Preparation of molybdenum borides by combustion synthesis involving solid-phase displacement reactions

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

“…According to previous studies [15,16], the ejected misty substance is believed to be B 2 O 3 in the form of very fine liquid droplets. B 2 O 3 is the by-product of the displacement reaction of WO 3 with boron.…”

“…However, when direct combustion between the metal and boron is not feasible, the SHS process involving borothermic reduction of metal oxides has been considered as an alternative of preparing the related metal borides [14]. For example, molybdenum borides (Mo 2 B, MoB 2 , and Mo 2 B 5 ) were produced from solid state combustion of the powder compacts composed of MoO 3 , Mo, and boron [15]. Chromium borides (Cr 5 B 3 , CrB, and CrB 2 ) in either monolithic or composite form were fabricated through the SHS process involving reduction of Cr 2 O 3 by boron [16].…”

Preparation and Characterization of MoB Coating on Mo Substrate

“…Consequently, a high temperature (above 900 • C) should be used for the preparation of MoB coating on Mo. The high temperature (above 900 • C) was also required to prepared Mo borides by solid-state reaction [24,25], mechanochemical synthesis [23], and electrochemical synthesis [26]. The backscattered electron (BSE) images of the cross-sectional microstructure of the MoB coating prepared at 1000 °C for 0 h and 5 h are shown in Figure 5.…”

An investigation on the formation mechanism of nano CrB2 powder in the Mg–B2O3–Cr2O3 system

“…Formation of a variety of transition metal diborides MB 2 (M = Nb, Mo, Ta, Ti, Hf, V, and Cr) have been conducted by combustion synthesis from constituent elements in the mode of self-propagation of high temperature (SHS) [9][10][11][12][13]. However, when direct combustion between the metal and boron is not feasible due largely to insufficient exothermicity, the SHS process involving borothermic and boron carbide reductions of chromium oxide has been considered as an alternative for preparing the chromium borides [6][7][8].…”