發(fā)布時間：2018-12-13 13:26

【摘要】：慣性約束聚變（ICF）實驗用靶的制備過程中，點火靶以活潑金屬鈾或其合金作為能量轉(zhuǎn)換材料，在轉(zhuǎn)換層材料表面需沉積一層化學性質(zhì)穩(wěn)定的單質(zhì)金作為支撐層。由于鈾基體有較強活性，表面易形成氧化膜，在傳統(tǒng)的水溶液體系中電沉積很難獲得結(jié)合力符合要求的鍍層。故開發(fā)新型的非水電鍍金體系勢在必行。 本文分別以基于氯化膽堿的Reline和Ethaline離子液體為溶劑，以氯金酸鈉為主鹽，二甲基海因（DMH）為配位劑進行了電鍍金工藝的探究，分別研究了主鹽濃度、配位劑含量等鍍液組成及溫度、電流密度等工藝條件對鍍層性能的影響。 在Reline離子液體中，通過正交試驗確定了基本鍍液體系，其中Au3+4g/L，DMH45g/L，氯化鋰15g/L，沉積電勢為-1.4V(vs. Pt)。通過單因素試驗，發(fā)現(xiàn)電流密度及鍍液溫度對鍍層外觀質(zhì)量影響較大，而氯化鋰濃度的影響較小。在基本鍍液中，以鎳為基體，可以電沉積獲得較為均一細致的鍍金層，但工作電流密度較小，電流密度區(qū)間較窄。嘗試了通過提高主鹽濃度、鍍液溫度，加入稀釋劑等方法來提高電流密度，結(jié)果表明工作電流密度很難提高。 在Ethaline離子液體中，通過大量實驗初步確定了基本鍍液體系，組成為Au30g/L，DMH156g/L，Na2CO35g/L。在基本鍍液中，在電流密度2~10mA/cm2范圍內(nèi)可得到金黃色的鍍金層，而電流為6.5mA/cm2時得到的金層的均一性最好。以鎳為基體時，陰極片表面容易出現(xiàn)漏鍍區(qū)，產(chǎn)生黑色區(qū)域，，而以金為基體時，則容易得到均一細致的鍍金層。提高主鹽濃度、鍍液溫度可大幅提高工作電流密度，而隨著溫度的升高，鍍層外觀質(zhì)量有所改善，最佳鍍液溫度范圍為90~100℃。另外，由于高濃度的Au3+具有強氧化性，陰、陽極過程出現(xiàn)異�，F(xiàn)象：新配置鍍液中，陰極沉積效率非常低，甚至接近0，而金陽極溶解效率大于100%。 利用XRD對鍍層的晶體結(jié)構(gòu)進行了分析，發(fā)現(xiàn)兩體系中所得金層均為面心立方結(jié)構(gòu)。通過XPS、XRF及EDS對鍍層成分進行了分析，并利用SIMS對鍍層成分作了深度分析，發(fā)現(xiàn)鍍金層比較純凈，無有機物夾雜。另外，利用SEM、AFM對鍍層的微觀形貌進行了表征。 通過循環(huán)伏安（CV）方法對體系中金的還原機理以及電極的可逆性進行了研究，發(fā)現(xiàn)Au3+的還原是分步，存在Au+中間體，且還原過程為非可逆的；利用LSV方法研究了糖精鈉與丁炔二醇對陰極極化的影響，表明糖精鈉與丁炔二醇對提高陰極極化的作用效果不大；利用計時電流（CA）方法對玻碳電極上金的成核機理進行了研究，研究表明金在玻碳電極上的成核方式為連續(xù)成核。
[Abstract]:During the preparation of inertial confinement fusion (ICF) targets, active metal uranium or its alloys are used as energy conversion materials, and a layer of simple gold with stable chemical properties is deposited as the supporting layer on the surface of the transition layer. Due to the strong activity of uranium substrate and the easy formation of oxide film on the surface, it is difficult to obtain the coating which meets the requirements by electrodeposition in the traditional aqueous solution system. Therefore, it is imperative to develop a new non-hydropower gold plating system. In this paper, Reline and Ethaline ionic liquids based on choline chloride were used as solvents, sodium chloraurate as main salt and dimethylhydantoin (DMH) as coordination agent. The effect of the composition of plating bath, temperature, current density and other process conditions on the properties of the coating. In Reline ionic liquids, the basic bath system was determined by orthogonal test, in which Au3 4g / L, DMH 45g / L, lithium chloride 15g / L, deposition potential -1.4V (vs. Pt). Through single factor test, it is found that the effect of current density and bath temperature on the coating appearance quality is greater than that of lithium chloride concentration. In the basic bath, a uniform and fine gold plating layer can be obtained by electrodeposition with nickel as the substrate, but the working current density is smaller and the current density range is narrow. This paper attempts to increase the current density by increasing the main salt concentration, bath temperature and adding diluent. The results show that the working current density is difficult to increase. In Ethaline ionic liquids, the basic bath system was preliminarily determined by a large number of experiments, and the composition was Au30g/L,DMH156g/L,Na2CO35g/L.. In the basic bath, the gold-plated gold layer can be obtained in the current density 2~10mA/cm2 range, but the gold coating obtained with the current of 6.5mA/cm2 has the best uniformity. When nickel is used as the substrate, the surface of the cathode is prone to a leakage zone, resulting in a black area, while when gold is used as the substrate, a uniform and meticulous gold-plated layer is easy to be obtained. With the increase of the main salt concentration, the working current density can be increased greatly. With the increase of the temperature, the coating appearance quality is improved, and the optimum bath temperature range is 90 ~ 100 鈩

本文編號：2376607