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您的检索式：作者名="Kangwei MAO"
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| 1 | Role of in-situ formed free carbon on electromagnetic absorption properties of polymer-derived SiC ceramics显示文摘In order to enhance dielectric properties of polymer-derived SiC ceramics,a novel single-source-precursor was synthesized by the reaction of an allylhydrido polycarbosilane(AHPCS)and divinyl benzene(DVB)to form carbon-rich SiC.As expected,the free carbon contents of resultant SiC ceramics annealed at 1600℃are significantly enhanced from 6.62 wt%to 44.67 wt%.After annealing at 900-1600℃,the obtained carbon-rich SiC ceramics undergo phase separation from amorphous to crystalline feature where superfine SiC nanocrystals and turbostratic carbon networks are dispersed in an amorphous SiC(O)matrix.The dielectric properties and electromagnetic(EM)absorption performance of as-synthesized carbon-rich SiC ceramics are significantly improved by increasing the structural order and content of free carbon.For the 1600℃ ceramics mixed with paraffin wax,the minimum reflection coefficient(RCmin)reaches-56.8 dB at 15.2 GHz with the thickness of 1.51 mm and a relatively broad effective bandwidth(the bandwidth of RC values lower than-10 dB)of 4.43 GHz,indicating the excellent EM absorption performance.The carbon-rich SiC ceramics have to be considered as harsh environmental EM absorbers with excellent chemical stability,high temperature,and oxidation and corrosion resistance. | Zhaoju YU Xuan LV Kangwei MAO Yujing YANG Anhua LIU | 2020 | Journal of Advanced Ceramics2020，9，5： | 5 |
| 2 | Single-source-precursor synthesis and phase evolution of SiC-TaC-C ceramic nanocomposites containing core-shell structured TaC@C nanoparticles显示文摘A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane(allylhydridopolycarbosilane,AHPCS)and tantalum(V)chloride(TaCls),which was confirmed by Fourier transform infrared spectra(FTIR)measurement.After pyrolysis of the resultant single-source-precursors at 900'C,amorphous ceramic powders were obtained.The 900 C ceramics were anncaled at different temperatures in the range of 1200-1600℃ to gain SiC-TaC-C nanocomposites.The phase evolution of ceramic nanocomposites was investigated by X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results indicate that the TaC starts to crystallize at lower temperature than theβ-SiC.It is particularly worth pointing out that the unique core-shell structured TaC-C nanoparticles were in-situ formed and homogeneously distributed in the ceramic matrix after annealing at 1400 C.Even at a high temperature of 1600 C,the grain sizes ofβ-SiC and TaC are smaller than 30 nm,flilling the definition of nanocomposites.The present study related to SiC-TaC C nanocomposites paves a new road for enriching ultra-high temperature ceramic family suitable for structural/functional applications in harsh environment. | Zhaoju YU Yujing YANG Kangwei MAO Yao FENG Qingbo WEN Ralf RIEDEL | 2020 | Journal of Advanced Ceramics2020，9，3： | 5 |
| 3 | Single-source-precursor synthesis of porous W-containing SiC-based nanocomposites as hydrogen evolution reaction electrocatalysts显示文摘In this paper,W-containing SiC-based ceramic nanocomposites were successfully prepared by a polymer-derived ceramic approach using allylhydridopolycarbosilane(AHPCS)as a SiC source,WC16 as a tungsten source,polystyrene(PS)as a pore forming agent as well as divinyl benzene(DVB)as a carbon rich source.High-temperature phase behavior of the W-containing SiC-based ceramics after heat treatment was studied,showing that excessive DVB content in the feed will inhibit the crystallinity of W-containing nanoparticles in the final ceramic nanocomposites.The high specific surface area(SSA)of 169.4-276.9 m^(2)/g can be maintained even at high temperature in the range of 1400-1500℃,due to the carbothermal reaction which usually occurs between 1300 and 1400℃.All prepared W-containing SiC-based nanocomposites reveal electrocatalytic activity for the hydrogen evolution reaction(HER).In detail,compared with reversible hydrogen electrode(RHE),the ceramic sample PWA-2-1300 after heat treatment at 1300℃ has the smallest overpotential of 286 mV when the current density is 10 mA·cm^(-2) in acid medium,indicating the promising perspective in the water splitting field. | Zhaoju YU Kangwei MAO Yao FENG | 2021 | Journal of Advanced Ceramics2021，10，6： | 1 |
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