How to Prepare Tungsten Needle?

How to prepare tungsten needle? You should prepare the following materials at first:

Reagents: Potassium nitrite (KNO2) solution, saturated, prepared in water. Alternatively, use 1 N NaOH.

Equipment: Clips, alligator; dish, porcelain; ethanol burner; forceps, fine; power cable; stereomicroscope; transformer, alternating current, capable of generating 4-8 V and up to 5 A; tripod; platinum wire; tungsten wire of 0.1- to 0.2-mm diameter.

More details, please visit:
http://tungsten.com.cn/tungsten-needles.html

A Preparation Method of Tungsten Needle

Step One: Clamp a 3- to 4-cm piece of tungsten wire in an alligator clip fixed to a tripod. Clamp a 3- to 4-cm piece of platinum wire in another alligator clip fixed to a tripod.

Step Two: Submerge the tip of the platinum wire in a porcelain dish filled with the saturated KNO2 solution (or 1 N NaOH).

Step Three: Connect the power cables of the alligator clips to the transformer.

Step Four: While monitoring under a stereomicroscope, dip the tip of the tungsten wire repeatedly in the KNO2 solution to obtain a 2- to 3-mm-long conus with the desired sharpness.

Step Five: Using fine forceps, place the sharpened tungsten needle into the opening of the capillary pipette.

Step Six: Using an ethanol burner, melt the glass around the needle, fixing it into place.

Step Seven: Wash the tungsten needle extensively in water to remove any residual salt crystals.

• < Prev
• Next >