The Flame Emission of Indium from a Pyrotechnical View

Abstract

Until today, all blue‐colored light‐generating pyrotechnics are still based on copper and a halogen‐source providing the blue‐emitting species copper(I) chloride, copper(I) bromide or copper(I) iodide. The use of indium as a potential halogen‐free blue light emitter in modern pyrotechnics is described. Therefore, metallic indium was introduced as both fuel and colorant in various pyrotechnical formulations including guanidine nitrate or potassium nitrate as oxidizing agent as well as magnesium, hexamethylentetramine and 5‐amino‐1H‐tetrazole as fuel. The effect of incandescence was examined by applying different magnesium contents within the mixtures. Emission spectra and occurring emission lines of indium‐based pyrotechnical compositions were recorded and evaluated for the first time. Since the expected blue flame color could not be completely achieved, the emission of indium was discussed from an academic point of view.

An Experimental Comparison of Selected Blue Flame Pyrotechnics

“…Recently, the flame color of pyrotechnics containing metallic indium has been investigated. These results do not indicate that indium is, even from a purely technical point of view, a viable alternative emitter [15].…”

Top Development of Green-Light Pyrotechnics: Hypergolic Cu(II)-Based Coordination Polymers

“…Fireworks with different colors and brightness are prepared by changing the types and proportions of oxidants and colorants. 5,6 However, there are many unavoidable disadvantages of traditional pyrotechnics. (1) Physical mixing methods do not ensure that all components are in uniform and intimate contact.…”

“…8 (5) To increase the combustion temperature, nano-Al is an indispensable role, but it is a dangerous element. (6) Chlorine donors (poly(vinyl chloride), PVC) are important because metal chlorides are the main source of color, but these chlorine donors are highly carcinogenic during combustion. 9 Therefore, we need to explore a new material to avoid the above fatal flaws of pyrotechnics.…”

Color‐Changing Sparks from Rare Earth Metal Powders

“…Consequently, even elements with higher boiling points than erbium may provide element-specifically emitting stages. Jennings-White gives a survey on potential candidates for pyrotechnic applications throughout the periodic Table [12] and recent examples include boron, [13][14][15] cesium compounds, [16,17] copper iodide [18] and copper complexes [19] as well as copper-based blue strobe compositions, [20,21] new formulations based on lithium, [22,23] and sodium salts, [24] detailed investigations of composition based on barium [25] and strontium [26] salts as well as calcium [27] and strontium tetrazolates, [28] and indium [29] metal. Typical radiation trace of sparks based on different burning stages given in literature [11] and element-specific colored stage observed for erbium.…”