The Preparation Of Ultrafine Tungsten Wire By Electropolishing Mothed In An Ionic Liquid

Since the nineties of the last century, a great breakthrough has been achieved in theresearch of Z-pinch driven inertial confinement fusion (ICF). The target chamber load,as a key part, determines the rate of converting laser light to the X-ray conversion sothat the research about the target chamber load never aborted about. Tungsten is a kindof excellent material for the preparation of target chamber load wires, for its propertiesof high melting point, hardness, heat resistance, resistance to corrosion as well as goodelectrical conductivity properties, etc., In order to meet the requirements of the ICFphysics experiments, the ultrafine tungsten filaments of less than10microns in diameterare needed, and the diameter roundness should be uniform, surface should be smooth.This paper is focused on the preparation of ultrafine tungsten wire, the study aboutelectrodeposition of gold on the ultrafine tungsten wire surface and the exploration onthe mechanism of corrosion reaction in the process of preparation of ultra-fine tungsten.An electrochemistry method was used in the process of preparing ultrafinetungsten wire in choline chloride-ethylene glycol ionic liquids. Before preparation, theconductive properties of chloride-ethylene glycol ionic liquids was tested first, thenusing a three-electrode electrochemical workstation system for tungsten wire as theanode, the stainless steel cylinder barrel (homemade) as a cathode, anhydrous electrodeof silver/silver nitrate (homemade) as a reference electrode, to test the electrolysisvoltage for tungsten corrosion. Set the applied voltage and reaction time to the requiredby electrolytic polishing, then the desired diameter tungsten wire could be obtained afterthe reaction. The process of preparing ultrafine tungsten with a uniform reduceddiameter is similar with the description above. It just needed to add a pulling apparatusfix on the anode, and set one of appropriate pulling rate. Use SEM, XRD method toanalysis the surface morphology and microstructue of atoms at the tungsten wiresurface.This paper has discussed the corrosion mechanism of tungsten electrode byresearching tafel curves, linear sweep voltammetry curves and AC impedance.Compared with the tafel curve obtained in the alkaline solution, the high corrosion potential has been seen in the tafel curve which obtained in the ionic liquid suggestedthat the corrosion resistance of tungsten can be stronger. It is shown that theelectrochemical behavior of tungsten anode is different from the sample in the aqueous systemand no passivation plateaus were observed in the LSV, indicating a new mechanism of tungstendissolved. Analysis about the result of AC impedance experiments, it found that the masstransfer processthe is step of controlling the speed of the entire reaction in the electrolyticpolishing process.Finally, this paper has studied the electrodeposition of Au ion on the surface of ultrafinetungsten wire in the aqueous solution of gold potassium citrate and ionic liquid system,respectively. The electrodeposition of gold on tungsten wire surface is relatively easy to operatein aqueous bath, as long as a weak reduction current through the system, gold ions could bedeposited on tungsten surface. The similar station has been occurred in the ionic liquid goldplating solution. Observation of the microstructure of the coating by SEM, it can be seen adense and uniform coating with no cracks and pores appeared.