Temperature dependent hardness and strength properties of TiB2 with TiSi2 sinter-aid

From the perspective of high temperature structural applications, it is important to evaluate temperature dependent mechanical properties of titanium diboride (TiB2) ceramics. The present study reports the effect of TiSi2 content (up to 10 wt.%) and temperature on hardness and strength of TiB2. The hardness properties were measured from room temperature (RT)-900 degrees C in vacuum; the four-point flexural strength properties were evaluated at selected temperatures in air up to 1000 degrees C. An attempt has been made to discuss the difference in hardness and strength properties with sinter-aid amount and microstructure. Our experimental results clearly indicated that the addition of 2.5 wt.% TiSi2 to TiB2 resulted almost full densification at a lower hot pressing temperature of 1650 degrees C without compromising on the high temperature strength and hardness properties. The hot pressed TiB2-2.5 wt.% TiSi2 ceramic could retain moderate strength of more than 400 MPa and hardness of 9 GPa at 1000 degrees C and 900 degrees C, respectively. (C) 2008 Elsevier Ltd. All rights reserved.