View source for Electropolishing TEM sample (Al alloy)

[[Category: SOP]]

The following is an SOP for the electropolishing TEM sample preparation (Al alloy preferred).

=Loss Prevention=
*Electrolyte contains Perchloric acid, be really careful when using it. Wear full PPE (laboratory coat, full face mask, gloves).
**Highly corrosive and causes severe burns in contact with skin, eyes or mucous membranes or if swallowed/inhaled.
**Unstable above 33 °C. Concentrated solutions may react explosively with wood or paper above this temperature. Remember using an ice bath when making electrolyte.

=Procedure=
# Prepare a 1:4 mixture of reagent grade perchloric acid to reagent grade methanol. The detail of how to prepare the electrolyte is written in the polisher manual. I will add it here later.
# Pour the electrolyte into the electrolytic solution tank in the fume cupboard. Insert the thermometer into the tank to read the temperature of the electrolyte.
#* [[File:Polishing cell.png|1000px|thumb|center|Polishing cell]]{{clear}}
# Fill the chiller container with liquid nitrogen, turn the fan on for the cooling line. The switch of the fan is on the polisher panel. Adjust the speed of the fan by spinning knob “UNIPUMP” above the switch to keep temperature maintained at the desired level. Keep the electrolyte below -30°C for each run.
#* [[File:Polisher power.jpg|1000px|thumb|center|Polisher power]]
# Place the sample at the center of the sample holder and tighten it by the screw.
#* [[File:Sample holder.png|1000px|thumb|center|Sample holder]]
# Inset the sample holder into the solution tank from the top. Connect the top of the sample holder to the clip of the polishing cell. 
#* [[File:Connect sample holder.png|1000px|thumb|center|Connect sample holder]]
# Turn the “METALTHIN” on using the key in that. Turn “JET STARTS” on, parameters settings list below:
#*DC OUTPUT (voltage, on display): 15-25 v
#*Sensitivity: 6-7
#*Jet speed: 4
# Press “TRIPPED reset” and the polishing should start. The polishing will finish once the light goes off.
# Unconnected sample holder to clip and take the sample out, clean sample using methanol.
# After electropolishing work finished, discard electrolyte as instructed in the electropolishing manual.