【摘要】：金屬釹(Nd)是較重要的稀土金屬之一,因為其獨特的4f電子層結(jié)構(gòu),所以一些Nd及含Nd合金具備了特殊的光、電、磁和催化性能,在現(xiàn)代工業(yè)中應(yīng)用極其廣泛,其主要應(yīng)用領(lǐng)域有永磁體材料、高級金屬合金以及添加劑等等。然而在實際應(yīng)用中,往往需要對Nd及其合金進行表面處理,以提高其耐蝕性能。由于Nd的活性高,表面處理的難度極大,因此尋找適合金屬Nd及其合金特點的表面處理新介質(zhì),并開展相關(guān)的應(yīng)用及機理的研究,是表面科學(xué)與技術(shù)領(lǐng)域中重要的課題。離子液體是一種新型溶液,是除水和有機溶劑之外的第三大溶劑,在活性金屬的表面工程領(lǐng)域中具有獨特的應(yīng)用前景。本文主要研究了Nd在2：1酸性AlCl3-氯化1-甲基-3-乙基咪唑(AlCl3-EMIC)、0.8：1堿性AlCl3-EMIC以及1-丁基-1-甲基吡咯烷雙(三氟甲磺酰)亞胺鹽([BMP]Tf2N)離子液體中的陽極行為。采用循環(huán)伏安法測定了三種離子液體的電位窗；通過線性伏安掃描、恒電流極化以及恒電位極化研究了Nd在離子液體中陽極溶解,利用恒電流溶解計算了Nd的溶解價態(tài)；最后采用SEM考察了恒電流溶解之后Nd的表面形貌,并通過EDS和原位Raman進行Nd表面成分的分析。本文的研究結(jié)果表明,在2：1酸性AlCl3-EMIC中,當(dāng)陽極電流密度≥5mA/cm2時,在Nd和離子液體的界面會形成粘性膜。粘性膜的產(chǎn)生是由于高粘度的溶解產(chǎn)物Nd(Ⅲ)在Nd和離子液體界面聚集的結(jié)果。粘性膜的產(chǎn)生有著“鈍化—活化”的作用,在該作用下,Nd基體發(fā)生均勻溶解,表面的氧化膜被徹底去除,并且溶解后的Nd基體表面非常均勻平滑。當(dāng)陽極電流密度 2 mA/cm2時,不形成粘性膜。因為沒有粘性膜的“鈍化—活化”作用,Nd基體發(fā)生局部溶解,在其表面形成許多點蝕坑,表面的氧化膜不能被徹底去除。在0.8：1堿性AlCl3-EMIC和[BMP]Tf2N離子液體中,Nd表面氧化膜對陽極溶解有著很大的影響,只有在一定的陽極電位(0V和1.4 V vs. Pt)下,氧化膜才會發(fā)生破壞,隨后Nd發(fā)生溶解；Nd的溶解產(chǎn)物分別為[NdCl6]3-和[Nd(Tf2N)x](x-3)-可溶性絡(luò)合離子；Nd恒電流溶解的過程中,在較低的電流密度下(分別為0.2 mA/cm2和0.1 mA/cm2),表面氧化膜在極少區(qū)域破壞,Nd發(fā)生局部溶解；在較高的電流密度下(分別為2 mA/cm2和1 mA/cm2),氧化膜完全破壞,Nd發(fā)生均勻溶解。但是由于在這兩種離子液體中,Nd陽極溶解時沒有粘性膜的產(chǎn)生,所以Nd溶解后的表面并不均勻平滑。
[Abstract]:Neodymium (Nd) is one of the most important rare earth metals. Because of its unique 4f electronic layer structure, some Nd and Nd containing alloys have special optical, electrical, magnetic and catalytic properties and are widely used in modern industry. Its main applications are permanent magnet materials, high-grade metal alloys and additives and so on. However, in practical application, surface treatment of Nd and its alloys is often needed to improve their corrosion resistance. Because of the high activity of Nd and the difficulty of surface treatment, it is an important subject in the field of surface science and technology to find a new surface treatment medium suitable for the characteristics of metal Nd and its alloys, and to study its application and mechanism. Ionic liquid is a new kind of solution, which is the third largest solvent besides water and organic solvent. It has a unique application prospect in the field of surface engineering of active metals. The anodic behavior of Nd in 1methyl-3-ethylimidazole (AlCl3-EMIC) and 1-Ding Ji -1-methylpyrrolidine bis (trifluoromethylsulfonyl) imide ([BMP] Tf2N) ionic liquids chlorided by 2:1 acidic AlCl3- has been studied in this paper. The potential windows of three kinds of ionic liquids were determined by cyclic voltammetry, the anodic dissolution of Nd in ionic liquids was studied by linear voltammetry, constant current polarization and constant potential polarization, and the dissolution valence of Nd was calculated by constant current dissolution. Finally, the surface morphology of Nd after constant current dissolution was investigated by SEM, and the surface composition of Nd was analyzed by EDS and in situ Raman. The results show that in 2:1 acidic AlCl3-EMIC, when the anode current density is greater than or equal to 5mA/cm2, a viscous film will be formed at the interface between Nd and ionic liquids. The formation of viscous film is due to the aggregation of high viscosity dissolved product Nd (鈪，

本文編號：2251496