Smokeless powder 860000 219420261 2008-06-15T03:40:57Z SieBot 4005189 robot Adding: [[he:אבק שריפה נטול עשן]] {{Refimprove|date=June 2007}} [[Image:N110 ruuti.jpg|thumb|250px|Smokeless powder]] '''Smokeless powder''' is the name given to a number of [[propellant]]s used in [[firearm]]s and [[artillery]] which produce negligible smoke when fired, unlike the older [[Gunpowder]] (black powder) which they replaced. Types of smokeless powder include [[Cordite]], [[Ballistite]] and, historically, [[Poudre B]]. They are classified as '''single-base''', '''double-base''' or '''triple-base''' powders. ==Description== Smokeless powder consists of [[nitrocellulose]] ('''single-base powders'''), frequently combined with up to 50 percent [[nitroglycerin]] ('''double-base powders'''), and sometimes nitroglycerin and [[nitroguanidine]] ('''triple-base'''), corned into small spherical balls or [[extrusion|extruded]] into cylinders or flakes using solvents such as [[diethyl ether|ether]]. Other minor ingredients, such as stabilizers and ballistic modifiers, are also added. Double-base propellants are common in handgun and rifle ammunition. Triple-base propellants are more common in artillery guns. The reason that they are smokeless is that the [[combustion]] products are mainly [[gas]]eous, compared to around 55% solid products for black powder ([[potassium carbonate]], [[potassium sulfate]] etc). Smokeless powder burns only on the surfaces of the granules, flakes or cylinders - described as ''granules'' for short. Larger granules burn more slowly, and the burn rate is further controlled by flame-deterrent coatings which retard burning slightly. The intent is to regulate the burn rate so that a more or less constant pressure is exerted on the propelled projectile as long as it is in the barrel so as to obtain the highest velocity. [[Cannon]] powder has the largest granules, up to thumb-sized cylinders with seven perforations (one central and the other six in a circle halfway to the outside of the cylinder's end faces). The perforations stabilize the burn rate because as the outside burns inward (thus shrinking the burning surface area) the inside is burning outward (thus increasing the burning surface area, but faster, so as to fill up the increasing volume of barrel presented by the departing projectile). Fast-burning [[pistol]] powders are made by extruding shapes with more area such as flakes or by flattening the spherical granules. Drying is usually performed under a vacuum. The solvents are condensed and recycled. The granules are also coated with [[graphite]] to prevent static electricity sparks from causing undesired ignitions. ==History== Military commanders had been complaining since the [[Napoleonic Wars]] about the problems of giving orders on a battlefield that was covered in thick smoke from the [[gunpowder]] used by the guns. A major step forward was introduced when [[guncotton]], a [[nitrocellulose]]-based material, was first introduced by [[Christian Friedrich Schönbein]] in 1846. He also promoted its use as a blasting explosive. Guncotton was more powerful than gunpowder, but at the same time was somewhat more unstable. This made it unsuitable as a propellant for small firearms: not only was it dangerous under field conditions, but guns that could fire thousands of rounds using gunpowder would be "used up" after only a few hundred with the more powerful guncotton. It did find wide use with artillery. However, within a short time there were a number of massive explosions and fatalities in guncotton factories due to lack of appreciation of its sensitivity and the means of stabilization. Guncotton then went out of use for some twenty years or more until it could be tamed; it was not until the 1880s that it became a viable propellant. In 1884 [[Paul Vieille]] invented a smokeless gunpowder called [[Poudre B]], made from gelatinized guncotton mixed with [[diethyl ether|ether]] and [[ethanol|alcohol]]. It was passed through rollers to form thin sheets, which were cut into flakes of the desired size. The resulting [[propellant]], today known as '''pyrocellulose''', contains somewhat less [[nitrogen]] than guncotton and is less volatile. A particularly good feature of the propellant is that it will not detonate unless it is compressed, making it very safe to handle under normal conditions. Vieille's powder revolutionized the effectiveness of small guns, for several reasons. First, it gave off almost no smoke. After a few shots, a soldier with black powder ammunition would have his view obscured by a huge pall of smoke unless there was a strong wind. Conversely, a [[sniper]] or other hidden shooter would not be given away by a cloud of smoke over the firing position. Further, it was three times more powerful than black powder, which gave more power from less powder. The higher [[muzzle velocity]] meant a flatter [[trajectory]] and therefore more accurate long range fire, out to perhaps 1000 metres in the first smokeless powder rifles. Since less powder was needed to propel a bullet, the [[cartridge (firearms)|cartridge]] could be made smaller and lighter. This allowed troops to carry more ammunition for the same weight. Also, it would burn even when wet. Black powder ammunition had to be kept dry and was almost always stored and transported in watertight cartridges. Vielle's powder was used in the [[Lebel rifle]] that was immediately introduced by the [[Military of France|French Army]] to exploit its huge benefits over black powder. Other European countries swiftly followed and started using their own versions of Poudre B, the first being [[Germany]] and [[Austria]] which introduced new weapons in 1888. Meanwhile, in [[Great Britain]], in 1887, [[Alfred Nobel]] developed a smokeless gunpowder called [[Ballistite]]. A modified form of this was devised by Sir [[Frederick Abel]] and [[James Dewar]] which eventually became known as [[Cordite]], leading to a lengthy court battle between Nobel and the other two inventors over alleged British [[patent]] infringement. In the [[USA]], in 1890, a patent for smokeless powder was obtained by [[Hudson Maxim]]. These newer propellants were more stable and thus safer to handle than Poudre B, and also more powerful. Today, propellants based on nitrocellulose alone are known as '''single-base''', whereas cordite-like mixtures are known as '''double-base'''. A '''triple-base''' flashless cordite was also developed, primarily for large [[naval artillery|naval guns]], but also used in battle [[tank]] ammunition. Smokeless powder allowed the development of modern semi- and fully automatic firearms. Burnt blackpowder leaves a thick, heavy fouling which is both [[hygroscopic]] and [[corrosive]]. Smokeless powder fouling exhibits none of these properties. This makes an autoloading firearm with many moving parts feasible (which would jam or seize under heavy blackpowder fouling). Single and double-base smokeless powders now make up the vast majority of propellants used in firearms. They are so common that most modern references to "gunpowder" refer to a smokeless powder, particularly when referring to [[small arms]] ammunition. ==Instability and stabilization== Nitrocellulose deteriorates with time, yielding acidic byproducts. Those byproducts catalyze the further deterioration, increasing its rate. The released heat, in case of bulk storage of the powder, or too large blocks of solid propellant, can cause self-ignition of the material. Single-base nitrocellulose propellants are most susceptible to degradation; double-base and triple-base propellants tend to deteriorate more slowly. To neutralize the decomposition products, which could otherwise cause corrosion of metals of the cartridges and gun barrels, [[calcium carbonate]] is added to some formulations. To prevent buildup of the deterioration products, [[stabilizer (chemistry)|stabilizers]] are added. [[2-Nitrodiphenylamine]] is one of the most common stabilizers used. Others are [[4-nitrodiphenylamine]], [[N-nitrosodiphenylamine]], [[N-methyl-p-nitroaniline]], and [[diphenylamine]]. The stabilizers are added in the amount of 0.5-2% of the total amount of the formulation; higher amounts tend to degrade its ballistic properties. The amount of the stabilizer is depleted with time. Propellants in storage should be periodically tested on the remaining amount of stabilizer, as its depletion may lead to autoignition of the propellant. ==Smokeless propellant components== The propellant formulations may contain various energetic and auxiliary components: * Propellants: ** [[Nitrocellulose]], an energetic component of most smokeless propellants ** [[Nitroglycerin]], an energetic component of double-base and triple-base formulations ** [[Nitroguanidine]], a component of triple-base formulations * [[Plasticizer]]s, to make the grains less brittle ** [[Dibutyl phthalate]] ** [[Polyester adipate]] ** [[Dinitrotoluene]] (toxic, carcinogen, obsoleted) * [[Binder (material)|Binders]], to hold the grain shape ** [[Rosin]] ** [[Ethyl acetate]] * [[stabilizer (chemistry)|Stabilizers]], to prevent or slow down self-decomposition ** [[Diphenylamine]] ** [[2-Nitrodiphenylamine]] ** [[4-nitrodiphenylamine]] ** [[N-nitrosodiphenylamine]] ** [[N-methyl-p-nitroaniline]] * [[Decoppering]] additives, to hinder the buildup of copper residues from the gun barrel rifling ** [[Tin]] metal and compounds, e.g. [[tin dioxide]] ** [[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 ** [[Lead]] foil and lead compounds, phased out due to toxicity * Flash reducers, to reduce the brightness of the [[muzzle flash]] ** [[Potassium nitrate]] ** [[Potassium sulfate]] (both have a disadvantage - production of smoke) * Wear reduction additives, to lower the wear of the gun barrel liners [http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm USA 16"/50 (40.6 cm) Mark 7] ** [[Wax]] ** [[Talc]] ** [[Titanium dioxide]] ** [[Polyurethane]] jackets over the powder bags, in large guns * Other additives ** [[Graphite]], a [[lubricant]] to cover the grains and prevent them from sticking together, and to dissipate [[static electricity]] ** [[Calcium carbonate]], to neutralize acidic decomposition products The properties of the propellant are greatly influenced by the size and shape of its grains. The surface of the grains influences the speed of burning, and the shape influences the surface and its change during burning. By selection of the grain shape it is possible to influence the pressure vs time curve as the propellant burns. Faster-burning propellants generate higher temperatures and higher pressures, however they also increase the wear of the gun barrels. A Primex powder contains 0-40% nitroglycerin, 0-10% dibutyl phthalate, 0-10% polyester adipate, 0-5% rosin, 0-5% ethyl acetate, 0.3-1.5% diphenylamine, 0-1.5% N-nitrosodiphenylamine, 0-1.5% 2-nitrodiphenylamine, 0-1.5% potassium nitrate, 0-1.5% potassium sulfate, 0-1.5% tin dioxide, 0.02-1% graphite, 0-1% calcium carbonate, and nitrocellulose as the remainder to 100%. [http://www.reloadbench.com/gloss/msds1.txt USA smokeless powder manufacturer's Material Safety Data Sheet] ==References== <div class="references-small"> <!--See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for an explanation of how to generate footnotes using the <ref(erences/)> tags--> <references/> </div> ==See also== *[[Antique guns]] *[[Black powder]] *[[Ballistite]] *[[Cordite]] *[[Firearms]] *[[Nitrocellulose]] *[[Small arms]] ==External links== * '''{{US patent|430212}}''' - ''Manufacture of explosive'' -- H. S. Maxim * [http://www.fbi.gov/hq/lab/fsc/backissu/april2002/mccord.htm The Manufacture of Smokeless Powders and their Forensic Analysis: A Brief Review] - Robert M. Heramb, Bruce R. 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