Enhanced densification of spark plasma sintered TiB2 ceramics with low content AlN additive

Abstract In the present study, we incorporated AlN (5 wt%) with TiB2 ceramic and consolidated the mixture by relatively low temperature sintering method, resulting in a near fully dense composite. Monolithic TiB2 and TiB2–AlN (5 wt%) were manufactured by spark plasma sintering (SPS) at 1900 °C for 7 min under 40 MPa. The prepared composites were precisely characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analyses. In addition, possible chemical reactions during the sintering process were thermodynamically assessed using the HSC Chemistry software. The addition of AlN influenced the sinterability of titanium diboride, yielding a relative density of 99.7%. XRD results revealed the in-situ formation of h-BN during the sintering, whereas thermodynamic studies suggested the formation of both Al2O3 and h-BN. Furthermore, the microstructural investigation verified the synthesis of both Al2O3 and h-BN phases. Finally, the fractographical study revealed the effective role of AlN additive for refining the microstructure of TiB2.