Abstract

Nonoxide ceramics microspheres with multiple compositions are attractive for wide applications especially in thermal insulation science. The flower-like Fe-doped Si–C–N ceramic microspheres with the average size of about 1 μm were fabricated from polyvinylsilazane and ferrocene precursor through polymer-derived ceramics technology combined with emulsion polymerization method. The properties of the resultant microspheres were characterized by FTIR, SEM-EDX, VSM, TGA, and XRD. The morphology and size of the microspheres could be tuned by changing of ferrocene content, cross-linking time, and pyrolysis temperature. The ceramic microspheres were estimated to be composed of SiC/Si₃N₄ and α-Fe/Fe₂O₃ crystal phase, and the folding sheets on the surface induced the flower-like morphology due to phase separation and crystal rearrangement. The effective extinction coefficient of silica aerogels opacified with 10 wt% of Fe-doped Si–C–N microspheres increased with rising pyrolysis temperature, the maximum value of e* reached 27.5 cm²/g at 1300 °C. Moreover, the microspheres showed weak room temperatures ferromagnetism, which was facilitated to alignment in fabrication and recycle, make them an ideal candidate for aerogels in infrared shielding application.

Flower-like Fe-doped Si–C–N ceramic particles were prepared through a controllable emulsion polymerization method with PVSZ and ferrocene precursor. With emulsion droplet as soft templates, flower-like Fe-doped Si–C–N ceramic particles self-assembled with two-dimensional nanosheets via PDC method possessed a higher specific surface area. The resulting Fe-doped Si–C–N ceramics particles will allow for a wide scope of potential application in many fields, such as infrared opacifiers, reinforcing phases, and gas sensor.

中文翻译：

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具有花状形态和红外消光特性的Fe掺杂Si–C–N陶瓷微球的制备

摘要

具有多种成分的非氧化物陶瓷微球对于广泛的应用具有吸引力，特别是在隔热科学中。通过聚合物衍生的陶瓷技术与乳液聚合法相结合，由聚乙烯基硅氮烷和二茂铁前驱体制备了平均大小约为1μm的花状掺Fe的Si–C–N陶瓷微球。通过FTIR，SEM-EDX，VSM，TGA和XRD表征了所得微球的性质。微球的形态和尺寸可以通过改变二茂铁含量，交联时间和热解温度来调节。估计陶瓷微球由SiC / Si ₃ N ₄和α-Fe/ Fe ₂ O _3组成晶体相，并且由于相分离和晶体重排，表面上的折叠片诱导出花状形态。随着热解温度的升高，掺有10 wt％的Fe掺杂的Si–C–N微球不透明的二氧化硅气凝胶的有效消光系数增加，在1300°C时e *的最大值达到27.5 cm ² / g。而且，微球显示出弱的室温铁磁性，这有助于在制造和回收中进行对准，使其成为红外屏蔽应用中气凝胶的理想候选者。

通过PVSZ和二茂铁前体的可控乳液聚合法制备了花状掺铁的Si–C–N陶瓷颗粒。用乳液滴作为软模板，通过PDC方法与二维纳米片自组装的花状掺Fe的Si–C–N陶瓷颗粒具有较高的比表面积。所得的Fe掺杂的Si–C–N陶瓷颗粒将在许多领域（例如红外遮光剂，增强相和气体传感器）中具有广泛的潜在应用范围。