Large-scale synthesis of dense Fe3C via ultra-high pressure method

Abstract

In this work, a highly-dense cementite (Fe3C) was synthesized via ultra-high pressure method (UHPM). Different raw batches were prepared under identical synthetic conditions (1000 °C and 4.0 GPa for 10 min). Large amounts of Fe3C were produced from the raw material consisting of ∼ 6 µm iron powder with ∼ 1.5 µm graphite, illustrating that the particle size and carbon source are critical for synthesizing Fe3C via UHPM. The crystal size of the synthesized Fe3C was estimated to be approximately 19 nm by peak broadening of the X-ray diffraction pattern. Additionally, the synthesis of Fe3C was confirmed by electron probe microanalysis analyzer (EPMA) and X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) images showed clearly shaped grain boundaries. The excellent mechanical properties of the prepared Fe3C were confirmed based on an ultrasonic pulse reflecting method. According to the magnetic-hysteresis loop of the Fe3C, it displayed soft ferromagnetic properties.