Electromagnetic(EM)wave-absorbing materials with high-temperature-resistance are urgently desirable to eliminate EM interference in extreme conditions.Precursor derived ceramics(PDC)route is being evolved as an effect...Electromagnetic(EM)wave-absorbing materials with high-temperature-resistance are urgently desirable to eliminate EM interference in extreme conditions.Precursor derived ceramics(PDC)route is being evolved as an effective strategy to solve the puzzle.Herein,a single source hyperbranched polyborosi-lazane precursor containing hafnium(hb-PBSZ-Hf)is introduced and the SiBCNHf ceramic is obtained by further pyrolysis.The micro-sized tissues including HfC,SiC,HfB 2 nanocrystals and segregated carbons are in situ generated during annealing which not only increase EM wave absorption ability(minimum re-flection coefficient(RC_(min))is-56.71 dB with a thickness of 2.5 mm,effective absorption bandwidth(EAB)is 3.4 GHz),but also improve antioxidation property(less than 2 wt.%mass fluctuation at 1400℃in air).Theoretical simulation of complex permittivity suggests that SiBCNHf ceramic has an RC_(min)of less than-5 dB for the whole X-band even at 1100℃.Such SiBCNHf ceramic with superior high-temperature-resistance and antioxidation performance derived from single source precursors possesses great potential for EM wave absorbing coatings in high-temperature and harsh environments.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars(No.52025034)National Science and Technology Major Project of China(No.J2019-VI-0017-0132).
文摘Electromagnetic(EM)wave-absorbing materials with high-temperature-resistance are urgently desirable to eliminate EM interference in extreme conditions.Precursor derived ceramics(PDC)route is being evolved as an effective strategy to solve the puzzle.Herein,a single source hyperbranched polyborosi-lazane precursor containing hafnium(hb-PBSZ-Hf)is introduced and the SiBCNHf ceramic is obtained by further pyrolysis.The micro-sized tissues including HfC,SiC,HfB 2 nanocrystals and segregated carbons are in situ generated during annealing which not only increase EM wave absorption ability(minimum re-flection coefficient(RC_(min))is-56.71 dB with a thickness of 2.5 mm,effective absorption bandwidth(EAB)is 3.4 GHz),but also improve antioxidation property(less than 2 wt.%mass fluctuation at 1400℃in air).Theoretical simulation of complex permittivity suggests that SiBCNHf ceramic has an RC_(min)of less than-5 dB for the whole X-band even at 1100℃.Such SiBCNHf ceramic with superior high-temperature-resistance and antioxidation performance derived from single source precursors possesses great potential for EM wave absorbing coatings in high-temperature and harsh environments.
