Please cite this article in press as: W. Duan, et al., Microwave-absorption properties of SiOC ceramics derived from novel hyperbranched ferrocene-containing polysiloxane, J Eur Ceram Soc (2016), http://dx.doi.org/10.1016/j.jeurceramsoc.2016.12.038 ARTICLE IN PRESS G Model JECS-10990; No. of Pages 10 Journal of the European Ceramic Society xxx (2016) xxx–xxx Contents lists available at www.sciencedirect.com Journal of the European Ceramic Society journal homepage: www.elsevier.com/locate/jeurceramsoc Feature article Microwave-absorption properties of SiOC ceramics derived from novel hyperbranched ferrocene-containing polysiloxane Wenyan Duan a , Xiaowei Yin a,∗ , Chunjia Luo b , Jie Kong b , Fang Ye a , Hongxing Pan a a Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, Xi’an 710072, China b MOE Key Laboratory of Space Applied Physics and Chemistry, Shaanxi Key Laboratory of Macromolecular Science and Technology, School of Science, Northwestern Polytechnical University, Xi’an 710072, China a r t i c l e i n f o Article history: Received 15 November 2016 Received in revised form 22 December 2016 Accepted 22 December 2016 Available online xxx Keywords: SiOC ceramic Chemical modification approach Microwave-absorption properties a b s t r a c t In this contribution, we design a novel strategy to synthesize SiOC ceramics by pyrolysis of hyperbranched ferrocene-containing polysiloxane (HBPSO-VF) which are synthesized by the reaction of polysiloxane (PSO) with 1,1 ′ -Bis(dimethylvinylsilyl)ferrocene (VF). This SiOC ceramics show much lower crystalliza- tion temperature because of the capability of HBPSO-VF to incorporate metallic iron into the backbone of PSO. The usage of HBPSO-VF offers enhanced ceramic yield of 83 wt% at 1200 ◦ C due to the deep cross- linking of hydrosilylation. Nano-sized SiC and turbostratic carbons are separated from amorphous SiOC phase when it is annealed at 1100 ◦ C, while crystallization temperature is 1400 ◦ C when PSO is used as polymer precursors. The minimum reflection coefficient (RC min ) of this nanocrystal-containing ceramic reaches −46 dB, exhibiting a promising prospect as a kind of electromagnetic wave (EMW) absorbing materials. This method also can be further extended to develop other functional Si-based polymer derived ceramic (PDC) systems for EMW absorption and shielding applications. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Nowadays, fabrication of electromagnetic wave (EMW) absorp- tion materials used in the fields of defense stealth technology is in great demand and tremendous effort has been devoted to high-performance absorption materials to eliminate adverse EMW irradiations caused by Doppler, weather radar, TV picture trans- mission, and telephone microwave relay and civil and military applications covering the frequency range of 8.2–12.4 GHz (X- band) [1–8]. Recently, graphene, carbon nanotubes, SiC, ZnO, and Mn 2 O 3 nanoparticle composites have attracted great interest as EMW absorption materials due to their special physical and chem- ical properties [5,9–21]. Compared with above ceramics , Si-based polymer derived ceramics (PDCs) offer the possibility of flexible plastic-technical processing, for instance by means of injection molding or extrusion without the employment of additional binder systems [22–26]. PDCs were used as promising candidates for these demanding applications owing to their special microstruc- ture which contains semiconductor (silicon carbide) or electrically conductive phase (carbon) uniformly distributed in the amorphous material [27–33]. ∗ Corresponding author. E-mail address: yinxw@nwpu.edu.cn (X. Yin). Fig. 1 shows the EMW absorbing properties of PDCs annealed at different temperature in X band. As shown in Fig. 1, PDC-SiC, PDC-SiOC, PDC-SiCN, and PDC-SiBCN were derived from poly- carbosilanes (PCS), polysiloxane (PSO), polysilazane (PSN), and polyborosilazane (PBSZ), respectively. Reflection coefficient (RC, when RC is smaller than −10 dB, more than 90% of the EM power is attenuated) and efficient absorption bandwidth (EAB, the corresponding frequency range with which the RC is smaller than −10 dB) are used to evaluate the performance of microwave absorption. The absorption properties of PDCs are related to semi- conducting or conducting nano-phases which can be tailored by changing the chemistry of architecture structure of polymer pre- cursors, and tuning the microstructure of the PDCs [34]. However, PDCs derived from pure precursor polymer at even very high tem- perature usually show poor absorption properties because of their thermal and chemical stability at temperatures up to 1500 ◦ C and even 2000 ◦ C for boron-containing PDCs. Usually, adding fillers into polymer precursors can enhance the absorption properties of PDCs [30,31,35–37]. Although PDCs with fillers could attain a low reflec- tion coefficient (RC min ≤ −20 dB), the heat-treatment temperature were always very high (≥1400 ◦ C). Therefore, it is necessary to select a suitable preparation method and develop a new kind of PDCs with excellent EMW attenuation capability (RC min ≤ −40 dB) and low heat-treatment temperature (≤1200 ◦ C). http://dx.doi.org/10.1016/j.jeurceramsoc.2016.12.038 0955-2219/© 2016 Elsevier Ltd. All rights reserved.