Mechanosynthesis of nanocrystalline ZrB₂-based powders by mechanically induced self-sustaining reaction method

Abstract

Preparation of nanocrystalline ZrB₂–based powder by aluminothermic and magnesiothermic reductions in M/ZrO₂/B₂O₃ (M = Al or Mg) systems was investigated. In this research, high energy ball milling was employed to persuade necessary conditions for the occurrence of a mechanically induced self-sustaining reaction (MSR). The course of MSR reactions were recorded by a noticeable pressure rise in the system during milling. Ignition times for ZrB₂ formation by aluminothermic and magnesiothermic reductions were found to be 13 and 6 min, respectively. Zirconium diboride formation mechanism in both systems was explained through the analysis of the relevant sub-reactions.

Keywords:

• Zirconium diboride
• Mechanosynthesis
• Reaction mechanism
• Ball milling

This work was supported by the Spanish government under grant No. MAT2011-22981, which was financed in part by the European Regional Development Fund of 2007–2013. We also acknowledge the Ministry of Science, Research and Technology of Iran for its support of M. Jalaly’s visiting scholarship.