Accession Number : AD0484909

Title :   BORON CARBIDE CONTINUOUS FILAMENTS.

Descriptive Note : Summary technical rept. Jul 64-Jun 65,

Corporate Author : GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV

Personal Author(s) : Gatti, A. ; Cree, R. ; Higgins, J. B. ; Feingold, E.

Report Date : NOV 1965

Pagination or Media Count : 100

Abstract : The potential of boron carbide as a filamentary material for reinforcement of plastic matrices is as great or greater than any material yet considered from the viewpoint of modulus to density ratio. The E/Rho value of 7.15 (in x 10 to the 8th power) for boron carbide is seen to exceed that of boron and silicon carbide, two other materials being studied for similar applications. The ultimate goal of this program is to determine the feasibility of the production of continuous filaments of B4C having a tensile strength of 500,000 psi and possessing the elastic modulus of bulk boron carbide (60-70 x 1000,000 psi). One method of producing B4C filaments, the deposition of B4C from gaseous mixtures of H2, CH4 and BCl3 (dynamic method) was extensively evaluated utilizing a batch process. Filaments were formed on a 1 mil tungsten substrate by this method that exhibited tensile strengths as high as 300,000 psi, with one value of 330,000 psi recorded. Bend strengths of over 3,000,000 psi have also been measured and modulus values of 70 x 1000,000 psi have been obtained. These results are discussed in detail. A second method (pure vapor method) for forming B4C filaments was studied, but discontinued due to practical limitations. Various materials, such as molybdenum, tungsten, iron, stainless steel and silica were studied for use as possible substrate materials. In the batch process which was developed, only .001 in. tungsten was mechanically strong enough to survive deposition temperatures used (1000 C-1200 C).

Descriptors :   (*FILAMENTS, CARBIDES), (*BORON COMPOUNDS, FILAMENTS), SILICON, DENSITY, TENSILE PROPERTIES, STAINLESS STEEL, MOLYBDENUM, IRON, TUNGSTEN, CARBON, HEAT TREATMENT, FEASIBILITY STUDIES, ANNEALING, HYDROGEN PEROXIDE, MECHANICAL PROPERTIES, ETCHING, REINFORCING MATERIALS, PLASTICS, SUBSTRATES.

Subject Categories : Refractory Fibers

Distribution Statement : APPROVED FOR PUBLIC RELEASE