Combustion wave propagation mechanism in titanium-boron mixtures

A comparative study on combustion synthesis of Nb–B compounds

“…The preparation of a variety of metal borides, especially the diborides such as TiB 2 , ZrB 2 , HfB 2 , NbB 2 , and TaB 2 , by the SHS technique was demonstrated in a number of investigations [15][16][17][18][19][20][21]. Most of the previous studies [16][17][18][19] focused on the formation of TiB 2 and ZrB 2 . Recently, Przybyl- ski et al [22,23] reported the production of bulk MgB 2 samples (with T c = 37.24 K) by combustion synthesis in the SHS mode.…”

“…Most importantly, the non-equilibrium nature of combustion synthesis gives the opportunity to form metastable or complex phases on account of the steep thermal gradient, high reaction rate, and relatively rapid cooling rate associated with the SHS process [11]. The preparation of a variety of metal borides, especially the diborides such as TiB 2 , ZrB 2 , HfB 2 , NbB 2 , and TaB 2 , by the SHS technique was demonstrated in a number of investigations [15][16][17][18][19][20][21]. Most of the previous studies [16][17][18][19] focused on the formation of TiB 2 and ZrB 2 .…”

Preparation of MoB and MoB–MoSi2 composites by combustion synthesis in SHS mode

“…It is useful to note that the product of nearly single-phase ␣-MoB was yielded from the SHS reaction of the Mo + B powder compact under a preheating temperature between 150 and 400 • C. After SHS reactions, it was found that volume of the assynthesized product expanded slightly, thus resulting in the increase of residual porosity. For the synthesis of MoB, the density of green compacts is 3.07-3.85 g/cm 3 (i.e., 40-50% TD) and the density of as-synthesized products is found in a range of 2.83-3.58 g/cm 3 , which is only about 37-46% of the fully dense MoB (7.7 g/cm 3 ).…”

“…Among the transition metal borides formed by SHS, titanium diboride TiB 2 was the most studied compound [1][2][3][4][5]. Lately, Yeh and Chen [8,9] conducted a comparative study on combustion synthesis of different phases of niobium borides (including Nb 3 B 2 , NbB, Nb 5 B 6 , Nb 3 B 4 and NbB 2 ) from elemental powder compacts with corresponding stoichiometries.…”

“…Preparation of various boride compounds in the Ti-B, Zr-B, Hf-B, Nb-B, and Ta-B systems by self-propagating hightemperature synthesis (SHS) has been demonstrated in a number of investigations [1][2][3][4][5][6][7][8][9][10]. Under the SHS mode of combustion synthesis, metal borides can be produced by the direct reaction of constituent elements or by the reaction of metal oxides with boron [10].…”