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Processing and Properties of TiB 2 with MoSi 2 Sinter‐additive: A First Report
Author(s) -
Murthy T. S. R. Ch.,
Basu B.,
Balasubramaniam R.,
Suri A. K.,
Subramanian C.,
Fotedar R. K.
Publication year - 2006
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2005.00652.x
Subject(s) - sintering , materials science , microstructure , hot pressing , boride , ceramic , vickers hardness test , metallurgy , fracture toughness , pressureless sintering , composite material , phase (matter) , chemistry , organic chemistry
The densification of non‐oxide ceramics like titanium boride (TiB 2 ) has always been a major challenge. The use of metallic binders to obtain a high density in liquid phase‐sintered borides is investigated and reported. However, a non‐metallic sintering additive needs to be used to obtain dense borides for high‐temperature applications. This contribution, for the first time, reports the sintering, microstructure, and properties of TiB 2 materials densified using a MoSi 2 sinter‐additive. The densification experiments were carried out using a hot‐pressing and pressureless sintering route. The binderless densification of monolithic TiB 2 to 98% theoretical density with 2–5 μm grain size was achieved by hot pressing at 1800°C for 1 h in vacuum. The addition of 10–20 wt% MoSi 2 enables us to achieve 97%–99%ρ th in the composites at 1700°C under similar hot‐pressing conditions. The densification mechanism is dominated by liquid‐phase sintering in the presence of TiSi 2 . In the pressureless sintering route, a maximum of 90%ρ th is achieved after sintering at 1900°C for 2 h in an (Ar+H 2 ) atmosphere. The hot‐pressed TiB 2 –10 wt% MoSi 2 composites exhibit high Vickers hardness (∼26–27 GPa) and modest indentation toughness (∼4–5 MPa·m 1/2 ).