Formation of chromium borides by combustion synthesis involving borothermic and aluminothermic reduction of Cr2O3

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

“…For the Cr-B system, six chromium borides (Cr 2 B, Cr 5 B 3 , CrB, Cr 3 B 4 , CrB 2 , and CrB 4 ) have been reported [3,8]. Among them, CrB 2 is the most stable compound with a melting point of 2200°C [8].…”

“…As an additive, CrB 2 improves sinterability, strength, electrical conductivity and oxidation and corrosion resistance of boron carbide [6,7]. For the Cr-B system, six chromium borides (Cr 2 B, Cr 5 B 3 , CrB, Cr 3 B 4 , CrB 2 , and CrB 4 ) have been reported [3,8]. Among them, CrB 2 is the most stable compound with a melting point of 2200°C [8].…”

“…In this regards, Yeh et al [8] has investigated the incorporation of borothermic and aluminothermic reduction of Cr 2 O 3 into the synthesis reaction of chromium borides. For the case of SHS process and other thermal processes, formation of non-uniform phases and various by-products coupled with grain growth restrict the control of the product morphology and microstructure; hence, it is necessary to find an effective technique that could overcome these disadvantages.…”

“…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]. A few more alternate routes have also been reported in literature.…”

Production of Chromium Boride Layers on Carbon Steel with Conversion Treatment: Chromium Deposition + Diffusion Annealing

“…In the past two decades, borides of transition metals coatings have proven to be one of the most effective materials to increase the service life of machine components, cutting tools and forming tools, especially to improve wear and corrosion resistance [1,2]. Among these metal compounds, chromium boride presents the best chemical and mechanical behavior under severe conditions of use [3,4].…”