Abstract
Despite its attractive properties for applications, including in high-temperature environments, the wide use of TiB-TiB2 ceramics is hindered by its high densification temperature of >1600 °C. Herein, we clarify the effects of Ti-based sintering aids fabricated by mechanical milling on the density and strength of TiB-TiB2 by spark plasma sintering at 1300 °C, corresponding to low-temperature sintering (LTS). The particle and crystallite sizes of the aids are significant parameters for LTS and can be adjusted by mechanical milling, influencing the initial densification behavior. TiB-TiB2 fabricated with 6 wt % of milled Ti aid with particle and crystallite sizes of ∼15 μm and ∼4 nm exhibited 98.9% of the theoretical density and flexural strength of 566.8 ± 170.0 MPa. These values are comparable to those typically fabricated at temperatures >1650 °C. Notably, the TiB generated during sintering enhances the bond strength of the TiB2 grains, resulting in the fracture surface changing from intergranular to transgranular patterns. Hence, the mechanically milled aid improved the mechanical performance of the TiB-TiB2 ceramics through the combined effects of flaw elimination by densification and bond strengthening by TiB formation.
Original language | English |
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Pages (from-to) | 34863-34871 |
Number of pages | 9 |
Journal | Ceramics International |
Volume | 49 |
Issue number | 22 |
DOIs | |
State | Published - Nov 15 2023 |
Externally published | Yes |
Funding
This work was supported by the JSPS Grants-in-Aid for JSPS Fellows [grant number 22J14027 ], the WISE Program for Sustainability in the Dynamic Earth , the GIMRT Proposals of Cooperative Research and Development Center for Advanced Materials [proposal number 202112-CRKEQ-0404 ], and the Joint Usage/Research Program on Zero-Emission Energy Research , Institute of Advanced Energy, Kyoto University [grant number ZE2022A-02 ].
Keywords
- Borides
- Composites
- Milling
- Ultra-high-temperature ceramics