic sample for TEM examinations. So,

I am reluctant to say if one could afford to buy TEM, the price of FIM is nothing in a comparison to the TEM price.

Well, classic sample preparation with grinding and electropolishing will also work just fine. You need 3mm sample. Your NiTi sheet is only 0.8 mm. Is that the real question? If so, I suggest: a) cutting the NiTi sheets into stripes and glue them together as for thin film sample (will cause the problems during electropolishing, since glue will remain untact) or b) fix one NiTi sheet into the brass/ceramic tube, as for thin film sample.

Then try to proceed with grinding, electroplishing, etc.

Just a note: for conventional TEM usually NiTi samples will form quite thick layer of Ti-Ni-oxides on the surface. Additional gentle ionmilling will make a huge difference.

(Habib, good FIB can be easily more expensive that cheap C-TEM. Just saying, such comments does not help anyone)

Dear Zavašnik,

How to fix a NiTi sheet into a 3mm brass tube? It will cause the same problems if we just glue it onto the tube.

We find thin area of a niti specimen is very small using twin-jet electropolishing. How to get an enlarged thin area? Does a pre-thining to several microns work?

Best,

Qiao

Hi Li, I'm attaching a low-mag image of NiTi sample, which was first dimpled, then electropolished and finally ion-milled to remove the oxide layer. The last step produced a lot of "curling", but anyway the foil was extremely thin over very large area. I think that was bacause of the pre-thinning (dimpling).

Hi Zavašnik ,

This is a perfect sample. Could please tell me the composition of electropolishing solution? Is the final ion-milling necessary?

Hi Li, the sample was etched in TenuPol-5 with 70:30 Methanol-HN3. The resulting sample was probably good already, but for HR-TEM I tried to remove also the surface oxides. I used PIPS ion mill @ low voltages, less than 1 keV will remove the crystalline oxides but not the amorphous layer. To remove the amophous surface, energies around 500 eV will do, but then it involves some tweaking of ion-mill...