Accession Number : ADA266460


Title :   Continuous Fabrication of SiC Fiber Tows by Chemical Vapor Deposition


Descriptive Note : Final rept. 1 Sep 1991-31 Dec 1992,


Corporate Author : GEORGIA INST OF TECH ATLANTA


Personal Author(s) : Lackey, W J ; Hanigofsky, J A ; Freeman, G B ; Hardin, R D ; Beckloff, B N ; Emmerich, D M ; Prasad, A ; Ellenburg, M D ; Pugh, J ; Langman, M D ; Lewis, J S


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a266460.pdf


Report Date : Jan 1993


Pagination or Media Count : 106


Abstract : The objective of this 15-month effort was to determine the feasibility of preparing small diameter SiC fiber tows by chemical vapor deposition for use as reinforcing fibers in ceramic and metal matrix composites. The proposed goal of codepositing SiC + Si3N4 was modified 2 months into the project in order to concentrate on fiber coating technology for SiC fiber development only. Our approach was to develop spreading techniques for filaments of the substrate tow so that SiC could be rapidly deposited without bonding the filaments together. Following some initial experiments, a statistical processing study was completed to define processing conditions where the desired 5 micrometers SiC coating thickness would be achieved. Processing-property correlations were determined using multiple regression analysis. Stress calculations were used to aide in substrate selection--the carbon fiber which had the minimal fiber/coating stress due to thermal expansion mismatch was determined to be the Amoco T-300, unsized and untwisted fiber. Several fiber spreading techniques were evaluated to minimize fiber agglomeration. Cyclic tension, in conjunction with gas jets or stationary and moving rollers was determined to be ineffective for spreading the fiber tow. The most promising results, however, were obtained from electromagnetic spreading of the fiber tow.


Descriptors :   *FIBERS , *VAPOR DEPOSITION , *CHEMICAL REACTIONS , *SILICON CARBIDES , STRESSES , ELECTROMAGNETIC FIELDS , CHEMICALS , FIBER REINFORCED COMPOSITES , CARBON FIBERS , REGRESSION ANALYSIS , DEPOSITION , CERAMIC FIBERS , ROLLERS , EXPANSION , FILAMENTS , BONDING , TENSION , STATIONARY , THERMAL EXPANSION , CORRELATION , SILICON NITRIDES , REINFORCING MATERIALS , SELECTION , COATINGS , SUBSTRATES , METAL MATRIX COMPOSITES , FABRICATION , PROCESSING , DIAMETERS , THICKNESS


Subject Categories : Physical Chemistry
      Laminates and Composite Materials
      Textiles


Distribution Statement : APPROVED FOR PUBLIC RELEASE