發(fā)布時(shí)間：2018-11-01 13:08

【摘要】：金屬鈦具有優(yōu)異的耐蝕性、比強(qiáng)度高、質(zhì)輕和良好的生物相容性等特點(diǎn),被美譽(yù)為“太空金屬”,廣泛用于航空航天、石油化工、能源、生物醫(yī)療等領(lǐng)域。目前,工業(yè)上生產(chǎn)鈦的方法主要為Kroll法,但存在工藝流程長,能耗大,環(huán)境污染嚴(yán)重等問題。而熔鹽電解法存在能耗大、設(shè)備腐蝕嚴(yán)重、電流效率低等問題,難以實(shí)現(xiàn)工業(yè)化。離子液體具有極低的蒸汽壓、較寬的電化學(xué)窗口、室溫下呈液態(tài)、可設(shè)計(jì)性等特點(diǎn),它的出現(xiàn)為低溫電沉積鈦開辟了新的道路。目前,用于電沉積金屬鈦的離子液體多為咪唑類離子液體,然而咪唑類離子液體的電化學(xué)窗口較窄,并不適用于金屬鈦的沉積。本文以上述背景出發(fā),篩選出兩種適合沉積鈦的離子液體,并且系統(tǒng)的研究了離子液體中金屬鈦的電沉積過程。本論文的主要研究?jī)?nèi)容以及成果具體如下:(1)合成了[BisoMPyrr]NTf_2和[N1,2,2,4]NTf_2兩種離子液體,并采用1H NMR、13C NMR以及質(zhì)譜對(duì)其結(jié)構(gòu)進(jìn)行表征,證明為目標(biāo)離子液體,通過對(duì)雜質(zhì)進(jìn)行檢測(cè),離子液體純度很高,均能達(dá)到電化學(xué)實(shí)驗(yàn)的要求。(2)分別測(cè)定了兩種離子液體電導(dǎo)率,其電導(dǎo)率都隨著溫度的升高而升高。在兩種離子液體中分別加入TiCl_4之后,電導(dǎo)率有所降低。并且電導(dǎo)率對(duì)數(shù)lnκ與溫度的倒數(shù)l/T呈線性關(guān)系,符合Arrhenius方程。(3)采用[BisoMPyrr]NTf_2-TiCl_4體系進(jìn)行電沉積金屬鈦的研究,循環(huán)伏安測(cè)試表明陰極上鈦的還原至少為兩步。XRD及XPS的結(jié)果表明,沉積層中鈦主要是以TiCl_3和TiO_2的形式存在,生成的TiCl_3附著在電極表面阻礙進(jìn)一步還原,沉積得到的少量Ti在空氣中被氧化成TiO_2。紫外吸收結(jié)果表明沉積后體系中已檢測(cè)不到Ti(Ⅳ),而同時(shí)也沒有獲得到Ti(Ⅱ)的吸收峰。(4)以[N1,2,2,4]NTf_2-TiCl_4體系進(jìn)行電沉積鈦的研究,循環(huán)伏安測(cè)試表明鈦的還原為三步電子轉(zhuǎn)移。沉積層表面形貌不均勻,晶體的形狀為不規(guī)則、獨(dú)立的顆粒狀。能譜顯示基底銀含量太高,鈦含量比較低。XRD結(jié)果表明,在沉積層中有TiO_2和金屬Ti的存在。紫外吸收結(jié)果表明沉積后體系中檢測(cè)不到Ti(Ⅳ),也沒有Ti(Ⅱ)的吸收峰。
[Abstract]:Titanium has excellent corrosion resistance, high specific strength, light weight and good biocompatibility. It is widely used in aerospace, petrochemical, energy, biomedical and other fields. At present, the main method of titanium production in industry is Kroll process, but there are many problems, such as long technological process, high energy consumption, serious environmental pollution and so on. However, molten salt electrolysis has many problems, such as high energy consumption, serious equipment corrosion and low current efficiency, so it is difficult to realize industrialization. Ionic liquids have the characteristics of very low vapor pressure, wide electrochemical window, liquid state at room temperature and designability. The appearance of ionic liquids opens a new way for low temperature electrodeposition of titanium. At present, the ionic liquids used in electrodeposition of titanium metal are mostly imidazole ionic liquids, however, the electrochemical window of imidazole ionic liquids is narrow, so it is not suitable for the deposition of titanium metal. Based on the above background, two kinds of ionic liquids suitable for titanium deposition were selected, and the electrodeposition process of titanium in ionic liquids was studied systematically. The main contents and achievements of this thesis are as follows: (1) two kinds of ionic liquids, [BisoMPyrr] NTf_2 and [N1O2O2O4] NTf_2, were synthesized, and their structures were characterized by 1H NMR,13C NMR and mass spectrometry. It is proved that the ionic liquid is the target ionic liquid, and the purity of the ionic liquid is very high, which can meet the requirements of electrochemical experiment. (2) the conductivity of two kinds of ionic liquids is measured, and the conductivity increases with the increase of temperature. After the addition of TiCl_4 into the two ionic liquids, the conductivity decreased. And the logarithmic ln 魏 has a linear relationship with the reciprocal 1 / T of temperature, which accords with the Arrhenius equation. (3) the electrodeposition of titanium metal is studied by [BisoMPyrr] NTf_2-TiCl_4 system. Cyclic voltammetry showed that the reduction of titanium on the cathode was at least two steps. The results of XRD and XPS showed that the titanium in the deposited layer mainly existed in the form of TiCl_3 and TiO_2, and the formed TiCl_3 adhered to the electrode surface to prevent further reduction. A small amount of Ti deposited in air was oxidized to TiO_2. The ultraviolet absorption results show that Ti (鈪，

本文編號(hào)：2304012