Effect of heating and purge flow rates on Magnesium Nitridation reaction using Thermogravimetry

Abstract

Magnesium nitride forms when magnesium reacts with nitrogen at high temperatures. This paper analyzes the effect of heating rates and purge flow rates on the magnesium nitridation reaction using Thermogravimetry (TG) equipment. Magnesium nitridation and minuscule oxidation were observed due to reactions with nitrogen and oxygen impurities in the nitrogen gas supply for lower heating rates (LHR) at 8, 10, 12, and 15 K/min. For higher heating rates (HHR) at 20, 22, 25, and 27 K/min, a competing magnesium vaporization reaction was observed after 650 °C. The vaporization reaction results in mass loss, altering the overall chemical kinetics. A decrease in average apparent activation energy values was obtained for higher flow rate experiments. Change in apparent activation energy was related to the compaction and rupture of the nitride and oxide layer. The results of this study provide valuable insights into the magnesium explosion inerting and the selective laser melting (SLM) process.