SiCN前驱体陶瓷的制备及其吸波性能研究

发布时间：2018-03-03 22:18

本文选题：SiCN前驱体陶瓷　切入点：纳米氧化铁　出处：《山东大学》2015年硕士论文　论文类型：学位论文

【摘要】：电磁辐射污染的治理和雷达隐身技术的发展使得吸波材料的制备和应用成为人们研究的热点。由于传统型吸波材料尤其是铁氧体和传统陶瓷类吸波材料的密度相对较大,限制了其在该领域的进一步发展,因此相对轻质、导电性和介电性能较好的硅碳氮前驱体陶瓷在吸波材料中具有潜在的应用价值。SiCN前驱体陶瓷材料具有优异的导电性和介电性能,在此基础上在SiCN前驱体陶瓷中引入铁离子,可使其具有特别的磁性能。因此,本文以聚硅氮烷为前驱体、以过氧化二异丙苯为交联剂,利用前驱体热解法制备了SiCN前驱体陶瓷,分析了其在热解过程中基本结构的转化和组成,研究了材料的电性能、介电性能和微波吸收性能。另外,通过添加乙酰丙酮铁、铁、氧化铁和四氧化三铁四种不同的铁源,成功制备了SiCN(Fe)前驱体陶瓷,研究了产物的介电性能及磁性能,探讨了铁的加入对吸波性能的影响。通过对SiCN和SiCN(Fe)前驱体陶瓷制备及性能的研究,主要得出如下结论：分析了聚硅氮烷前驱体的交联热解过程,红外光谱分析发现在800℃时,样品已基本陶瓷化,且热重分析表明其陶瓷化程度在75%左右；光电子能谱分析结果表明,热解产物以Si、C、N的成键和游离C的形式存在,N有部分流失；XRD结果表明：该SiCN前驱体陶瓷在900℃-1350℃热解时具有无定型结构；微观结构分析表明随着热解温度的升高,样品的均一性提高,气孔率降低,1400℃及以上温度热处理时,SiCN前驱体陶瓷会由非晶相结构向晶体结构转变。研究了热解温度对SiCN前驱体陶瓷电性能及介电性能的影响,发现在不同温度处理的SiCN前驱体陶瓷的I-V关系基本为直线,且随着处理温度的增加(1000℃-1450℃),前驱体SiCN陶瓷的电阻率降低,电导率升高,介电常数升高,材料的介电性能有明显提高；同时探讨了样品厚度对SiCN前驱体陶瓷的介电性能的影响,结果表明：当样品厚度最大为4mm时,材料的介电性能最优,且当频率达到12.7GHz时,其介电损耗达到最大为3.1。研究了甲基丙烯酸对SiCN前驱体陶瓷的结构、含碳量及介电性能和吸波性能的影响。结果表明：当添加6wt%的甲基丙烯酸时样品的含碳量明显增加,介电常数明显增大,在12.7GHz处,样品6-MA的介质损耗达到最大为0.75,反射率达到-4.8dB,电磁衰减系数为240,该材料具有一定的吸波性能。将乙酰丙酮铁、铁、氧化铁和四氧化三铁四种铁源分别与聚硅氮烷复合制备了SiCN(Fe)前驱体陶瓷,研究了各个样品的结构、相组成及微波吸收性能。XRD结果表明,样品中均出现α-Fe和C两种晶体；从电磁性能分析可知,铁源的加入使得材料的介电常数和介电损耗明显增加,与其他铁源相比,Fe304的加入对材料的介电损耗和磁损耗的影响较大,且10GHz左右共振峰的出现使得两种损耗均达到最大值,其介电损耗值为2.1,磁损耗角正切值为0.5,这与极化机制的退出和转变有关。由于介电共振峰和磁共振峰的存在,在10GHz处加入Fe304的SiCN(Fe)前驱体陶瓷的反射率低于其它样品,为-4.7dB,其电磁衰减系数达到最大,为800。探讨了纳米氧化铁的加入量(6wt%,12wt%,15wt%,18wt%)对SiCN(Fe)前驱体陶瓷吸波性能的影响。结果表明当样品中加入18wt%的纳米氧化铁时,在10GHz处,材料的反射率R降到最低,电磁衰减系数“的值达到最大,其值分别为-11dB和325,吸波性能较好,能够满足微波吸收的要求。本论文制备的SiCN前驱体陶瓷和SiCN(Fe)前驱体陶瓷可作为微波吸收材料,具有着良好的潜在应用前景。
[Abstract]:The development of stealth technology, electromagnetic radiation pollution governance and the radar absorbing material preparation and application become the research hotspot. Because the traditional absorbing materials especially ferrite and traditional ceramic absorbing wave material density is relatively large, the limit in the field of further development, so relatively light, the conductivity and dielectric properties of silicon carbonitride ceramic precursor in microwave absorbing material has the application value of.SiCN precursor ceramic material potential has excellent conductivity and dielectric properties, on the basis of the precursor of SiCN ceramic by iron ion, which can have their special magnetic properties. Therefore in this paper, polysilazane precursor with two peroxide cumene as crosslinking agent, the precursor of SiCN ceramic prepared by precursor pyrolysis method, analyzes the basic structure and transformation in the pyrolysis process, the material is studied. Electrical properties, dielectric properties and microwave absorption power. In addition, by adding acetylacetone iron, iron, iron oxide and iron oxide in four different iron sources, SiCN was successfully prepared (Fe) precursors of ceramics, dielectric properties and magnetic properties of the product, discusses the iron addition effect on absorbing properties. Based on the SiCN and SiCN (Fe) of the ceramic precursor preparation and properties, the main conclusions are as follows: the analysis of the process of crosslinking pyrolysis of polysilazane precursor, infrared spectroscopy analysis showed that at 800 DEG C, the sample has been basically ceramic, and thermogravimetric analysis showed that the degree in ceramics about 75%; photoelectron spectroscopy. The results showed that the pyrolysis products are mainly Si, C, C are bonded and free form of N, N is part of the loss; XRD results showed that the precursor of SiCN ceramics at 900 DEG -1350 DEG pyrolysis with amorphous structure; microstructure analysis shows that with the The increase of pyrolysis temperature, homogeneity of the samples increased, the porosity decreased and the temperature above 1400 DEG C and heat treatment, SiCN ceramic precursor from amorphous phase structure to change the crystal structure. The effect of pyrolysis temperature on the precursor of SiCN ceramic dielectric properties and dielectric properties of SiCN ceramic precursor, found in different the temperature of processing I-V relationship as a straight line, and with the increase of treatment temperature (1000 DEG -1450 DEG), resistivity precursor of SiCN ceramic decreased, the conductivity increased, higher dielectric constant, dielectric properties of materials are improved obviously; and discuss the influence of sample thickness on the dielectric properties of SiCN ceramic precursor the results show that when the thickness of the sample was 4mm, the optimal dielectric properties of materials, and when the frequency reaches 12.7GHz, the dielectric loss reached a maximum of 3.1. to study the structure of methacrylic acid on SiCN ceramic precursor, carbon Effect of amount and dielectric properties and microwave absorbing properties. The results show that when the carbon content of methacrylic acid 6wt% added sample was significantly increased, the dielectric constant was increased at 12.7GHz, the dielectric loss of the sample 6-MA reached a maximum of 0.75, the reflectivity of -4.8dB, electromagnetic attenuation coefficient is 240, the material has the microwave absorbing properties. The ferric acetylacetonate, iron oxide and iron oxide, four iron source and polysilazane compound was prepared by SiCN (Fe) ceramic precursor, studied the structure of each sample, phase composition and microwave absorption properties of.XRD showed that the alpha -Fe and C two kinds of crystal appeared in the sample; from the analysis of the electromagnetic properties of the iron source due to the dielectric constant and the dielectric loss was obviously increased, compared with other iron sources, effects of Fe304 addition on the dielectric loss and magnetic loss is large, and the resonance peak is about 10GHz Now the two losses reached the maximum, the dielectric loss value is 2.1, the magnetic loss tangent was 0.5, and the polarization mechanism of exit and transformation. Because the dielectric resonance and magnetic resonance peak, adding Fe304 at 10GHz SiCN (Fe) ceramic precursor reflectivity below the other sample is -4.7dB, the electromagnetic attenuation coefficient reached the maximum amount of iron oxide nanoparticles was 800. (6wt%, 12wt%, 15wt%, 18wt%) of SiCN (Fe) precursor ceramic absorbing properties was studied. The results show that when adding iron oxide nano 18wt% samples, at 10GHz, reflectivity of R materials to a minimum, "the electromagnetic attenuation coefficient reaches the maximum value, the value of -11dB and 325 respectively, the absorbing performance is good, can satisfy the requirements of microwave absorption. This paper prepared precursor of SiCN ceramic and SiCN ceramic precursor (Fe) can be used as microwave absorbing materials, has a good Potential application prospects.

【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ174.1

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