Ultra-low temperature spark plasma sintering of super wear-resistant hard B4C composites

The feasibility was investigated of fabricating super wear-resistant hard B4C composites by spark plasma sintering (SPS) at ultra-low temperature (i.e., 1400 degrees C) using very high proportions of MoSi2 aids (i.e., 35-50 vol.%). It is shown that with 40 vol.% MoSi2 aids already sufficient Si transient liquid phase is formed in situ during SPS (by the reaction B4C+2MoSi(2) -> SiC+2MoB(2) + 3Si) to achieve the ultrafast full densification of B4C at 1400 degrees C, the Si melting point, simply by pore filling, particle rearrangement, and liquid spreading. Importantly, it is also shown that the resulting B4C composites are hard (i.e., approximate to 23 GPa) and super wear-resistant (i.e., similar to 10(7) (N.m)/mm(3)), attributes both deriving from the composites' quadruplex-particulate (i.e., B4C plus beta-SiC, beta-MoB2, and MoSi2), fine-grained (i.e., <1 mu m), fully-dense microstructure. Thus, this work opens a new avenue for the present and future lower-cost fabrication of novel B4C composites for use in contact-mechanical and tribological applications. (c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The feasibility of fabricating super wear-resistant hard B4C composites was investigated using spark plasma sintering at an ultra-low temperature with high proportions of MoSi2 aids. The study found that the addition of 40% MoSi2 aids could achieve the ultrafast full densification of B4C at 1400 degrees C, resulting in hard and super wear-resistant composites with a quadruplex-particulate, fine-grained, fully-dense microstructure. This work opens up new possibilities for the low-cost fabrication of novel B4C composites for contact-mechanical and tribological applications.