碳化硅纳米颗粒增强环氧树脂

以糠醇为碳源,正硅酸乙酯为硅源,含氢硅油为结构助剂,通过碳热还原的方法制备出碳化硅纳米颗粒,采用XRD、TEM、DLS对样品进行表征。结果表明,所得碳化硅纳米颗粒尺度分布在10～50 nm,其增强的环氧树脂,拉伸强度和压缩强度均有明显提高。     

正交优化纳米碳化硅粉的制备工艺参数

实验选用无水乙醇为液相介质,聚乙烯吡咯烷酮(PVP)作为修饰剂,采用高能球磨法,成功制备出分散良好的纳米碳化硅粉.通过正交实验,分析了球磨时间、碳化硅颗粒的加入量、碳化硅与修饰剂的质量比和转速4个工艺参数对纳米碳化硅粉的产率、产量和粉体的特征粒径D50的影响.结果表明在本实验条件下,制备纳米碳化硅粉的最佳工艺参数为:时间15 h,碳化硅的加入量30 g,碳化硅与修饰剂的质量比2∶1,转速300 r/min.     

溶胶-凝胶法制备纳米碳化硅粉末的研究

以工业硅溶胶和炭黑为主要原料，采用溶胶一凝胶法和碳热还原法制备了纳米碳化硅粉末，研究了原料组成和制备工艺对超细粉末质量的影响。结果表明：该方法可直接制备纯度较高，颗粒直径分布范围小，粒径在一定范围内可控制的纳米碳化硅粉末。     

通过SiC纳米颗粒的原位合成制备氧化铝/碳化硅复合材料

通过一种包含SiC纳米微粒原位合成的新技术制备氧化铝/碳化硅复合材料。在水悬浮液中制备氧化铝粉末和碳化硅前体混合物。通过冷冻破碎和氩气中1 750℃、4h的无压烧结得到的小颗粒,通过冷等静压将其制成坯体。在烧结形成莫来石的过程中加入SiC。SiC颗粒主要存在于莫来石内部和氧化铝基质的颗粒中。     

碳化硅纳米粒子改性环氧树脂影响因素的研究

通过先强力磁力搅拌再超声波分散的方式制备了均匀分散的碳化硅纳米粒子改性环氧树脂复合材料。采用X射线衍射仪、扫描电镜和透射电镜以及力学性能测试研究了强力磁力搅拌时间、超声波振荡时间和碳化硅纳米粒子添加量对复合材料性能的影响。结果表明:当强力磁力搅拌、超声波分散时间分别为2 h时,碳化硅纳米粒子的分散效果最佳,复合材料的拉伸强度和弯曲强度均为最大值。随着碳化硅纳米颗粒用量增加,复合材料的拉伸性能和弯曲性能都出现了先增加后减小的趋势。当碳化硅纳米颗粒的质量分数为2%时,材料的拉伸模量、弯曲强度、弯曲模量和弯曲应变达到了最大值1 390.7 MPa,110.53 MPa,3 269.4 MPa和6.62%,较纯环氧树脂分别提高了24.3%,36.8%,28.6%和30.1%。其质量分数为3%时,拉伸强度和断裂伸长率分别达到最大值70.51 MPa和5.09%,比纯环氧树脂提高了49%和20.3%。     

碳化硅纳米晶须的研究进展

本文论述了碳化硅纳米晶须的反应机理和各种制备技术,指出碳化硅纳米晶须主要是通过气固(VS)和气液固(VLS)反应机理生成的,具有纳米尺度的反应原料、催化剂或成核剂是制备碳化硅纳米晶须的关键。     

硅、铝溶胶对碳化硅窑具的结构及性能的影响

以SiC颗粒为骨料,硅微粉为基体相,硅、铝凝胶在高温下形成纳米颗粒作为增强相制备了碳化硅窑具,分析了硅、铝溶胶的添加量对碳化硅窑具烧结特性、力学性能、物相组成及显微结构的影响规律.结果表明,硅、铝溶胶的添加可以增强碳化硅窑具的力学性能.当单独添加硅溶胶量为2.0％时,其抗弯强度可达19.67 MPa,当单独添加铝溶胶的量为1.1％时,抗弯强度为19.26 MPa,当同时添加硅、铝溶胶总量为3.06％时,其抗弯强度可达到18.10 MPa,但过多溶胶的引入会导致碳化硅窑具中气孔的增多从而影响碳化硅窑具的致密化.     

反应烧结碳化硼/碳化硅凝胶注模成形工艺的研究

以碳化硼颗粒为增强相,采用凝胶注模成形工艺制备反应烧结B_4C/SiC复合材料。通过对低粘度、高固相含量碳化硼、炭黑和碳化硅浆料的制备技术以及凝胶注模成形工艺参数的研究,制备出了结构均匀、致密度高的反应烧结碳化硼/碳化硅复合陶瓷。并分析了碳化硼、炭黑和碳化硅料浆制备过程中不同碳化硅颗粒级配、碳化硼含量和碳化硼颗粒大小、球磨时间、料浆pH值、固相含量对料浆粘度的影响。     

太西煤及其煤基活性炭制备纳米碳化硅的比较

以太西煤及其煤基活性炭为碳源,硅酸钠为硅源,Fe(NO_3)_3·9H_2O为催化剂,利用溶胶-凝胶法经碳热还原制备碳化硅粉体,探究不同n(Fe)∶n(Si)对制备的碳化硅的结构和形貌的影响.分别采用XRD,SEM和BET等分析技术对所制备的样品进行表征.结果表明,以太西煤为碳源,制得的碳化硅存在不同程度的堆积缺陷,且随着n(Fe)∶n(Si)的提高,堆积缺陷逐渐减弱,碳化硅的形貌由部分晶须逐渐变为尺寸均匀的纳米颗粒.以煤基活性炭为碳源制备的碳化硅堆积缺陷较弱,碳化硅的结晶度高,而且随着n(Fe)∶n(Si)的提高,碳化硅粒径逐渐增大,但基本保持在50nm~100nm范围.     

硅气氛中PAN碳纤维原位生长碳化硅纳米纤维

1500℃下,采用热蒸发硅碎片的方法,在PAN碳纤维上原位生长碳化硅纳米纤维。讨论了碳化硅纳米纤维的气-固生长机理。X射线衍射图谱表明产物中同时存在碳纤维及βSiC相,通过场发射扫描电镜观察产物,发现碳纤维保持原貌,碳化硅纳米纤维为直线状且表面光滑,直径约为100nm,长度约为50μm。利用透射电镜研究了其形貌和微结构,选区电子衍射图表明该碳化硅纳米纤维为单晶。热蒸发法制备碳化硅纳米纤维有望在碳化硅/碳复合材料等领域得到应用。     

Effect of SiC nanoparticle content and milling time on the microstructural characteristics and properties of Mg-SiC nanocomposites synthesized with powder metallurgy incorporating high-energy ball milling

The fabrication of magnesium nanocomposites with a homogeneous dispersion of nanoparticles has recently become an important issue. In the current study, micro-sized magnesium powders reinforced with 10, 20, and 30 wt% SiC nanoparticles were synthesized through high-energy ball milling using milling times ranging from 1 to 20 h to overcome the segregation and agglomeration of nanoparticles within the magnesium matrix. The milled nanocomposite powders were then consolidated using uniaxial cold pressing and sintering processes. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction were employed to investigate the effects of different milling times and contents of SiC nanoparticles on the evolution of the morphology of Mg–SiC milled powders and the microstructural characteristics of Mg–SiC sintered samples. In addition, once the consolidation process was complete, the relative densities and hardness values of the Mg–SiC nanocomposites were examined. The results indicated that as the content of SiC nanoparticles and the milling time increased, finer and equiaxed nanocomposite powders were obtained, and the average crystallite size of the milled magnesium powder significantly decreased. A homogeneous distribution of the SiC nanoparticles, including up to 30% of weight fraction, in the magnesium matrix was confirmed after 20 h of milling by elemental mapping generated by EDS. Additionally, the XRD analysis revealed that the diffraction peaks of the magnesium broadened while their maximum intensities decreased with increasing the milling time and SiC content. No undesirable phases were formed by interfacial reactions between magnesium and SiC nanoparticles in the milled nanocomposite powder during mechanical alloying. Furthermore, the results showed that both the relative density and hardness value of the Mg–SiC sintered sample improved as the milling time increased. However, the relative density of the Mg–SiC nanocomposite drastically decreased while the hardness significantly improved, as a result of increasing the content of SiC nanoparticles.     

Effect of SiC nanoparticles on in-situ synthesis of SiC whiskers in corundum–mullite–SiC composites obtained by carbothermal reduction

Corundum–mullite–SiC composites were synthesised using a carbothermal reduction method. The effects of SiC nanoparticles and sintering temperatures on the phase transformation of the composites and the synthesis of SiC whiskers were studied by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Results indicated that corundum, mullite, and SiC whiskers were produced as final products at 1600–1650 °C. SiC whiskers were formed through the vapor–solid mechanism. The added SiC nanoparticles worked as nucleating agents to facilitate the carbothermal reduction of aluminosilicates and formation of SiC whiskers. The sample with the added SiC nanoparticles exhibited a high yield of β-SiC of 17.1%. Furthermore, the SiC nanoparticles decreased the formation temperature of SiC whiskers from the original 1600 °C to 1500 °C, and the porosity of the composites was increased from 56.7% to 64.7% by increasing the partial pressure of SiO gas. This study provides an insight into the more efficient synthesis of composites with SiC whiskers through the carbothermal reduction of aluminosilicates.     

Synthesis,properties, and multifarious applications of SiC nanoparticles: A review

The development of particulate materials is accelerating at a tremendous speed and nanoparticles have gradually gained worldwide attention. Among them, silicon carbide (SiC) nanoparticles have attracted much attention due to their excellent performance and great application potential. This article mainly presents a comprehensive overview on the synthesis, properties and potential applications of SiC nanoparticles. Firstly, various synthesis techniques for SiC nanoparticles were discussed, with the classification of solid phase, liquid phase and vapor phase processes. Subsequently, the unique properties of SiC nanoparticles such as surface properties, thermal properties, electrical properties and biocompatibility properties were highlighted. Thereafter, diversified applications of SiC nanoparticles including composites, catalysts, fluorescent biological labels, bioadhesives and flexible field emitters have been discussed. Finally, contents of the article were summarized and outlooks of future research were stated.     

纳米碳化硅的表面改性和分散性研究

采用氢氟酸对原始纳米SiC颗粒进行表面改性,以制备稳定分散的纳米SiC浆料。借助XRD、比表面仪、FT-IR和扫描电子显微镜等对改性前后纳米SiC颗粒进行了表征,发现SiC颗粒表面的Si—O键消失,表明表面的SiO2薄层被去除了,颗粒之间无明显团聚现象。根据比表面积结果,确定改性时间为15 min最好。借助分光光度法,对不同分散剂和超声时间进行研究,确定乙醇为分散剂,超声时间为5 min时,纳米SiC浆料具有较强的分散稳定性。     

Facile synthesis,characterization and antibacterial activity of nanostructured palladium loaded silicon carbide

In this work, noble metal (Palladium) loaded silicon carbide (SiC) nanoparticles have been successfully synthesized using a single step synthetic route and its antibacterial action against gram-negative (E. coli) and gram-positive (S. aureus) bacteria have been investigated. The structural and morphological characterizations of pure SiC and Palladium (Pd) loaded SiC nanoparticles were carried out by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Energy dispersive x-ray spectroscopy (EDX), Elemental mapping and Transmission electron microscopy (TEM). The characterizations results offer substantial proof that the SiC surface was successfully decorated by Pd. Furthermore the EDS analysis reveals that the product contained Pd as well as W and O, thus reaffirming the production of Pd loaded SiC nanoparticles. The MICs and MBCs values examined by standard agar dilution methods show that MICs and MBCs values of pure SiC were >?16 and >?32?mg/ml, respectively against E. coli and S. aureus, whereas Pd loaded SiC nanoparticles exhibited MIC and MBC value of 4?mg/ml and 8?mg/ml, respectively. The morphological and structural alterations caused by SiC and Pd loaded SiC nanoparticles on E. coli and S. aureus cells were further investigated by SEM analysis. A noteworthy improvement in antibacterial performance was observed, when E. coli and S. aureus cells were exposed to Palladium (Pd) nanoparticles (NPs) loaded silicon carbide (SiC). The results obtained show a significant impact by loading Pd on SiC in the deactivation of microorganisms in vitro.     

Fabrication of ultra-small SiC nanoparticles with adjustable size,stoichiometry and photoluminescence by AC multi-arc plasmas

Ultra-small SiC nanoparticles with sizes smaller than 10 nm have wide prospects in optoelectronics and biomedical engineering, but challenges in their synthetic methods still limit their practical applications. In this paper, an AC multi-arc plasma device was designed for the continuous gas-phase synthesis of ultra-small SiC nanoparticles. SiC nanoparticles with an average size range of 7–10 nm, abundant surface functional groups, and obvious photoluminescence emission were fabricated by the decomposition of triethylsilane in AC multi-arc plasmas. The synthesized SiC nanoparticles had a typical core-shell structure, whose core was mainly β-SiC and whose shell was covered by a few carbon layers. It was also found that the buffer gas effectively adjusted the particle size, crystal texture, stoichiometric ratio of each element, functional group composition, and photoluminescence. These adjustments were meaningful for the controllable preparation and practical utilization of ultra-small SiC nanoparticles. According to the product characteristics, the formation path of SiC nanoparticles and the influence of buffer gases were proposed.     

Effects of SiC nanoparticles on synthesis and antimicrobial activity of TiCu nanocrystalline powder

Effects of SiC nanoparticles addition on synthesis and antibacterial properties of TiCu nanocrystalline powder prepared through high energy mechanical milling were studied. The results showed that the synthesis of TiCu powder in the presence of the nanoparticles was accelerated and after mechanical alloying for 20 h, a TiCu/SiC nanocrystalline powder with the crystallite size <5 nm, and 3.3% lattice micro-strain obtained. Further milling resulted in fully amorphous TiCu intermetallic alloy with more uniform distribution of SiC nanoparticles. The antibacterial activity of the synthesized powders was investigated by disk diffusion test. The TiCu/SiC nanocomposites showed enhanced antibacterial effect against S. aureus and E. coli, and with increasing SiC content, the antibacterial behaviour was improved. This behaviour is attributed to high Cu²⁺ ion release as a result of particle size refinement with increasing SiC nanoparticles.     

Thermal plasma synthesis of Si/SiC nanoparticles from silicon and activated carbon powders

In this study, Si/SiC nanocomposites were synthesized by non-transferred arc thermal plasma processing of micron-sized SiC powder. First, micron-sized SiC was synthesized by solid-state method where waste silicon (Si) and activated carbon (C) powder were used as precursor materials. The effect of Si/C mole ratio and solid-state synthesis temperature on structural and phase formation of SiC was investigated. Diffraction pattern confirmed the formation of SiC at 1300 °C. High C content was required for the synthesis of pure SiC as Si remained unreacted when Si/C mole ratio was below 1/1.5. Highly agglomerated micron-size (0.6–10 µm) SiC particles were formed after solid-state synthesis. Thermal plasma processing of solid-state synthesized micron-sized SiC resulted into the formation of uniformly dispersed (20–60 nm) Si/SiC nanoparticles. It was proposed that Si/SiC nanocomposites were formed due to partial decomposition of SiC during high temperature plasma processing. The formation of Si/SiC nanoparticles from micron-sized SiC was resulted from dissociation of grains from their grain boundary during plasma processing.