Novel colored flames via chromaticity of essential colors Ramy Sadek, Mohamed Kassem, Mohamed Abdo, Ahmed Fahd, Hesham Tantawy, Amir Elsaidy, Sherif Elbasuney * School of Chemical Engineering, Military Technical College, Kobry El-Kobba, Cairo, Egypt article info Article history: Received 26 March 2018 Received in revised form 1 May 2018 Accepted 6 May 2018 Available online xxx Keywords: Pyrotechnics Colored flame Atomic spectroscopy Molecular spectroscopy Luminous intensity Color quality Chromaticity abstract Colored flame compositions have distinctive variety of applications ranging from military signaling, rocket tracking, and illuminating devices. Certain elements and compounds when heated to high tem- perature are able to emit unique wavelengths in the visible region. This study, reports on the develop- ment of novel colored flames that cannot be generated by emitting atomic/molecular species. This was achieved by using chromaticity of basic colored flames. Mixing of high quality primary colored flames including Blue, Yellow, and Red in proper ratio was conducted; any interfering incandescent emission resulted from MgO was eliminated using Al metal fuel. The spectral characteristics in terms of luminous intensity, and color quality were evaluated using digital luxmeter and UV-Vis. spectrometer respectively. High quality mixed colored flames include violet, sweet pink, and marigold were developed. This study shaded the light on the state of the art for the real development of novel colored flame compositions and chromaticity of basic colored flames. © 2018 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction The production of bright light, with vivid color, is the primary purpose for signaling, projectile tracking, and illuminating systems [1e9]. Certain elements and compounds when heated to high temperature have the unique property of emitting lines or narrow bands in the visible region (380e780 nm) [10e19]. Such elements are called the color source [20,21]. For instance, strontium (red), barium (green), copper (green or blue), and sodium (yellow) [22e27]. Strontium, barium, and copper emit their characteristic color by forming their halides [28,29]; this category of emission is known as molecular emission [30]. Chlorine was found to be an essential element to create different molecular emitting species [24,27]. Chlorine is employed as color intensifier to enhance the production of colored flames in the visible band [7 ,27 ,31]. Without chlorine good colors would be difficult to be developed [27 ,32]. While molecular emission is distinguished by broad band emission; atomic emission is distinguished by sharp discrete wavelength [33,34]. A yellow colored flame can be achieved by atomic emission from stimulated sodium atoms [22]. The production of a vividly colored flame is a challenging problem than creating white light [22]; the development of high quality colored flame requires a delicate balance between different factors including [35e37]: ❖ An atomic or molecular species that will emit the desired wavelength. ❖ The emitting species must be sufficiently volatile to exist in the vapor state. ❖ Sufficient heat should be generated to produce the excited emitter. ❖ The presence of incandescent solid or liquid particles can deteriorate the color quality. Any interfering atomic or molecular emitters must be avoided or at least minimized [38e41]. For instance, magnesium is converted to magnesium oxide (MgO); which is an excellent white light emitter by incandescence [11]. This criteria could adversely affect the color quality [42]. The generation of a mixed colored flame is a big challenge [22]; that requires precise information about the chromaticity as well as high quality colored flames to be mixed together in proper ratio [43]. In color science, The chromaticity diagram describes colors in terms of rectangular x and y coordinates [44]. The white point is a neutral reference characterized by a chromaticity coordinates * Corresponding author. E-mail addresses: s.elbasuney@mtc.edu.eg, sherif_basuney2000@yahoo.com (S. Elbasuney). Peer review under responsibility of China Ordnance Society. Contents lists available at ScienceDirect Defence Technology journal homepage: www.elsevier.com/locate/dt https://doi.org/10.1016/j.dt.2018.05.002 2214-9147/© 2018 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Defence Technology xxx (2018) 1e6 Please cite this article in press as: Sadek R, et al., Novel colored flames via chromaticity of essential colors, Defence Technology (2018), https:// doi.org/10.1016/j.dt.2018.05.002