Cordite

White powder

In 1886, the French chemist Paul Vieille invented the first explosive powder which did not release from smoke (the Poudre B or White Poudre ). It was produced thanks to nitrocellulose and Collodion, mixed with ethanol and ether then mixed to obtain a substance three times more explosive than the blasting powder, without the disadvantages of the latter. The absence of smoke must with a combustion producing a greater proportion of gas than in the case of the blasting powder. This one is degraded with 60 % in solid products of which Sulfate and Carbonate of Potassium.

The French Army adopted this explosive immediately, but it was unstable and was the cause of several accidents. Two ships, the Iéna and the Liberté exploded with Toulon in 1907 and 1911.

Alfred Nobel invented in 1887 a similar explosive: the Ballistite. It was composed with 10 % of Camphor, 45 % of nitroglycerin and 45 % of collodion. In the patent deposited by Nobel, it is question of a nitrocellulose which must be " well-known soluble" type;. With time, camphor evaporated and the explosive became unstable.

Evolution of ballistite

An group of expert with the the United Kingdom, the Explosive Committee directed by Sir Frederick Abel, was interested in the development abroad as regards explosives. Abel and another member, Sir James Dewar, patented in 1889 a new made up mixture with 58 % of nitroglycerin, 37 % of nitrocellulose and 5 % of petroleum jello. With acetone acting as solvent, the paste was extruded in the form of cords called cords of powder or modification of ballistite by the Committee . A little later these denominations were replaced by cordite . The chemists discovered whereas the speed of combusion depended on the diameter and surface exposed on the cord on explosive. Fine cords were intended for small weapons and burned quickly whereas the cords of a higher diameter spent more time to be consumed and were used out of artillery.

Nobel attacked Abel and Dewer about his patent but it lost its lawsuit in 1895 because it had specified a soluble and nonsolid nitrocellulose as in the case of cordite.

Improvements of cordite

The three explosives continued to be used by the various armies during several years but cordite became gradually the explosive of choice. The first versions of cordite were corrosive and attacked the artillery guns. The British changed the composition with 65 % of nitrocellulose, 30 % of nitroglycerin and 5 % of petroleum jello after the second war against the Boers. This version was named cordite MANDELEVIUM ( MoDified ).

During the First World War, the reserves of acetone became exhausted quickly and the British developed a new formula. It was cordite RDB ( Research Department formulated B ) with 52 % of collodion, 42 % of nitroglycerin and 6 % of petroleum jello. This alternative was unstable and was replaced by the old formula as soon as acetone was again available. Research to decrease the quantity of solvents necessary and to improve the stability of the mixture was led and led to the version which was used during the Second world war, the cordite NR .

Cordite NR contains an additional ingredient, the nitroguanidine which produces large quantié of Azote during combustion what reduces the intensity of the flash on the outlet side of the gun. Its temperature of lower combustion reduced also the erosion of the guns, in particular those of the navy.

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