On the borothermic preparation of some vanadium, niobium and tantalum borides

In situ synthesis of NbB2–NbC composite powders by milling-assisted carbothermal reduction of oxide raw materials

“…Many processes are available for the fabrication of niobium boride or niobium boride-based ceramic powders including high temperature methods using solid state reactions, borothermal and carbothermal reductions [14][15][16][17][18][19][20][21], low-temperature synthesis in an autoclave [22,23], self-propagating high-temperature synthesis (SHS) [3,[24][25][26][27], chemical vapour deposition (CVD) [8] and ball milling and mechanochemical synthesis [28,29]. Borothermal and carbothermal reductions require temperatures above 1600°C to obtain the niobium boride phase if Nb 2 O 5 and B/B 2 O 3 are used as starting materials [14,15,21].…”

“…Borothermal and carbothermal reductions require temperatures above 1600°C to obtain the niobium boride phase if Nb 2 O 5 and B/B 2 O 3 are used as starting materials [14,15,21]. Solid state reactions were carried out using an arc furnace or RF thermal plasma starting from Nb and B elemental powders [16,17,20].…”

Preparation of borides in Nb–B and Cr–B systems by combustion synthesis involving borothermic reduction of Nb2O5 and Cr2O3

“…Yeh). NbB 2 by heating amorphous boron and niobium powders of their equivalent compositions at 1000 • C for 60 min and obtained Nb 3 B 4 under a higher temperature of 1800 • C. According to Iizumi et al [12,13], both CrB and CrB 2 have been synthesized in pure form by milling chromium and boron powders in a planetary ball mill for 20-40 h, followed by annealing at 900-1000 • C. Peshev et al [14,15] performed a series of experiments on the borothermic reduction of metal oxides between 1000 and 1750 • C to prepare the corresponding metal borides, including CrB 2 , Mo 2 B 5 , W 2 B 5 , VB 2 , NbB 2 , and TaB 2 . In addition, Sonber et al [16] fabricated CrB 2 through the reaction of Cr 2 O 3 with boron carbide at 1500-1700 • C in the presence of carbon.…”

“…Many transition metal borides have been fabricated by the solidstate reaction between boron and metal powders [10][11][12][13], and by the reduction of metal oxides with boron [14,15] or boron carbide [16] as the reducing agent. Matsudaira et al [10] produced NbB and * Corresponding author.…”

Preparation of tungsten borides by combustion synthesis involving borothermic reduction of WO3

“…Itoh et al [25] prepared various tungsten borides by solid state reactions between tungsten and boron powers at 800-1550 8C, and indicated that optimum production of WB and W 2 B 5 was attained in the samples with a nearly 10 at.% excess of boron. Peshev et al [26,27] performed a series of experiments on the borothermic reduction of different metal www.elsevier.com/locate/ceramint oxides between 1000 and 1750 8C to prepare the corresponding metal borides, including CrB 2 , Mo 2 B 5 , W 2 B 5 , VB 2 , NbB 2 , and TaB 2 .…”