纳米ZrB2粉体放电等离子烧结制备ZrB2基超高温陶瓷的系统研究

A systematical investigation on the ZrB2-based ultra-high temperature ceramics fabricated by SPS using nanosized ZrB2 powders

摘要:

本文采用纳米ZrB2粉体系统研究了ZrB2基超高温陶瓷的放电等离子烧结行为。由于采用纳米粉体，单相ZrB2在1550℃的低温下即发生快速的致密化烧结。ZrB2-SiC陶瓷经1800℃放电等离子烧结后可实现完全致密化，并且材料的弯曲强度高达1078±162 MPa。在1700℃采用放电等离子烧结成功制备了ZrB2-SiC-Cf复合材料，材料断口表现出明显的纤维拔出现象，导致其具有高的断裂韧性值(6.04 MPa·m1/2)和非脆性断裂的模式。同时，ZrB2-SiC-Cf复合材料具有很高的临界热冲击温差（627℃），表明该材料具有优异的抗热冲击性能。

Abstract:

The spark plasma sintering behaviors of ZrB2-based ultra-high temperature ceramics were systematically investigated using nanosized ZrB2 powders. Rapid densification occurred at low temperature (1550 oC) for monolithic ZrB2 due to the nanosized powders. ZrB2-SiC ceramic achieved full densification at 1800 oC by SPS resulting in a high flexural strength of 1078±162 MPa. ZrB2-SiC-Cf composite was successfully prepared by SPS at 1700 oC. The composite showed obvious fiber pull-out on the fracture surface, leading to a high fracture toughness (6.04 MPa·m1/2) and a non-brittle fracture mode. Meanwhile, a high critical thermal shock temperature difference of 627 oC was obtained for ZrB2-SiC-Cf implying an excellent thermal shock resistance of such material.