▎ 摘　　要

NOVELTY - Preparing multi-layer wave-absorbing ceramic matrix composite material comprises e.g. (i) selecting a two-dimensional fabric woven with continuous fibers and drying it in a vacuum oven for 2-5 hours, taking it out, placing it in a high-temperature vacuum or inert atmosphere to remove sizing agent on surface of fiber fabric, (ii) preparing a boron nitride interface layer on the surface of the fiber fabric treated in resultant step by controlling the deposition time, (iii) taking the ceramic precursor, stirring and mixing, (iv) immersing fiber fabric with boron nitride interface layer in mixed ceramic precursors with different electromagnetic properties to obtain fiber fabrics with different electromagnetic properties, (v) laminating the fiber fabrics with different electromagnetic properties in multiple layers, placing it in the mold and curing, (vi) immersing composite material in a ceramic precursor, (viii) using ceramic precursor to impregnating and performing densification. USE - The method is useful for preparing multi-layer wave-absorbing ceramic matrix composite material c. ADVANTAGE - The method: is simple and suitable for forming the large-size complex component; realizes the control of different electromagnetic properties of multi-layer fiber fabric by changing the type and content of the electromagnetic nano-particles; adjusting the wave-absorbing performance of ceramic-based composite material; satisfies the use requirement of different uses. DETAILED DESCRIPTION - Preparing multi-layer wave-absorbing ceramic matrix composite material comprises e.g. (i) selecting a two-dimensional fabric woven with continuous fibers and drying it in a vacuum oven for 2-5 hours, taking it out, placing it in a high-temperature vacuum or inert atmosphere at 800-100 degrees C for 0.5-1 hour to remove the sizing agent on the surface of the fiber fabric, (ii) preparing a boron nitride interface layer on the surface of the fiber fabric treated in resultant step by controlling the deposition time, (iii) taking the ceramic precursor with a viscosity of 20-200cP, stirring and mixing carried out by ball milling and dispersing the electromagnetic nanoparticles in the precursor, changing the type and content of electromagnetic nanoparticles, preparing hybrid precursors with different electromagnetic properties to realize the control of the different electromagnetic properties of the hybrid precursors, (iv) immersing the fiber fabric with the boron nitride interface layer prepared in step (ii) in the mixed ceramic precursors with different electromagnetic properties prepared in resultant step for 6-10 hours to obtain fiber fabrics with different electromagnetic properties, (v) according to the structure design of the multi-layer absorbing composite material, laminating the fiber fabrics with different electromagnetic properties obtained in resultant step in multiple layers, then placing it in the mold, heating and pressing to complete the curing, (vi) immersing the resultant composite material in a ceramic precursor under high temperature vacuum or inert atmosphere to complete the cracking, (viii) using ceramic precursor with a viscosity of 20-200cP to impregnating the composite material with a cyclic operation of cracking and performing densification.