Wednesday, August 25, 2010

Heating holder ruthenium-salt experiment

In a previous post I reported on how we made an old heating sample holder Jeol EM-SHH to function by replacing the electronic with LabView and PXI measurement system. Here I report on the first results of a new upcoming experiment.

Background
Ruthenium together with different other substances are often used due to it's catalytic properties and is for example applied in electrodes used for electrochemical reactions. In electrochemical processes, large area of the electrode is preferred as this scales with production. To create large areas, usually porous structures on the electrode surface are constructed by different processes, heating in furnace is one of them.


A thin film of the salt-mixture were deposited on a silicon nitride TEM grid. Here we test the heating holder by heating up this ruthenium-salt mixture to above 700 °C.

Result
We made a movie of the experiment, at the bottom of the movie screen you see the heating temperature.
Two important observations were made:

  1. At 14 seconds into the movie, the ruthenium-film crystalizes at the beginning the film was amorphous.
  2. Nanoparticles were formed late in the movie, and at 41 seconds, these particles can be seen to coalescence.  

Conclusion
The sample heating holder appears to function properly.

Supplementary
The metallic springs used to fix the sample in the holder were lost, before I received it. New springs were made by winding a 0.25 mm platinum/iridium wire around a small screwdriver, this seemed to work properly.

Whats next
Next I will repport on how to introduce an optical fiber into the electron microscope, used for temperature measurements or laser treatment in-situ.

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