BNNTs/B_4C层状复合材料的制备与性能研究

Preparation and Properties of BNNTS/B_4C Laminates

以碳化硼(B4C)粉为主要原料,硼(B)粉为烧结助剂,氮化硼纳米管(BNNTs)为补强增韧剂,聚乙烯亚胺(PEI)为分散剂,羟丙基甲基纤维素(HPMC)为粘结剂,聚乙二醇(PEG)为增塑剂,采用水基流延成型工艺和热压烧结法制备出BNNTs/B4C层状复合材料。研究了固含量、分散剂含量、增塑剂与粘结剂质量比值(R值)对流延浆料粘度的影响。采用硬度计、万能试验机、X射线衍射仪(XRD)、扫描电镜(SEM)等手段对样品进行了表征。实验结果表明:当PEI、HPMC、PEG的加入量分别为1.5%、5%和5%(质量分数,下同)时可获得固含量为45%的B4C水基流延浆料。样品于2050℃、30 MPa下热压30 min可获得致密度高达97.5%的BNNTs/B4C层状复合材料,其维氏硬度、抗弯强度、断裂韧性分别达38.2 GPa、516.34 MPa和6.97 MPa·m1/2。

BNNTs/B_4C laminates were prepared by aqueous tape casting and hot-pressing process using B_4C as the main raw material, B powder as sintering aids, BNNTs as toughening phase, PEI as dispersant, HPMC as binder and PEG as plasticizer. The influences of solid content, dispersant content and the ratio(R value) of plasticizer to binder on the viscosity of slurries were studied. The samples were characterized by means of hardness tester, universal testing machine, X-ray diffraction(XRD) and scanning electron microscopy(SEM). The results indicate that the solid content of B_4C slurry reaches 45% when the content of PEI, HPMC and PEG is 1.5%, 5%, and 5%, respectively. The relative density of BNNTs/B_4C laminates hot-pressed at 2050 oC and 30 MPa for 30 min is up to 97.5%. The vickers hardness, flexural strength and fracture toughness of BNNTs/B_4C laminates is 38.2 GPa, 516.34 MPa and 6.97 MPa·m1/2, respectively.