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以纤维素和凹凸棒石(PG)为原料,在220℃下水热24h制备凹凸棒石/炭(PG/C)复合材料。采用浸渍-炭化工艺在炭/炭(C/C)复合材料中引入PG/C作为添加剂,一步热压对材料最终成型,原位获得C/C-陶瓷/C复合材料。研究了添加PG/C对C/C力学性能和抗氧化性能的影响。结果表明:PG/C在热压过程中转变为顽辉石/C,顽辉石/C通过“填充”和“桥联”起增强作用,顽辉石陶瓷表面负载纳米炭层有效避免了陶瓷相与基体炭间弱结合的产生。随着PG/C中表面负载纳米炭含量的减少,C/C的强度逐渐增加。当炭含量为13%的PG/C作为添加剂时,C/C的抗弯强度为263MPa,弹性模量为47GPa,相对于没有添加剂的C/C抗弯强度提高了45%,弹性模量提高了42%;相对于以PG作为添加剂的C/C抗弯强度提高了16%,弹性模量提高了27%。添加PG/C使C/C抗氧化性得到了提高;1 000℃下C/C的质量损失降低了12%~18%。
The attapulgite / charcoal (PG / C) composites were prepared by hydrothermal treatment at 220 ℃ for 24 h with cellulose and attapulgite (PG) as raw materials. The impregnation-carbonization process was used to introduce PG / C into the carbon / carbon composite (C / C) composites. The final molding of the composites was carried out by one-step hot pressing, and the C / C ceramics / C composites were obtained in situ. The effects of PG / C addition on the mechanical properties and oxidation resistance of C / C were studied. The results show that PG / C is transformed into enstatite / C during autoclaving and enstatite / C plays an enhanced role through “filling” and “bridging” Which effectively avoids the weak bond between the ceramic phase and the matrix carbon. With the decrease of surface carbon nanotubes loading in PG / C, the strength of C / C increases gradually. When PG / C with carbon content of 13% was used as additive, the flexural strength of C / C was 263 MPa, the elastic modulus was 47 GPa, the flexural strength of C / C increased 45% and the elastic modulus increased 42%, C / C flexural strength increased by 16% and modulus of elasticity increased by 27% relative to PG as an additive. The addition of PG / C enhanced the C / C oxidation resistance; the mass loss of C / C at 1000 ℃ decreased by 12% ~ 18%.