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Synthesis of TaB 2 powders by borothermal reduction
Author(s) -
Guo WeiMing,
Zeng LingYong,
Su GuoKang,
Li Hao,
Lin HuaTay,
Wu ShangHua
Publication year - 2017
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14824
Subject(s) - boron , molar ratio , particle size , materials science , economies of agglomeration , oxygen , nuclear chemistry , particle (ecology) , particle size distribution , chemical engineering , metallurgy , mineralogy , chemistry , catalysis , organic chemistry , oceanography , engineering , geology
Borothermal reduction processes of Ta 2 O 5 with boron under vacuum were investigated. Ta 2 O 5 reacted with boron to form various borides (TaB 2 , Ta 3 B 4 , and TaB), depending on the boron/Ta 2 O 5 molar ratio and temperature. In order to prepare pure TaB 2 powders, two routes were developed. The first route was one‐step heat treatment at 1550°C. With boron/Ta 2 O 5 molar ratio of 9.0, pure TaB 2 powders with strong agglomeration were synthesized by the first route, and the particle size and oxygen content were 0.7 μm and 0.9 wt%, respectively. The second route consisted of two‐step heat treatment at 800°C and 1550°C plus intermediate water washing. With lower boron/Ta 2 O 5 molar ratio of 8.2, pure TaB 2 powders with less agglomeration and more uniform distribution were synthesized by the second route, and the particle size and oxygen content were 0.8 μm and 0.8 wt%, respectively. Moreover, the particle size similarity of TaB 2 powders by the two routes suggested that byproduct boron oxides, which were previously reported as the most important factor in promoting the coarsening of ZrB 2 powders by borothermal reduction, did not lead to the significant coarsening of TaB 2 powders.