Synthesis and sintering of TiB2 nanoparticles

Titanium diboride nanoparticles were prepared from TTIP and boron oxide using a sol-gel method followed by mechano-chemical reduction in the presence of aluminum. Optimum weight ratio of B2O3:TTIP:2-propanol was 1:3:60. The XRD results revealed that mechano-chemical reduction of the zerogel by aluminum had led to the formation of TiB2 and Al2O3 phases after 15 hours of milling. The XRD results confirmed complete removal of Al2O3 via leaching the milled sample in 10 M NaOH at 150 °C. SEM and TEM studies showed that the mean particle size of the synthesized TiB2 is less than 30 nm. The densification experiments were carried out using hot pressing and pressureless sintering. The binderless densification of monolithic TiB2 up to 92% theoretical density was achieved by hot pressing at 1700 °C for 2 h in vacuum. The hot pressed TiB2 exhibits high Vickers hardness (25.9 GPa) and relative high fracture toughness (5.7 MPa.m1/2). In the pressureless sintering route, a maximum density of 82.3% ρth is achieved after sintering at 1900 °C for 2 h in vacuum.