Titanium diboride nano-particles were prepared from TTIP and boron oxide using a sol-gel method followed by mechano-chemical reduction in the presence of Al. Optimum weight ratio of B2O3:TTIP:2-propanol was 1:3:60. The XRD results revealed that mechano-chemical reduction of the zerogel by aluminium had led to formation of TiB2 and Al2O3 phases after 15 hours milling. The XRD results confirmed complete removal of Al2O3 via leaching the milled sample in 10M NaOH at 150ºC. SEM and TEM studies showed that the mean particle size of the synthesized TiB2 is less than 30nm. 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 1700ºC for 2 h in vacuum. The hot pressed TiB2 exhibit 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 1900ºC for 2 h in vacuum.
کلید واژگان :Sol-gel processes; Sintering; Electron microscopy; TiB2
ارزش ریالی : 600000 ریال
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