THERMOMECHANICAL DESIGN CRITERIA FOR CERAMIC-COATED SURFACES.

Finite element modeling of components to determine service and fabrication loads found that inelastic behavior and residual stresses were significant to component life. Inelastic behavior mitigates peak strains but enhances residual strains. Results of furnace, Mach 0. 3 burner, and engine tests are discussed and categorized into design criteria (loading, geometry, fabrication, materials, analysis, and testing). These design rules and finite element analyses are brought to bear on two test cases: turboshaft engine seals and rocket thrust chambers. Nickel aluminide seals were replaced with a 1-mm (0. 040-in. ) thick bond coat and 1-mm-thick ceramic. In the thrust chambers, the requirement of a smooth surface was satisfied by the inside-out process, where the ceramic is plasma sprayed onto a mandrel with the bond coat sprayed onto the ceramic. The system is electroplated with copper, machined, and closed out by electroplating. It can then be wound to mitigate hoop stresses.