Chemical Vapor Composite Materials for Thermal Protection Systems in Aggressive Reentry Space Vehicles

A study of the application of the Chemical Vapor Composites (CVC) process to thermal protection system (TPS) fabrication is proposed. CVC offers the benefits of conventional chemical vapor deposition (CVD) in terms of high material purity and related high temperature performance, but without the high residual stress associated with CVD. The CVC process also allows net shape deposition of complex geometries, thus reducing the costs associated with non-CVC ceramic processing. Trex Enterprises Corporation has developed CVC fabrication technologies for silicon carbide (SiC) components. Trex CVC SiC has demonstrated high temperature performance that is superior to other SiC materials. The proposed Phase I study thus focuses on: 1) the design and modification of a CVC SiC reactor for the manufacture of monolithic TPS components; 2) fabrication of test TPS component items; 3) analysis of the material properties; and 4) theoretical evaluation of the thermal profile of monolithic CVC SiC and ultra-high temperature (UHTC) components under aggressive reentry heating conditions. The potential benefits of the proposed study include improvements of current TPS technologies based on silicon carbide, and a knowledge base that will allow the extension of the CVC process to TPS based on ultrahigh temperature ceramics such as zirconium diboride (ZrB2).