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

作者：Torabi Omid^*; Golabgir Mohammad Hossein; Tajizadegan Hamid

来源：International Journal of Refractory Metals and Hard Materials, 2015, 51: 50-55.

DOI：10.1016/j.ijrmhm.2015.02.015

• Ceramics
• Powder metallurgy
• Differential thermal analysis (DTA)
• Nanostructures

Fundamental aspects of reaction path in the Cr2O3 + B2O3 + Mg system to synthesize chromium diboride have been investigated. Phase transformation analysis and structural evaluation were carried out by means of differential thermal analysis techniques (DTA), X-ray diffractometry, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to DTA results, the magnesiothermic reductions of B2O3 and Cr2O3 incompletely occurred after the magnesium melting (830 and 1100 degrees C). The products obtained from the thermal synthesis consisted of MgO, Cr and the remaining starting materials, while, no chromium diboride phase achieved even up to 1300 degrees C. Single phase chromium diboride (CrB2) powder was in situ synthesized in selfsustaining mode by mechanochemical method with an ignition time of approximately 2.5 h. The reaction mechanism in this system was determined by studying the relevant sub-reactions. SEM and TEM observations confirmed that the range of particle size was within 100 nm.

• 出版日期2015-7