本文選題：納米鎳粉　切入點(diǎn)：電沉積　出處：《大連理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：自20世紀(jì)80年代以來,納米技術(shù)就被預(yù)言是21世紀(jì)的科學(xué)前沿和主導(dǎo)科學(xué)。磁性鎳納米粒子由于具有獨(dú)特的物理、化學(xué)性質(zhì),在催化劑、磁性材料、導(dǎo)電漿料、納米涂層材料、電池材料以及硬質(zhì)合金粘接劑等許多領(lǐng)域有廣泛的應(yīng)用前景,引起了科學(xué)家們的高度關(guān)注。液相法制備金屬納米粉,由于操作簡單、產(chǎn)率高、產(chǎn)品尺寸和形貌可控制等優(yōu)勢,是實(shí)驗(yàn)室和工業(yè)生產(chǎn)廣泛采用的合成方法。目前,液相法制備納米鎳粉(電解法除外,一般在水溶液中進(jìn)行)一般使用還原劑水合肼、NaBH4/KBH4,或者使用有機(jī)醇、亞磷酸鈉等。前三種試劑有較強(qiáng)的毒性,后兩種要么反應(yīng)速率緩慢,要么引入了雜質(zhì)得不到純凈的納米鎳粉。從還原性有機(jī)溶劑體系電沉積制備納米金屬粉末,既無需使用還原劑,且有機(jī)溶劑還可以阻止金屬粉末氧化和團(tuán)聚發(fā)生。本論文在不加還原劑的條件下,以鎳鹽的乙醇溶液為電解質(zhì),電沉積鎳粉,并通過單因子變量實(shí)驗(yàn)探究了鎳鹽濃度、脈沖電壓以及表面活性劑種類和濃度對鎳粉結(jié)構(gòu)、形貌和磁學(xué)性能的影響,通過X射線衍射、透射電鏡、掃描電鏡、振動樣品磁強(qiáng)計(jì)和傅里葉紅外光譜儀表征,得出以下結(jié)論：所制備的鎳粉均具有面心立方結(jié)構(gòu),鎳粉微觀呈樹枝晶狀,平均粒徑在100nm以下,鎳粉表現(xiàn)鐵磁性,飽和磁化強(qiáng)度大約在30-45emu/g之間,矯頑力大約在150-3500e之間。1)隨著氯化鎳乙醇溶液的初始濃度升高,鎳粉的晶粒尺寸逐漸增大；樹枝化更加明顯；飽和磁化強(qiáng)度緩慢增加,剩磁比明顯減小,矯頑力先減小后增加。2)隨著電壓的升高,鎳粉的晶粒尺寸逐漸減��；樹枝晶形貌沒有明顯變化；飽和磁化強(qiáng)度呈減小趨勢,剩余磁化強(qiáng)度、矯頑力和剩磁比的變化趨勢一致,均為從最小值激增到最大值,然后驟減,最后平穩(wěn)緩慢增加。3)電解液添加聚乙烯吡咯烷酮(PVP)和十二烷基硫酸鈉(SDS)后,鎳粉的相結(jié)構(gòu)、平均晶粒尺寸、晶粒取向度相似,后者的磁性略低于前者；改變陰離子表面活性劑濃度時(shí),隨著SDS濃度的升高,鎳粉的晶粒尺寸在25±5nm范圍內(nèi)起伏變化；樹枝晶分支數(shù)量減小,長度變短。SDS濃度11.67mg/L時(shí),飽和磁化強(qiáng)度、剩余磁化強(qiáng)度和矯頑力隨SDS濃度增大,緩慢減��；SDS濃度11.67mg/L時(shí),飽和磁化強(qiáng)度、剩余磁化強(qiáng)度和矯頑力隨SDS濃度增大,逐漸增大。剩磁比總體呈上升趨勢。4)與水溶液電沉積不同的是,電沉積過程中乙醇分子參與了陽極放電過程,但并未進(jìn)一步被氧化形成醛或者酸,且乙醇起到了阻礙鎳粒子氧化的作用。
[Abstract]:Since 1980s, nanotechnology has been predicted to be the scientific frontier and leading science of 21th century. Magnetic nickel nanoparticles have unique physical and chemical properties in catalysts, magnetic materials, conductive pastes, nano-coated materials, Battery materials and cemented carbide adhesives have been widely used in many fields, which have attracted great attention of scientists. Due to the advantages of simple operation, high yield, controllable size and shape of products, the preparation of metal nano-powders by liquid phase method has many advantages, such as simple operation, high yield, and the size and morphology of products can be controlled. It is a widely used synthetic method in laboratory and industrial production. At present, the liquid phase method is used to prepare nano-nickel powder (except electrolysis, usually in aqueous solution), generally using the reductant hydrazine hydrate, NaBH4 / KBH4, or using organic alcohol, Sodium phosphite and so on. The first three reagents have strong toxicity, and the latter two are either slow in reaction rate or have introduced impurity not pure nano-nickel powder. The nanometer metal powder is prepared by electrodeposition from reductive organic solvent system. The oxidation and agglomeration of metal powder can be prevented by organic solvent without reducing agent. In this paper, nickel powder was electrodeposited with ethanol solution of nickel salt as electrolyte. The effects of nickel salt concentration, pulse voltage, type and concentration of surfactants on the structure, morphology and magnetic properties of nickel powder were investigated by single factor variable experiments. The results were analyzed by X-ray diffraction, transmission electron microscope, scanning electron microscope, X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). Vibration sample magnetometer and Fourier transform infrared spectroscopy (FTIR) showed that the nickel powder had a face-centered cubic structure, the nickel powder was dendritic, the average particle size was below 100 nm, and the nickel powder was ferromagnetic. The saturation magnetization is about 30-45 emu / g, and the coercivity is about 150-3500e.) with the increase of the initial concentration of nickel chloride solution, the grain size of nickel powder increases gradually, the dendrization becomes more obvious, and the saturation magnetization increases slowly. With the increase of voltage, the grain size of nickel powder decreases gradually, the morphology of dendrite does not change obviously, the saturation magnetization decreases, and the residual magnetization decreases. The change trend of coercivity and remanent magnetic ratio is consistent, which is the phase structure of nickel powder after increasing from the minimum value to the maximum value, then to the maximum value, then to the sharp decrease, and finally to increasing steadily and slowly. 3) after adding polyvinylpyrrolidone (PVP) and sodium 12 alkyl sulfate (SDSs) into the electrolyte, The average grain size and orientation degree of nickel powder were similar, and the magnetic properties of the latter were slightly lower than those of the former. When the concentration of anionic surfactant was changed, the grain size of nickel powder fluctuated in the range of 25 鹵5 nm with the increase of SDS concentration, and the number of dendritic branches decreased. The saturation magnetization, remanent magnetization and coercivity increased with the increase of SDS concentration when the length became shorter. The saturation magnetization, residual magnetization and coercivity increased with the increase of SDS concentration. The remanent magnetic ratio (R) showed an increasing trend. 4) different from the electrodeposition of aqueous solution, ethanol molecules participated in the anodic discharge process, but were not further oxidized to aldehydes or acids. Ethanol also acts as an obstacle to the oxidation of nickel particles.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB383.1;TQ153.12

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本文編號：1623511