Densification, characterization and oxidation studies of novel TiB2+EuB6 compounds

TiB2+EuB6 ceramic samples with different EuB6 contents were fabricated using hot -pressing technique. The introduction of EuB6 promoted the sinterability, fracture toughness and oxidation resistance of TiB2. 98.7% TD achieved by adding 2.5% EuB6 to TiB2 by hot pressing at a relatively low temperature of 1750 degrees C, 35 MPa, 1h. Formation of complete solid solution of TiB2+EuB6 observed for all the samples by XRD, EDS and EBSD. Hardness of all samples is measured in the range of 24-27 GPa similar to 50% higher fracture toughness value of 5.2 MPa m(1/2) was obtained in the 2.5% EuB6 contained sample compared to monolithic TiB2. Enhancement of oxidation resistance of TiB2 was observed by EuB6 addition due to the formation of EuBO3 and Eu2O3. Oxidized cross section of TiB2+EuB6 sample was measured as 340 mm, which is similar to 35% less than that of monolithic TiB2 (520 mm), after oxidation at 1400 degrees C for 8h. (C) 2016 Elsevier B.V. All rights reserved.