Study Of Preparation Of Sub-millimeter Targets And Its Accessories Used In ICF Research

As a method of preparing metal film,electrodeposition is commonly used.It is wid ely used in ICF research,and is the key process of the preparation of targets.In additio n to it's common characteristics,there are some other traits in preparation of ICF targe ts for it's minuteness and abnormity.Firstly,ICF targets and it's accessories is very smal l,and there are usually a lot of corners and steps which leads to severe corner effect. S econdly,for the repuest of physical experiment,the film must be of good quality,includi ng purity,uniformity,compactness and surface smoothness.Thirdly,the tolerance of impurit ies is very low.The area of targets and it's accessories is very small,so little impurities can form a high surface concentration which can make the film quality worse.Especi ally as the development of the research of ICF,the form of targets become more and more complex.This makes the preparation of targets and it's accessories face a lot of new challenges.In this paper,the surface defects were characterized,and the inducing factors were discussed.The damage of impurity to eletrodeposition of targets was analysed.The com position of deposit was tested.We make sure that the element Influenced the quality of deposit were Ti and C.Further the source of impurity was analysed.The method of re flux extraction was employed to remove impurities.The chelating reagent was C9H7NO,t he extract liquid was CHCl3,and the best time of extraction was decided to be three.Influence of e xtraction to the performance of plating solution was studied and it's elementary mechanism wa s analysed.Shortcomings of old plating shelf and the relation between it and defects of deposit were analysed,including abnormal deposit,corrosion of copper base,distribution of current during plating.Influence of Cu and organic impurity on purity and surface q uality were simply analysed. Active carbon adsorption and atmospheric filtration were employed to remove organic impurity and particulate matters.Finally,the reasons of surf ace defect were assigned to be all kinds of impurities and the bad structure of plating shelf.New type of shelf was designed.Morphology of deposit under different current densities was characterized.The infl uence of current density on deposit was analysed.The best range of current density wa s2.4-3.2mA/cm2 when the concentration of gold was 13-22g/L, and 2.0 mA/cm2-2. 6 mA/cm2 when the concentration of gold was 5-13g/L.The influence of predepositio n time and current density on deposit quality were studied.Good quality of deposit wa s prepared when the current density was 7.5mA/cm2 and the time was 1 minute,or the current density was 12.5mA/cm2 and the time was 30 seconds.The influence of base quality on deposit quality was simply analysed.The base should be smooth and degrea sed.The oxidation film should be removed.The influence of HEDP on the morphology of deposit was characterized.It's proved to be feasible to use HEDP to improve the pe rformance of plating solution.The factor resulting in the defect of santong-target was t he daubing of conductive adhesive,and the mechanism was simply discussed.By increas ing temperature and current density step by step,we got the expectant result.The factor s that influence the uniformity of deposit were analysed.New equipment was designed to solve this problem.Feasibility of application of supersonic technology in electrodeposited gold coating was studied.The influence of supersonic on surface quality,current density,deposition speed and performance of plating solution,as well as the mechanism.The shortcomings of the plating equipment used in this chapter was analysed,and new equipment was de signed,which form the base of further experiment.New technology of preparing shield slice and shield barrel were invented. The best formulation and operating parameters were selected.The current waveform and density were optimized. The preparing of shield slice selected direct current and the current d ensity was 2-5mA/cm2. The preparing of shield barrel selected direct current and the current density was 15-30mA/cm2.The reason of deposit blackening was the corrosion of base.The best etching time was 10-20s. Mechanical agitation must be applied at th e early stage of plating.By etching with solution volume ratio 3:1 between HNO3 and HF, metallic cohesion between Ni and Al was increased.By accelerating the separatio n of deposit and base,blackening of deposit was restrained.Non-uniform corrosion and air bubbles led to rupture of shield barrel.New technology of separating Ni and Al wa s invented.By founding mathematical model,factors influenced process were studied,and the heat treatment temperature was 200℃. With the aid of replacement reaction,cohesi on between Ni and Al was reduced.The reason of pinhole was that the replacement re action time was too long,the concentration of additive was too high and anode area w as too small.The replacement reaction time should be no longer than 5min.The adding of additive was optimized.New predeposition technology was invented for the proble m of anode area.