Joining B4C–TiB2 ceramics with Ti interlayer via spark plasma sintering: Temperature-dependent interfacial microstructure and mechanical strength

B₄C–TiB₂ has established itself as a prominent structural and functional integrated material, owing to its remarkable synergy of robust mechanical properties with high electrical conductivity and excellent specific electromagnetic interference shielding performance. The integration of multiple functions is certain to create more opportunities for the application of B₄C–TiB₂ ceramic in various fields. However, in practical engineering applications, ceramic materials often need to be made into larger or more complex components. This makes it extremely important to develop reliable ways to join B₄C–TiB₂ ceramics. Even though B₄C–TiB₂ ceramic shows great potential, there is very little research on how to join it.

Recently, Songlin Ran et al. from Anhui University of Technology, China reported the joining of B₄C–TiB₂ composite ceramics by spark plasma sintering (SPS) with Ti foil as an intermediate layer. Both B₄C–TiB₂ composites and Ti have high conductivity, which is beneficial to current passing through and effectively accelerates interfacial mass transfer and bonding during SPS bonding.

The team published their work in Journal of Advanced Ceramics on June 10, 2025.

“In this report, we investigated the SPS joining of B₄C–40 vol% TiB₂ ceramics using a Ti foil interlayer within the temperature range of 1000–1400 ℃. The competitive reactions between active Ti and ceramic phases drove a sequential compositional evolution at the joint interface: starting from pure Ti, the interface transitioned to a mixture of TiB₂, TiC, TiB, and residual Ti, ultimately forming a stable TiB₂–TiC–TiB ceramic assemblage as temperature increased.” said Songlin Ran, professor at School of Materials Science and Engineering at Anhui University of Technology (China), a senior expert whose research interests focus on the field of functionalized structural ceramics.

Temperature significantly influenced the reaction layer thickness. Between 1000–1300 °C, the reaction layer thickness increased gradually from 3.26 μm to 13.78 μm and showed direct correlation with temperature via Arrhenius-type kinetics. The activation energy (Q) for the interface reaction was calculated to be 263 kJ/mol, and the growth constant (k₀) was 1.98 × 10² mm²/s. Phase evolution at the interface was divided into four stages: initial physical contact, heating and diffusion, isothermal phase transformation, and joint formation. “Ti can react with B₄C and TiB₂ to form high-melting-point ceramic phases, such as TiB₂, TiB, and TiC. Both B₄C–TiB₂ composite and Ti are highly conductive, which facilitates current passage and effectively accelerates interfacial mass transfer and bonding during SPS joining process.” said Songlin Ran.

The shear strength increased from 10 MPa at 1000 °C to 72 MPa at 1300 °C before decreasing to 53 MPa at 1400 °C, reflecting a temperature-driven, thickness-governed strengthening mechanism. Fracture analysis of the joint with the highest shear strength at 1300 °C showed that crack propagation occurred through the ceramic matrix, reaction layer, and residual Ti layer, exhibiting typical cross-layer fracture characteristics that validated strong interfacial bonding. “Reliable bonding of B₄C–40 vol% TiB₂ ceramics using a Ti interlayer can be achieved by optimizing the SPS temperature. These findings provide valuable guidance for broadening the practical engineering application of this material.” said Songlin Ran.

However, more detailed research works are still needed to further explore the behavior and characteristics of B₄C–TiB₂ ceramics in pulsed electric field assisted joining. Ran pointed out the main directions of future research, including the design and optimization of the composite interlayer, the feasibility analysis of the direct connection method, the systematic study of the connection mechanism, the characterization of the microscopic mechanical properties of the joint, and the in-depth analysis of the fracture mechanism.

Other contributors include Wei Wang, Xing Jin，Lei Zhao, Yaxin Wang from the School of Materials Science and Engineering at Anhui University of Technology in Mananshan, China; Ao Han, Gang Wang from the School of Materials Science and Engineering at Anhui Polytechnic University in Wuhu, China.

This work was supported by the National Natural Science Foundation of China (Nos. 52472061, 52171148 and 52072003), and the Natural Science Foundation of Anhui Provincial Education Department (Nos. 2024AH040031 and 2023AH052703).

About Author

Dr. Songlin Ran earned his Ph.D. from Shanghai Institute of Ceramics, Chinese Academy of Sciences. From 2008 to 2010, he conducted postdoctoral research at KULeuven (University of Leuven, Belgium). He is currently a professor at the School of Materials Science and Engineering, Anhui University of Technology in Ma’anshan, China.

His main research areas include functionalization of structural ceramics, and comprehensive utilization of solid waste. He has published over 70 SCI papers as the first or corresponding author. His innovative work has resulted in 13 Chinese invention patents 1 US invention patent. Currently, he serves as an assistant editor for Journal of Advanced Ceramics, a young editorial board member for Journal of Ceramic and Rare Metals. His contributions have been recognized with the Outstanding Journal Reviewer award from The American Ceramic Society journal and the Outstanding Contribution in Reviewing award from the Ceramics International journal.

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen. JAC’s 2023 IF is 18.6, ranking in Top 1 (1/31, Q1) among all journals in “Materials Science, Ceramics” category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508