Effect of EuB6 addition on densification and properties of ZrB2

Effect of EuB6 addition on densification and properties of ZrB2 have been investigated. Samples of the following composition were hot pressed. (1) ZrB2 + 2.5% EuB6, (2) ZrB2 + 5% EuB6 and (3) ZrB2 + 10% EuB6. EuB6 addition helped in densification of ZrB2 at a lower hot pressing temperature of 1750 °C. Microstructural investigations revealed the formation of ZrB2–EuB6 solid solution. The mode of fracture was seen to be intergranular. Hardness slightly increased with 2.5% EuB6 addition but decreased with 5 and 10% EuB6 addition. Fracture toughness of the composite was better than the monolithic ceramic. Crack deflection and crack branching were observed in the microstructure. The composite samples were found to be resistant to oxidation at 900 °C in air. The nature of oxidation for the composite was near parabolic in nature.

► Effect of EuB6 addition on densification and properties of ZrB2 have been investigated.
► EuB6 lowered the hot pressing temperature to 1750 °C.
► EuB6 addition increased hardness, fracture toughness and oxidation resistance of ZrB2.