Infrared properties of polycrystalline magnesium fluoride

Heat Flux Measurement from Bulk Magnesium/Teflon/Viton (MTV) Flare Composition Combustion

“…Carbon has a high emissivity at room temperature but this is nearer 0.8 between 1500 and 2400 K [4]. Solid magnesium fluoride is transparent in the IR and is a very poor emitter from 1 to 8 mm [13], even at elevated temperatures. It melts at 1534 K and boils at 2512 K. Koch [11] notes gas phase MgF 2 emitting in the UV but below the boiling point it is likely to be liquid droplets in the fireball and these may also be poor emitters, but will be transparent to the internal radiated heat of the fireball so will not add to self-obscuration.…”

Hot-pressing of bimodally distributed magnesium fluoride powder

“…From the preliminary studies, hot-pressing was found to be so encouraging that an extensive program was carried out in preference to the other methods, each of which was believed to harbor limitations considered more difficult to overcome [5]. Irtran 1 is the commercial name of the first optical polycrystalline magnesium fluoride made in the early 1960s [6].…”

“…Absorption bands correspond to hydroxyl at about 2.8 lm, carbon dioxide at about 4.3 lm, bifluorides at 5 lm, and carbonate at 7 lm wavelengths, as well as the absorption bands at 3.0 and 6.1 lm for moisture. Hot-pressed MgF 2 has some residual water and hydroxide radicals, which are caused by the presence of atmospheric moisture during its fabrication [4,6,8].…”

The dependency of optical properties on density for hot pressed MgF2

“…Transparency, thermal stability and high mechanical strength of these materials are highly influenced by imperfections such as pores and grain boundaries [3][4][5]. Kodak Irtran 1 is the commercial name of the first optical polycrystalline magnesium fluoride made in the early 1960s [6].…”