Mechanosynthesis of β-Cr2N using BN as the nitrogen source

Abstract

The mechanosynthesis of hexagonal chromium nitride (β-Cr2N) is explored by the high-energy ball-milling of Cr and h-BN. The β-Cr2N onset formation is observed after 20 min of milling, although the complete reaction is achieved at 100 min of milling. Two different 1Cr:1BN and 2Cr:1BN molar ratios were evaluated, observing that the molar ratio plays an essential role in the end products during mechanosynthesis. The products were characterized by XRD, FTIR and Raman spectroscopy, thermal analysis (TGA and DSC), SEM, and surface area (BET). A preliminary phase stability map vs. accumulative energy (ΔEvaccum) has been constructed. The accumulative energy needed for the complete β-Cr2N formation is ΔEvaccum > 720 kJ/g.