纳米SiC颗粒增强反应烧结碳化硼复合材料的研究

Studies on the Silicon Carbide Nano-Particulates reinforced Reaction Bonded Boron Carbide Composites

摘要:

采用真空熔渗法，通过对B4C-C素坯于1550 ℃渗Si，得到了较致密的反应结合碳化硼陶瓷复合材料。通过生成SiC纳米颗粒对材料进行强化，并探讨了纳米SiC颗粒对材料组织与性能的影响及其强韧化机理。实验表明，材料包括B4C、Si、SiC和B12(C,Si,B)3四相。结果表明，选取酚醛树脂作为外加碳源，可在材料中成功引入细小的SiC纳米颗粒，使复合材料的抗折强度、断裂韧性和维氏硬度较以炭黑为外加碳源的材料，分别增加了35 %、36 %和15 %，分别高达442 MPa、4.9 MPa?m1/2和23 GPa。

Abstract:

Reaction bonded boron carbide (RBBC) composites were fabricated based on molten Si infiltration method. The mechanical properties of the composites were improved by the reaction formed silicon carbide (SiC) nano-particulates. The role of SiC nano-particulates in the microstructure, density and mechanical properties of RBBC composites, and the strengthening mechanism were researched. The XRD results showed that the composites consist of four phases, namely, B4C, Si, reaction formed SiC and ternary phase B12(C,Si,B)3. The SiC nano-particulates were introduced in the RBBC composites by using phenolic resin as carbon sources. The bending strength, fracture toughness and Vickers-hardness of the RBBC composites fabricated with phenolic resin as carbon sources were 442 MPa, 4.9 MPa?m1/2 and 23 GPa, which increased of 35 %, 36 % and 15 % respectively, compared with those of RBBC composites fabricated with black carbon as carbon sources. Clearly, an introduction of the nano-sized SiC particles to RBBC composites is responsible for the increase in the mechanical properties of the composites.