Accession Number : AD0882469

Title :   High Viscosity Thermal Protection Materials Summary Report: 1 July 1969-30 June 1970,

Corporate Author : NAVAL ORDNANCE LAB WHITE OAK MD

Personal Author(s) : Wilson, Roger E.

Report Date : 05 MAR 1971

Pagination or Media Count : 44

Abstract : Vacuum hot pressed nozzles of 20 v/o tungsten-80 v/o silica tested in the NOL oxy-hydrogen (H-O) rocket test motor out-performed the best of several ATJ graphite nozzles with a three fold increase in survival time. The ablation resistance varied with density and a minimum of 97% of the theoretical value was needed for satisfactory performance. However, the material performed badly in rocket motor tests using B47 (aluminized) propellant. Excessive throat erosion rate was believed to be caused by the aluminum in the propellant. H-O motor tests of vacuum hot pressed composites in which molybdenum replaced the usual tungsten showed it a poor substitute. A study of the affect of the tungsten-to-silica ratio of a series of hot pressed composites revealed that both strength and elastic moduli increased with increased tungsten content. Substitution of fibrous tungsten for the entire 20 v/o of particulate tungsten in a hot pressed composite produced no increase in mechanical properties although SEM studies revealed wetting of the fibers. Additions of 20 and 50 v/o of graphite fiber to hot pressed silica resulted in a loss in strength of the silica due apparently to a carbon-silica reaction. (Author)

Descriptors :   *COMPOSITE MATERIALS), (*ROCKET NOZZLES, (*SILICON DIOXIDE, COMPOSITE MATERIALS), ABLATION, TEST METHODS, SILICON DIOXIDE, TUNGSTEN, MOLYBDENUM, FIBERS, CARBON FIBERS.

Subject Categories : Laminates and Composite Materials
      Rocket Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE