NOVEL STRAIN TOLERANT COATING MATERIALS AND ARCHITECTURES MANUFACTURED BY AIR PLASMA SPRAY

In the last decade the fields of strategic, theatre, and tactical defense have witnessed significant transitions and advancements with a focus on developing glide vehicles and interceptors that can travel at hypersonic speeds (HGVs and GPIs) along with conventional reentry vehicles (RVs). Advanced areas of hypersonic vehicle development have begun to pursue concepts such as the use of shape morphing outer mold line and control surfaces, which seek to create seamless control surfaces to replace hinged ailerons and flaps. Such concepts push the boundaries of materials and engineering providing significant challenges to the rigid thermal protection systems currently used in these applications. As such a multifunctional highly strain tolerant oxidation and thermal protection coating is proposed utilizing multilayer design and Air Plasma Spray (APS) manufacturing. As structural materials are expected to come in the from of both metallic alloys and carbon composites, two families of materials systems are proposed. For metallic alloys oxidation protection will come from a thin alumina scale forming MCrAlY with a thick highly compliant insulating ceramic overlay coating generated through novel coating design and manufacturing. A similar multilayer strategy will be utilized for carbon composites with oxidation protection coming from high temperature refractory materials-based layer, again with additional insulation in the form of a highly compliant insulating top layer. Additional intrinsic and extrinsic pathways for enhanced strain tolerance of the insulating top layer will be pursued. Intrinsic mechanisms will come from process induced segmentation of the insulating top layer while extrinsic mechanisms will be pursued through the formation of large strain tolerant architectures imparted by surface features though novel additive assembly of layered structures. Approved for Public Release | 24-MDA-11906 (16 Sep 24)