Phase, microstructure evolution and sintering of Sr-doped TiB₂ precursors

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• 作者：Ľ ; uboš ; Bač ; a^a ; ^{lubos.baca@aac-research.at} ; Zoltá ; n Lenč ; é ; š ; ^b ; Nils Stelzer^a
• 关键词：Borides ; Powders-chemical preparation ; Sol– ; gel processes ; TiB₂
• 刊名：Journal of the European Ceramic Society
• 出版年：2011
• 出版时间：July 2011
• 年：2011
• 卷：31
• 期：8
• 页码：1465-1471
• 全文大小：750 K

文摘

Precursors for the preparation of bulk Sr-doped TiB₂ 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 TiB₂ diffractions and the detection of strontium in TiB₂ grains by EDX analysis the formation of Ti_1 − xSr_xB₂ solid solution is assumed in the Sr-doped powders. Finally, Sr-doped TiB₂ composites were inductive hot-pressed from the as prepared powders at 1900 °C for 7 min. The formation of SrTiO₃ 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.