Accession Number : AD0814712

Title :   DEVELOPMENT OF COMPOSITE STRUCTURES FOR HIGH TEMPERATURE OPERATION.

Descriptive Note : Final rept. 1 Jul 64-28 Feb 67,

Corporate Author : SOLAR TURBINES INTERNATIONAL SAN DIEGO CA

Personal Author(s) : Licciardello, M. R. ; Ohnysty, B.

Report Date : APR 1967

Pagination or Media Count : 182

Abstract : A study was made to determine the usefulness of thoria and hafnia as overlays to protect tungsten or tantalum nose caps for lifting re-entry vehicles. Various composites were evaluated over a temperature range of 3800 to 5300 F. It was determined that overlays required a reinforcement for thermal shock resistance, therefore a tungsten mesh system was selected. The porous nature of the overlays allowed sufficient oxygen to reach the tantalum substrates causing embrittlement or excessive chemical attack, so all tantalum substrates required an additional protective layer. Vapor-deposited tungsten was shown to be suitable up to 4500 F, and a Hf-Ta coating to 3800 F. The most promising system was ThO2 over tungsten, which demonstrated usefulness over several typical re-entry trajectories at temperatures as high as 5300 F. The use of HfO2 must be limited to 4900 F. (Author)

Descriptors :   (*COMPOSITE MATERIALS, HIGH TEMPERATURE), (*REINFORCING MATERIALS, COMPOSITE MATERIALS), NOSE CONES, THERMAL SHOCK, REENTRY VEHICLES, SUBSTRATES, TANTALUM, TANTALUM ALLOYS, TUNGSTEN, TUNGSTEN ALLOYS, THORIUM COMPOUNDS, OXIDES, HAFNIUM COMPOUNDS, THERMAL CONDUCTIVITY, THERMAL EXPANSION, WEIGHT, MELTING POINT, DENSITY, AGING(MATERIALS), SHRINKAGE, OXIDATION, COATINGS, MICROSTRUCTURE.

Subject Categories : Laminates and Composite Materials
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE