本文關(guān)鍵詞： TiC納米材料 SiC/SiO2復(fù)合材料 介電性能 微波吸收 損耗機(jī)制　出處：《西北工業(yè)大學(xué)》2015年博士論文　論文類(lèi)型：學(xué)位論文

【摘要】：隨著電子設(shè)備和無(wú)線(xiàn)通訊的快速發(fā)展，電磁干擾和輻射污染問(wèn)題已經(jīng)嚴(yán)重影響了人們生活和國(guó)家安全，尤其是雷達(dá)波隱身技術(shù)已經(jīng)成為軍事戰(zhàn)略的制高點(diǎn)之一。目前，電磁波吸收材料的研究依然立足于傳統(tǒng)的吸波材料，對(duì)于新型吸波材料的研究開(kāi)發(fā)明顯不足，特別是高溫和高頻段的微波吸收材料。因此，研究新型微波材料不僅對(duì)豐富和擴(kuò)大吸收材料的種類(lèi)和應(yīng)用領(lǐng)域具有現(xiàn)實(shí)意義，還具有較高的理論價(jià)值。 基于多重微波損耗機(jī)制，納米吸波材料顯示出優(yōu)良的微波吸收性能。作為典型的無(wú)氧陶瓷，TiC和SiC具有高熔點(diǎn)、低密度、良好導(dǎo)電和導(dǎo)熱性、優(yōu)異的環(huán)境穩(wěn)定性等特性，結(jié)合這些優(yōu)異的特性和納米結(jié)構(gòu)使得TiC和SiC納米材料成為潛在的微波吸收材料。本論文以納米材料的制備和應(yīng)用為背景，采用氯氣輔助碳熱還原反應(yīng)法、熱化學(xué)反應(yīng)法和納米鑄造法，分別系統(tǒng)地研究了TiC納米線(xiàn)、TiC納米顆粒/Ti和有序內(nèi)部填充結(jié)構(gòu)SiC/SiO2納米材料的可控制備及其微觀結(jié)構(gòu)，并分析了它們?cè)赬波段(8.2~12.4GHz)的室溫和高溫微波吸收性能和相應(yīng)的損耗機(jī)理。主要研究?jī)?nèi)容與結(jié)果如下： (1)研究了以氯氣輔助碳熱還原法制備TiC納米線(xiàn)。研究表明，以Ni(NO3)2·6H2O為催化劑、NaCl為輔助劑、蔗糖為碳源和TiO2納米粉為T(mén)i源，成功制備了面心立方結(jié)構(gòu)的單晶TiC納米線(xiàn)，其長(zhǎng)徑比和比表面積分別為80~100和186.7m2/g。TiC納米線(xiàn)的初始生長(zhǎng)機(jī)理為VSL機(jī)理，并給出了可能的化學(xué)反應(yīng)方程式。 (2)以丙酮為碳源，研究了在金屬Ti顆粒表面原位生長(zhǎng)TiC納米顆粒。結(jié)果表明，當(dāng)載氣Ar流量為50ml/min，通過(guò)鼓泡方式攜帶0oC的丙酮進(jìn)入反應(yīng)腔體，反應(yīng)溫度和反應(yīng)時(shí)間分別為800°C和2.0h時(shí)，大小約為300nm的TiC納米顆粒均勻且稠密地分布在金屬Ti顆粒表面，其晶體結(jié)構(gòu)為多晶面心立方結(jié)構(gòu)，晶粒大小約為8.0nm。熱力學(xué)計(jì)算表明，丙酮在高溫下熱解產(chǎn)生的小分子氣體CHx優(yōu)先與Ti發(fā)生熱化學(xué)反應(yīng)得到TiC。 (3)以聚碳硅烷(PCS)和有序介孔氧化硅SBA-15為前驅(qū)體和硬模板，采用納米鑄造和冷壓成型工藝制備有序內(nèi)部填充結(jié)構(gòu)SiC/SiO2塊體陶瓷復(fù)合材料。結(jié)果表明，PCS轉(zhuǎn)化生成的SiC納米顆粒幾乎完全填滿(mǎn)了有序介孔SBA-15的納米孔道。復(fù)合材料的結(jié)晶度隨著反應(yīng)溫度的升高而增大，其晶型為β-SiC。在反應(yīng)溫度不高于1400oC時(shí)，SiC/SiO2復(fù)合材料不僅能夠保持有序內(nèi)部填充結(jié)構(gòu)，而且具有一定的機(jī)械強(qiáng)度。 (4)詳細(xì)表征了TiC納米線(xiàn)、TiC納米顆粒/Ti和有序填充結(jié)構(gòu)SiC作為吸波劑與石蠟或SiO2的復(fù)合材料在X波段的常溫和高溫微波吸收性能。結(jié)果表明，在常溫環(huán)境中，摻比量為30wt%的TiC納米線(xiàn)與石蠟混合材料具有最強(qiáng)的吸收強(qiáng)度：厚度為1.7mm時(shí)，其最小反射損耗約為-51.0dB；而1400oC制備的SiC/SiO2復(fù)合材料顯示出最大的吸收寬度：厚度為3.0mm時(shí)，有效吸收寬度(RL-10dB)覆蓋整個(gè)X波段。在高溫環(huán)境中，摻比量為7.5wt%的TiC納米線(xiàn)/SiO2復(fù)合材料在300oC具有最強(qiáng)的吸收強(qiáng)度：厚度為3.0mm時(shí)，最小反射損耗數(shù)值為-61.0dB；而1300oC制備的SiC/SiO2復(fù)合材料具有優(yōu)異的吸收寬度，在25~500oC范圍內(nèi)始終存在一個(gè)匹配的厚度，使其有效吸收寬度(RL-10dB)為整個(gè)X波段。 (5)研究了上述三種材料的微波損耗機(jī)理，結(jié)合四分之一波長(zhǎng)定律和阻抗匹配定律分析了單層吸收體的微波吸收性能。結(jié)果表明，三種材料優(yōu)異的吸收性能主要源于多重?fù)p耗機(jī)制：長(zhǎng)徑比較大的TiC納米線(xiàn)分散在透波基體中容易形成復(fù)雜網(wǎng)狀電子導(dǎo)電結(jié)構(gòu)，進(jìn)而導(dǎo)致較大的導(dǎo)電損耗；TiC納米顆粒/Ti復(fù)合材料具有異質(zhì)材料微結(jié)構(gòu)，其電磁損耗以界面損耗和介電弛豫損耗為主；有序內(nèi)部填充結(jié)構(gòu)SiC/SiO2復(fù)合材料使電磁波經(jīng)過(guò)有序結(jié)構(gòu)多重反射和網(wǎng)狀導(dǎo)電結(jié)構(gòu)而損耗。單層吸收材料具有優(yōu)異的微波吸收性能，主要?dú)w因于其幾何厚度遵循干涉相消原理和電磁參數(shù)滿(mǎn)足阻抗匹配，，這為設(shè)計(jì)單層吸收體提供了依據(jù)。
[Abstract]:With the rapid development of electronic devices and wireless communication, electromagnetic interference and radiation pollution has seriously affected people's life and national security, especially the radar stealth technology has become one of the commanding heights of military strategy. At present, the research of electromagnetic wave absorbing materials is still based on the traditional absorbing materials, absorbing materials research for new is obviously insufficient, especially in high temperature and high frequency microwave absorbing materials. Therefore, the research of new microwave materials not only to enrich and expand the absorption type and application field of materials is of practical significance, theoretical value is higher.
Multiple microwave loss mechanism based on nano absorbing materials exhibit excellent microwave absorption properties. As a typical anaerobic ceramic, TiC and SiC have high melting point, low density, good electrical and thermal conductivity, excellent environmental stability and other characteristics, combined with the excellent properties and nano structure makes the TiC and SiC nano materials become absorbed the potential of microwave materials. In this paper, the preparation of nano materials and the application background of reduction method using chlorine assisted carbothermal thermochemical reaction method and nano casting method were systematically studied TiC nanowires, controllable preparation and microstructure of TiC /Ti nanoparticles and ordered nano materials filled with structure of SiC/SiO2. And analyzes them in the X band (8.2~12.4GHz) performance and the corresponding loss mechanism of microwave absorption at room temperature and high temperature. The main research contents and results are as follows:
(1) study on the preparation of TiC nanowires by chlorine assisted carbothermal reduction. The results show that the Ni (NO3) 2 - 6H2O as catalyst, NaCl as auxiliary agent, sucrose as carbon source and TiO2 nanoparticles as Ti source, single crystalline TiC nanowires with fcc structure were successfully prepared, its long and the initial diameter ratio were 80~100 and 186.7m2/g.TiC nanowires than the surface area of the growth mechanism of VSL mechanism, and gives the possible chemical reaction equation.
(2) using acetone as carbon source on the growth of TiC nanoparticles on the surfaces of metal Ti particles. The results show that when the flow rate of the carrier gas Ar 50ml/min, carrying 0oC acetone by bubbling way into the reaction chamber, reaction temperature and reaction time were 800 ~ C and 2.0h, the size is about on the surface Ti TiC metal particle distribution of 300nm particles is uniform and dense, the crystal structure of polycrystalline face centered cubic structure, the grain size is about 8.0nm. thermodynamic calculation indicates that the gas molecules CHx acetone produced by high temperature pyrolysis of the priority and the chemical reactions taking place in TiC. Ti
(3) using polycarbosilane (PCS) and ordered mesoporous silica SBA-15 as precursor and hard template, using nano casting and cold pressing process for preparing ordered internal packing structure of SiC/SiO2 bulk ceramic composite materials. The results showed that SiC nanoparticles PCS transformed almost completely filled with ordered mesoporous SBA-15 the nano pores. The degree of crystallinity of the composites increases with the increase of the reaction temperature, the crystal type of beta -SiC. is higher than that of 1400oC in the reaction temperature, SiC/SiO2 composite materials can not only maintain an orderly internal filling structure, but also has a certain mechanical strength.
(4) the detailed characterization of TiC nanowires, TiC nanoparticles and /Ti ordered structure SiC as absorbing composite filling agent and paraffin or SiO2 wave absorption properties in the X band microwave at room temperature and high temperature. The results showed that at room temperature, the proportion of TiC doped 30wt% nanowires with paraffin mixed material with absorption intensity the strongest: the thickness is 1.7mm, the minimum reflection loss is about -51.0dB; and the SiC/SiO2 composite materials prepared by 1400oC showed the absorption maximum width: thickness of 3.0mm, the effective width of absorption (RL-10dB) covering the entire X band. In a high temperature environment, mixed proportion of TiC nanowires of 7.5wt% composites with /SiO2 the strongest absorption intensity in 300oC: the thickness of 3.0mm, numerical minimum reflection loss is -61.0dB; and the SiC/SiO2 composite materials prepared by 1300oC have excellent absorption width in the range of 25~500oC, there is always a match The thickness of its effective absorption width (RL-10dB) is the whole X band.
(5) to study the microwave loss mechanism of these three kinds of materials, combined with 1/4 wavelength law and impedance matching law of microwave absorbing properties of single-layer absorber. The results showed that three kinds of materials with excellent absorption performance is mainly due to the multiple loss mechanism: TiC nanowires with high aspect ratio dispersed in the matrix to form transparent conductive structure of complex network electronics, which led to the loss of conductivity; TiC nano particles /Ti composite materials with microstructure of heterogeneous materials, the electromagnetic loss to interface loss and dielectric relaxation loss; ordered structure of SiC/SiO2 composite filled with electromagnetic wave through the ordered structure of multiple reflection and mesh structure and conductive loss. Single layer absorbing materials with excellent microwave absorption properties, mainly due to the geometric thickness following destructive interference and electromagnetic parameters meet the principle of impedance matching for the design The monolayer absorbers provide the basis.

【學(xué)位授予單位】：西北工業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TB383.1;TB34

【參考文獻(xiàn)】

相關(guān)期刊論文 前6條

1 趙東林,周萬(wàn)城;結(jié)構(gòu)吸波材料及其結(jié)構(gòu)型式設(shè)計(jì)[J];兵器材料科學(xué)與工程;1997年06期

2 翟青霞;黃英;苗璐;陳穎;;樹(shù)脂基復(fù)合吸波材料在航空、航天中的應(yīng)用[J];玻璃鋼/復(fù)合材料;2009年06期

3 李南;;外形設(shè)計(jì)對(duì)飛機(jī)隱身性能影響分析[J];電子工程師;2007年12期

4 楊曉蓉,楊立明,戴國(guó)憲;從F-117A看雷達(dá)截面外形隱身技術(shù)[J];光電技術(shù)應(yīng)用;2004年01期

5 秦潤(rùn)華;;納米吸波材料的物理實(shí)質(zhì)及研究進(jìn)展[J];紅外;2006年08期

6 伊翠云;;納米吸波材料的研究現(xiàn)狀與發(fā)展趨勢(shì)[J];纖維復(fù)合材料;2014年01期

相關(guān)博士學(xué)位論文 前3條

1 劉旭光;異形截面碳化硅纖維制備及其吸波性能[D];國(guó)防科學(xué)技術(shù)大學(xué);2010年

2 黃云霞;微波吸收劑的制備及性能研究[D];西安電子科技大學(xué);2009年

3 周敏;二氧化錳納米結(jié)構(gòu)的制備與吸波性能研究[D];蘭州大學(xué);2012年

本文編號(hào)：1524363