發(fā)布時(shí)間：2018-04-22 22:34

  本文選題：碳納米管 + Fe-N/CNTs復(fù)合材料��； 參考：《西南交通大學(xué)》2017年碩士論文

【摘要】：具備優(yōu)異的物理和化學(xué)性能碳納米管(carbonnanotubes,CNTs)自1991年被發(fā)現(xiàn)以來。就被發(fā)掘出了諸多優(yōu)點(diǎn),例如,耐熱性好,比表面積大,機(jī)械強(qiáng)度高等。碳納米管通過與磁性粒子的有機(jī)整合(在碳納米管表面包覆或管內(nèi)填充磁性納米粒子),可以同時(shí)綜合兩者的物理性質(zhì)和化學(xué)性質(zhì),使其復(fù)合產(chǎn)物在催化劑、磁存儲、生物醫(yī)學(xué)、吸波劑等領(lǐng)域具有廣闊的應(yīng)用前景。因此,相較于其他材料,碳納米管的復(fù)合材料的使用會使其具有出人意料的優(yōu)異性能。本論文旨在采用填充法,在一定溫度下制備出Fe-N/CNTs納米復(fù)合材料,研究不同氨氣流量對樣品組織、成分與性能的影響,并分析其制備形成機(jī)理,為開發(fā)新型磁性碳納米管的應(yīng)用方面提供試驗(yàn)與理論基礎(chǔ)。本論文在之前研究工作的基礎(chǔ)上,以平均直徑20～50納米的碳納米管(純度90%)為原料,使用Fe(N03)3的過飽和溶液并利用碳納米管的毛細(xì)作用制備了 Fe(N03)3-CNTs復(fù)合物。將該粉末經(jīng)過干燥后,在650℃不同氨氣流量(0.1～2m3/h)下進(jìn)行氣體氮化處理2h,并在無氨氣氛圍下進(jìn)行對比實(shí)驗(yàn),對其實(shí)驗(yàn)進(jìn)行初步探究。同時(shí)對不同工藝制備的樣品進(jìn)行顯微組織的觀察及物相結(jié)構(gòu)、磁學(xué)性能、吸波性能的測試與分析。研究結(jié)果表明,本論文利用填充法,通過碳納米管的毛細(xì)作用與不同的氨氣流量成功制備了具有填充型磁性碳納米管復(fù)合材料,磁性粒子主要包括γ'-Fe4N、ε-Fe3N、ξ-Fe2N以及及-Fe22O。在Fe-N//NTs復(fù)合材料的制備過程中,因?yàn)椴煌睔饬髁苛揩@得不同氮含量的Fe-N合金。在650℃滲氮時(shí),由于納米Fe203顆粒的出現(xiàn)以及氮勢與硝酸鐵濃度控制得當(dāng),使反應(yīng)偏離了理論上的共析轉(zhuǎn)變。在本論文Fe-N/CNTs復(fù)合材料的制備工藝中,650℃保溫2h且氨氣流量0.5m3/h時(shí)所得到的γ'-Fe4N/CNTs具有較高的飽和磁化強(qiáng)度(91.79emu/g)、矯頑力(219.350e)、磁學(xué)性能分布均勻和低頻段吸波性能潛力巨大(RL=-10.91dB)等最佳的綜合性能。在對比試驗(yàn)中,無氨氣的氛圍下Fe(N03)3/CNTs中Fe(N03)3受熱分解成α-Fe203后發(fā)生一系列轉(zhuǎn)變并通過Fe3O4生成γ-Fe203。γ-Fe203/CNTs 不僅具有良好的磁學(xué)性能(Ms=61.86emu/g、Hc=232.50e)而且在吸波性能方面也因其阻抗匹配更優(yōu)于Fe-N/CNTs復(fù)合材料也較為出眾,故具有更好的吸波性能(d=1.8mm,RL=-34.23dB,有效帶寬為1.2GHz)。Fe4N/CNTs復(fù)合材料的阻抗匹配還有所欠缺,故在吸波劑方面還需要進(jìn)一步研究與拓寬。
[Abstract]:Carbon nanotubes with excellent physical and chemical properties have been discovered since 1991. Many advantages have been discovered, such as good heat resistance, large specific surface area, high mechanical strength and so on. Through organic integration with magnetic particles (coating or filling the carbon nanotubes with magnetic nanoparticles), carbon nanotubes can combine the physical and chemical properties of the two products in catalyst, magnetic storage, biomedicine. Wave absorbers and other fields have a broad application prospects. Therefore, compared with other materials, the use of carbon nanotubes composites will make it have unexpected excellent performance. In this paper, Fe-N/CNTs nanocomposites were prepared by filling method at a certain temperature. The effects of different ammonia flow rates on the microstructure, composition and properties of the samples were studied, and the mechanism of their preparation was analyzed. It provides experimental and theoretical basis for the development of new magnetic carbon nanotubes. On the basis of previous research work, the Fe(N03)3-CNTs composites were prepared by using the supersaturated solution of Fe(N03)3 and the capillary action of carbon nanotubes (CNTs) with an average diameter of 20 ~ 50 nanometers (purity 90 kum). After drying, the powder was nitrided for 2 h at 650 鈩，

本文編號：1789261