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以二硼化锆(ZrB_2)为硬夹层,氮化硼纳米管(BNNTs)为基体B_4C层补强增韧剂,聚乙烯醇缩丁醛(PVB)为粘结剂,邻苯二甲酸二辛酯(DOP)为增塑剂,采用非水基流延成型工艺制备ZrB_2流延膜。研究了PVB含量、DOP含量以及固相含量对ZrB_2流延浆料流变性能的影响。实验结果表明:当PVB和DOP的加入量分别为5 wt%和6 wt%时可获得固含量为50 wt%的均匀稳定ZrB_2流延浆料,采用流延成型制备出不同厚度的ZrB_2流延膜。与本实验室已制备的B4C-BNNTS流延膜进行叠层、热压烧结制备出ZrB_2/B_4C-BNNTs层状复合材料。实验结果表明,当基体层与硬夹层的层厚比为2∶1时,在2000℃、压力30 MPa下热压烧结得到的ZrB_2/B_4C-BNNTs层状复合材料的力学性能最佳,其维氏硬度和断裂韧性分别为39.6 GPa、7.69 MPa·m~(1/2)。
In this paper, zirconium diboride (ZrB_2) as hard interlayer, boron nitride nanotubes (BNNTs) as matrix B_4C reinforcing toughening agent, polyvinyl butyral (PVB) as binder, Ester (DOP) as plasticizer, ZrB 2 cast film was prepared by non-aqueous casting process. The effects of PVB content, DOP content and solid content on the rheological properties of ZrB_2 slurry were investigated. The experimental results show that when the amount of PVB and DOP added is 5 wt% and 6 wt%, respectively, a uniform and stable ZrB2 cast slurry with a solid content of 50 wt% can be obtained, and cast films of different thicknesses are prepared by casting membrane. The B4C-BNNTS cast films prepared in our laboratory were laminated and hot-pressed to prepare ZrB_2 / B_4C-BNNTs layered composites. The experimental results show that the mechanical properties of ZrB_2 / B_4C-BNNTs composites prepared by hot pressing at 2000 ℃ and pressure of 30 MPa are the best when the thickness ratio of substrate to hard interlayer is 2:1. Hardness and fracture toughness were 39.6 GPa and 7.69 MPa · m ~ (1/2), respectively.