A kind of silicon carbide ceramic matrix composite material with layered distribution of rare earth silicate and preparation method thereof
A silicon carbide ceramic base and rare earth silicate technology, which is applied in the field of silicon carbide ceramic base composite material with rare earth silicate layered distribution and its preparation, can solve problems such as poor water and oxygen resistance, and achieve excellent mechanical properties, The effect of improving the intrinsic resistance to water and oxygen
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Embodiment 1
[0058](1) Pretreatment of fiber preform: perform chemical vapor infiltration on the three-dimensional needle-punched carbon fiber preform to prepare a pyrolytic carbon interface layer with a thickness of about 200 nm and a pre-deposited SiC layer with a thickness of 1 μm;
[0059] (2) Preparation of rare earth salt solution: Yttrium nitrate hexahydrate (Y(NO 3 ) 3 ·6H 2 0) powder is dissolved in ethanol, and magnetic stirring obtains the yttrium nitrate / ethanol solution of 1.5mol / L in 24 hours;
[0060] (3) Surface coating and impregnation: soak the preform with the yttrium nitrate / ethanol solution in (2) by surface coating method, and then evaporate to dryness at 90°C for 1 hour to obtain C f / SiC-Y(NO 3 ) 3 ;
[0061] (4) pyrolysis: the C in (3) f / SiC-Y(NO 3 ) 3 Put it into a carbon tube furnace and pyrolyze it in an argon atmosphere, the pyrolysis temperature is 700°C, and keep it warm for 30 minutes to get C f / SiC-Y 2 o 3 ;
[0062] (5) Repeat (3) (4) steps t...
Embodiment 2
[0068] The preparation steps are similar to those in Example 1, except that in step (1), a two-dimensionally stitched silicon carbide fiber preform is used, and a boron nitride interface phase with a thickness of about 200 nm and a preform of 3 μm are prepared on the fiber. A SiC layer is deposited.
[0069] SiC prepared in this embodiment 2 f / SiC-(Y 2 Si 2 o 7 ) 3 The cross-sectional SEM photograph of the composite material is as Figure 4 shown, from Figure 4 As can be seen in the white Y 2 Si 2 o 7 The enrichment area is distributed in multiple layers around the fiber bundle, where Y 2 Si 2 o 7 The thickness of the layer is generally distributed between 200-2000 nm, and the thickness of the SiC layer is 3-5 μm. The composite material prepared in the present embodiment 2 is subjected to a water-oxygen corrosion test, the corrosion temperature is 1400°C, and the atmosphere is 500ml / min (200ml O 2 +300ml H 2 O). After 70 hours of corrosion, the mass loss was -...
Embodiment 3
[0071] The preparation steps are similar to those in Example 1, except that in step (8), steps (3) to (7) are repeated once to fill the SiC matrix. The C prepared in this embodiment 3 f / SiC-(Y 2 Si 2 o 7 ) 2 The composite material was subjected to the water-oxygen corrosion test, the corrosion temperature was 1400°C, the atmosphere was 500ml / min (200ml O 2 +300ml H 2 O). After 70 hours of corrosion, the mass loss was 10.40%. C prepared in this example f / SiC-(Y 2 Si 2 o 7 ) 3 The flexural strength of the composite material is 422±21MPa.
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Abstract
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