Efficient Low-Cost Interface Coatings for Three-Dimensional (3-D) Reinforced Ceramic Matrix Composites (CMCs)

Ceramic matrix composites (CMCs) have shown promise for use in hot exhaust structures for turbines in high performance aircraft. However a life limiting failure mode for two types of CMCs with CG Nicalon reinforcement is a tendency to de-laminate during repetitive thermal and mechanical cycling. This behavior is related to low shear strength of the matrix, as there is no cross ply reinforcement in the 2D fiber architecture. The program is aimed at solving a major processing problem that is required to produce 3D architecture composites. The application of low oxygen containing BN-based interface coatings is required to be applied uniformly though out the woven preform. Synterials has developed a method to accomplish the coating process. Three types of fiber architectures will be coated and polymer derived matrix CMCs will be processed, to permit a test bed to determine the utility of 3D reinforcement to improve inter-laminar strengths without severely reducing in-plane tensile properties.