Smokeless powder

Smokeless powder is the name given to a number of propellants used in firearms and artillery which produce negligible smoke when fired, unlike the older gunpowder (black powder) which they replaced. The basis of the term smokeless is that the combustion products are mainly gaseous, compared to around 55% solid products (mostly potassium carbonate, potassium sulfate, and potassium sulfide) for black powder.[1] Despite its name, smokeless powder is not completely smoke-free[2] and does not take the form of a true powder (see granular material). Smokeless powder allowed the development of modern semi- and fully automatic firearms. Burnt black powder leaves a thick, heavy fouling which is hygroscopic and which causes the rusting of the barrel. Smokeless powder fouling exhibits none of these properties. Smokeless propellant components The propellant formulations may contain various energetic and auxiliary components: * Propellants: o Nitrocellulose, an energetic component of most smokeless propellants[12] o Nitroglycerin, an energetic component of double-base and triple-base formulations[12] o Nitroguanidine, a component of triple-base formulations[12] o D1NA (bis-nitroxyethylnitramine)[13] o Fivonite (tetramethylolcyclopentanone)[13] o DGN (di-ethylene glycol dinitrate)[14] o Acetyl cellulose[15] * Deterrents, (or moderants), to slow the burning rate o Centralites (symmetrical diphenyl urea -- primarily diethyl or dimethyl)[16][17] o Dibutyl phthalate[12][17] o Dinitrotoluene (toxic, carcinogenic, and obsolete)[12][18] o Akardite (asymmetrical diphenyl urea)[14] o ortho-tolyl urethane[19] o Polyester adipate o Camphor (obsolete)[17] * Stabilizers, to prevent or slow down self-decomposition[20] o Diphenylamine[21] o Petroleum jelly[22] o Calcium carbonate[12] o Magnesium oxide[14] o Sodium bicarbonate[15] o beta-naphthol methyl ether[19] o Amyl alcohol (obsolete)[23] o Aniline (obsolete)[24] * Decoppering additives, to hinder the buildup of copper residues from the gun barrel rifling o Tin metal and compounds (e.g., tin dioxide)[12][25] o Bismuth metal and compounds (e.g., bismuth trioxide, bismuth subcarbonate, bismuth nitrate, bismuth antimonide); the bismuth compounds are favored as copper dissolves in molten bismuth, forming brittle and easily removable alloy o Lead foil and lead compounds, phased out due to toxicity[13] * Flash reducers, to reduce the brightness of the muzzle flash (all have a disadvantage: the production of smoke)[26] o Potassium chloride[27] o Potassium nitrate o Potassium sulfate[12][25] o Potassium hydrogen tartarate (a byproduct of wine production formerly used by French artillery)[27] * Wear reduction additives, to lower the wear of the gun barrel liners[28] o Wax o Talc o Titanium dioxide o Polyurethane jackets over the powder bags, in large guns * Other additives o Ethyl acetate, a solvent for manufacture of spherical powder[22] o Rosin, a surfactant to hold the grain shape of spherical powder o Graphite, a lubricant to cover the grains and prevent them from sticking together, and to dissipate static electricity[11]