Phase, microstructure evolution and sintering of Sr-doped TiB 2 precursors

• Published in: Journal of the European Ceramic Society Vol. 31; no. 8; pp. 1465 - 1471
• Main Authors: Bača, Ľuboš, Lenčéš, Zoltán, Stelzer, Nils
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2011
• Subjects: Borides; Powders-chemical preparation; Sol–gel processes; TiB 2; Borides; Sol–gel processes; Powders-chemical preparation; TiB 2
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2011.02.028

Precursors for the preparation of bulk Sr-doped TiB 2 composites were synthesized by modified Pechini method. The high temperature behaviour of homogeneous Sr–Ti–B–C–O gels was investigated in the range 1200–1650 °C. DTA-TG analysis of the precursor powder shows two steps of the carbothermal reduction with endothermic peaks at temperatures of 1335 °C and 1500 °C. The influence of strontium content (2, 5, 10, 20 and 50 mol.%) on the phase composition and morphology of powders at 1650 °C was studied. Due to the shift of TiB 2 diffractions and the detection of strontium in TiB 2 grains by EDX analysis the formation of Ti 1 − x Sr x B 2 solid solution is assumed in the Sr-doped powders. Finally, Sr-doped TiB 2 composites were inductive hot-pressed from the as prepared powders at 1900 °C for 7 min. The formation of SrTiO 3 phase in the powders is serving as a sintering aid during the preparation of bulk Sr–Ti–B composites. The exaggerated grain growth (grain size up to ∼60 μm) occurs during the sintering with increasing content of strontium in the precursor.