Combustion properties of Mg-based ignition charge using Mg-Gd alloy powder as the fuel

Abstract

The present work aims at improving the combustion properties of Mg-based ignition charge at low ambient pressure. An innovative idea of using the alloy powder of Magnesium-Gadolinium as the fuel in Mg/Teflon/Viton (MTV) has been experimented with. EXPLO5 was initially used to theoretically investigate the combustion properties of MTV under low ambient pressure. The combustion properties of Mg-Gd alloy/Teflon/Viton (MGTV) at pressures of 0.1, 0.07, 0.05, 0.03, and 0.01 MPa were investigated with MTV and Mg-Al alloy/Teflon/Viton (MATV) set as the controls. The radiation properties of MGTV in the open air were studied employing a far-infrared thermal imager, and the heats of combustion and explosion were investigated by a calorimeter. Furthermore, thermogravimetry/differential scanning calorimetry (TG/DSC) was conducted on Mg-Gd alloy and MGTV samples. X-ray diffraction studies were performed on the residue of MGTV after the calcination at 700 and 1000 °C. The results showed that as the fuel, Mg-Gd alloy powder exhibits its best oxidation resistance than Mg and Mg-Al alloy powders. MGTV could stably combust at the pressure of 0.03 MPa, while the controls could only combust stably at 0.05 MPa. The burning rate of MGTV was, respectively, 62 and 25% higher than that of MTV at 0.1 and 0.05 MPa. The flame area, radiation intensity, and radiation energy of MGTV in the open air were, respectively, 68%, 237% and 102% higher than those of MTV and commensurate with MATV. However, the heats of combustion and explosion of MGTV was the least. Further investigation showed that the MGTV could react with O2 at the temperature of 700 °C. The key to improve the burning characteristics was the melting and boiling points of Gd. The combustion mechanism of MGTV was also proposed.