Control of carbon loss during synthesis of WC powder through ball milling of WO3–C–2Al mixture

Combination of mechanochemical activation and self-propagating behavior for the synthesis of nanocomposite Al2O3/B4C powder

“…Also, carbothermal reaction (4) is sensitively endothermic thermodynamically, but there is no endothermic peak corresponding to carbothermal reaction in DTA curves. In addition, carbothermal reaction could be achieved at high-temperature; due to diffusional mechanism and low rate of heat conduction, which needs a long time [25]. Based on these results, we can conclude that the carbothermal reaction did not occur during milling process of Al-B 2 O 3 -C system.…”

“…This fact, quick transformation observed by XRD analysis (Fig. 1) and high T ad calculated by thermodynamic relations (Table 3) Some researchers reported that by increasing the milling time, the exothermic aluminothermic reaction provided the required heat for the carbothermic reactions [25,26]. As can be seen, the TG curve does not show any significant change in the sample weight after 200 • C, and this indicated that there is no gas (CO or CO 2 ) emission during the combustion synthesis.…”

An investigation on the mechanochemical behavior of the Ca–C–Cu2O–WO3 quaternary system to synthesize the Cu–WC nanocomposite powder

“…The formation of the W 2 C phase instead of WC is attributed to the following reasons: (i) the high thermodynamic stability of the W 2 C phase at high temperatures resulted from the heat of reduction reactions [24], and (ii) carbon deficiency because of the occurrence of simultaneous reduction reaction of WO 3 and Cu 2 O by carbon, which becomes activated at high temperatures [16]. As explained thoroughly in section (A), the carbothermic reductions of WO 3 and Cu 2 O needed a long time of milling (more than 40 h).…”

Mechanochemical synthesis of tungsten carbide nano particles by using WO3/Zn/C powder mixture

“…This phase can be made instead of WC in high temperatures and low amount of carbon [15]. Some investigations have been done for preventing the production of W 2 C during the milling process [18,19].…”