Accession Number : ADA307287

Title :   Performance of Rocket Nozzle Materials with Several Solid Propellants.

Descriptive Note : Technical note,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Johnston, James R. ; Signorelli, Robert A. ; Freche, John C.

PDF Url : ADA307287

Report Date : MAY 1966

Pagination or Media Count : 28

Abstract : Rocket nozzle throat insert materials were investigated by using three small-scale solid-propellant rocket engines. The materials used included refractory metals, refractory-metal carbides, graphites, ceramics, cermets, and fiber-reinforced plastics. Three propellants with widely differing flame temperatures and oxidation characteristics were used. The flame temperatures were 4700d, 5600, and 6400 F. The engines were designed to provide a chamber pressure of 1000 pounds per square inch and a firing duration of 30 seconds with a nozzle throat diameter of 0.289 inch. No one material performed best with all three propellants. Failure by erosion or cracking occurred with each material with at least one propellant. However, certain classes of materials demonstrated superior performance under specific operating conditions. The fully densified refractory-metal nozzles generally were more resistant to erosion and thermal-stress cracking than the other materials. The graphite nozzles performed well with the least oxidizing 5600 F propellant but generally eroded severely with the other propellants. Some of the refractory-metal carbide nozzles showed outstanding erosion resistance with all three propellants, comparable to that of the best refractory-metal nozzle. However, all of these nozzles cracked as the result of thermal stresses, as did the cermets, silicon nitride, and porous sintered tungsten. Fiber-reinforced plastic nozzles as a class were the least erosion resistant materials.

Descriptors :   *COMPOSITE MATERIALS, *SOLID PROPELLANT ROCKET ENGINES, *ROCKET NOZZLES, DIAMETERS, TEMPERATURE, CRACKS, GRAPHITE, CARBIDES, CERAMIC MATERIALS, OXIDATION, PRESSURE, REFRACTORY METALS, FLAMES, FAILURE(MECHANICS), TUNGSTEN, THERMAL STRESSES, CHAMBERS, NOZZLE THROATS, METAL COMPOUNDS, POROUS MATERIALS, EROSION RESISTANCE, SILICON NITRIDES, SINTERING, CERMETS, REINFORCED PLASTICS.

Subject Categories : Laminates and Composite Materials
      Rocket Engines
      Solid Propellant Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE