NxT » Description of the protective coating of the interior of the barrel

With each bullet fired, micro-damages of the inner surface occur inside the barrel, which causes the barrel size (inner diameter) to become larger over time. This wear is the result of the interaction of high-temperature powder gases, the friction of the bullet against the walls, and chemical reactions between the active products of the combustion of the powder and the barrel material. In addition, the loss of protective properties and the increasing degradation of the material structure and barrel geometry lead to disturbances in the projectile motion kinetics and its final destruction. This not only requires frequent maintenance, but is also a source of initiation and accumulation of ballistic errors during the use of the weapon and reduces its accuracy. The inside of the barrel is covered with protective materials, such as chrome, to avoid its wear and change of the assumed design parameters.The basic and most commonly used technology for the protection of the cannon barrel, currently used in weapons, is galvanic chrome plating.

The latest requirements for large-caliber guns are related to their performance, and are related to the latest Mounted Combat System (MCS) mounted on next-generation tanks (Future Combat System (FCS) and the aim of a barrel life of at least 1,500 shots. The current chrome-plated barrel life for the 120 mm tank gun is 280 rounds.The resulting difference in performance requires technology to protect the inside of the barrel, which exceeds the current capabilities of chrome.

Two promising technologies in the production of American weapons. Cylindrical magnetron sputtering (also known as magnetized PVD) Fig. 2 is being developed by the Army for the production of large caliber smoothbore guns. The Navy is also beginning to develop the same technology (with minor modifications) for its rifled barrels for its large-calibre ship-mounted guns.Unlike our technology with a wide range of applications for different diameters and barrel lengths, these technologies have their technical limitations and can only be used for diameters larger than 25 mm.