US Government As Represented by the Secretary of the Army

USA As Represented by Secretary of the Navy

Charles Stanley Leveritt

Paul J Conroy

John D Demaree

James Hirvonen

James M Garner

Christine Marie Walsh

Christine Dianne Knott

A dynamic process for increasing the wear life of ferrous articles subjected to a high-temperature environment created by combustion of a propellant or fuel comprises selecting the propellant or fuel so that its combustion products include relatively large amounts of nitrogen, which nitrogen forms a protective nitride layer on the surface of the ferrous article. Disclosed is a specific embodiment of the invention for prolonging the wear life of gun barrels.

Dynamic process for enhancing the wear resistance of ferrous articles

A body of iron, steel or other such ferrous material is protected from thermochemical erosion by a layer of an iron nitride having a relatively low nitrogen content. The atomic percentage of nitrogen in the iron nitride layer is no greater than 20%, and in specific embodiments is in the range of 10-15%. The nitride layer may have a layer of a refractory material deposited thereatop. Some refractory materials include metals such as chromium. The invention has specific utility for protecting gun barrels, turbines, internal combustion engines, drilling equipment, machine tools, aerospace systems and chemical reactors which are exposed to extreme conditions of temperature and pressure. Specifically disclosed is a gun barrel which incorporates the invention.

Article with enhanced resistance to thermochemical erosion, and method for its manufacture

The present invention comprises an additive to a propelling charge that greatly reduces barrel erosion when used in a gun system compared to the current additives noted above. The invention provides both a high nitrogen to carbon monoxide ratio in the combustion products of the propelling charge in conjunction with a reduced flame temperature which both work to reduce gun-barrel erosion.

Reduced erosion additive for a propelling charge

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Jarrettsville, MD, United States of America

Charles Stanley Leveritt