C_f/SiC-ZrC Ultrahigh Temperature Composite And Its ZrB₂-SiC Anti-oxidation Ceramic Coating

C_f/SiC-ZrC composite material ratio,high specific modulus,high hardness,wear resistance,erosion resistance and the characteristics of low density,is represented by the special craft ultra-high speed space future development direction of strategic weapons.However,C_f/SiC-ZrC composites have the problem of high temperature oxidation,and oxygen corrodes the fiber at high temperature,leading to decreased material performance.Ultra high temperature ceramic has good high temperature oxidation resistance and thermal shock resistance,with oxidation ceramic coating preparation method?hot pressing method?combine the advantages of both,can improve the C_f/SiC-ZrC composite antioxidant properties.In this paper,C_f/SiC composites were prepared by chemical vapor phase permeation process?CVI?and modified by precursor impregnation cracking process?PIP?to prepare C_f/SiC-ZrC composites.Respectively from different powder content in the mixed slurry,using ZrC is added in the organic precursor solution and SiC ceramic powder preparation of C_f/SiC-ZrC composite material,its internal structure is compact,to improve the C_f/SiC-ZrC composite material density,the purpose of shortening the period of preparation.The density of C_f/SiC-ZrC composite increased the fastest when the mass fraction of inert powder was added at 15%and soaked for 8 cycles,and the internal density was the highest.Pressure impregnation can effectively shorten the impregnation period and increase the density of C_f/SiC-ZrC composite.When the vacuum impregnation time is 1.5 hours and the impregnation pressure reaches 6 MPa,after 5 cycles of impregnation,C_f/SiC-ZrC composite material has the best density,the highest impregnation efficiency and the best impregnation effect.In this paper,ZrB₂-SiC antioxidant ceramic coatings were prepared by hot pressing with C_f/SiC-ZrC composite as matrix.The thermal and mechanical properties of C_f/SiC-ZrC composites and ZrB₂-SiC anti-oxidation ceramic coatings were determined,providing theoretical basis for the preparation of ZrB₂-SiC anti-oxidation ceramic coatings.Design control experiment to investigate factors for ZrB₂-SiC oxidation ceramic coating composition ratio?ZrB₂ and SiC volume ratio of 3:1,4:1 and 5:1?,sintering temperature?1650 ^?,1750 ^?,1850 ^??and pressure?15 MPa,20 MPa?.Through the spraying method in preparation of sample surface ZrB₂-SiC oxidation ceramic coatings,analyzing and comparing different ZrB₂and SiC volume than the preparation of coating microstructure,determine the ZrB₂ and SiC volume ratio 4:1 for optimal matching.Via hot pressing method in the surface of the sample preparation of ZrB₂-SiC oxidation ceramic coatings,analysis and comparison of different sintering temperature,pressure,the preparation of coating microstructure,under 1750 ^?,15MPa coating preparation by high density,and C_f/SiC-ZrC composite material combined with the best.In this paper,the TG-DTA analysis of ZrB₂-SiC ceramics is carried out,and the oxidation mechanism of ZrB₂-SiC ceramics is discussed,which provides theoretical basis for the study of improving its antioxidant performance.ZrB₂-SiC oxidation ceramic coatings for the oxidation of weightlessness analysis,studied the composition ratio,sintering temperature and pressure on the oxidation resistance coating,the influence of the research results show that the sample ZS-11?sintering temperature:1750 ^?;Pressure:20 MPa?has the lowest rate of oxidative weight loss.ZrB₂-SiC ceramic oxide coating on the microstructure and phase composition analysis,ZrB₂-SiC oxidation ceramic coating surface oxidation reaction after the ZrSiO₄ facies,SiO₂ and ZrO₂ phase formation,and there are a few small holes can't heal.