SBIR-STTR Award

A coating system is proposed comprised of 1. Gradient pigment particles having an iron core encapsulated with a mixed intermetallic-oxide layer and a further silicon-based layer for enhanced bonding to the matrix 2. A matrix raw material that is thermally-sprayable using conventional technology that partially cures to an oxide during application and becomes fully cured on first use 3. Thermal spray equipment with separately-controlled feeders for matrix and pigment feed, to permit application of gradient coatings having superior bond at the interface and maximum pigment content at the surface.

Benefits:
Feature 1: Increase iron content in the coating, as a percentage of total coating weight, by reducing the amount of dielectric-forming elements (e.g. Al, Si) required in the pigment. Benefit 1: Option to improve signature reduction, reduce coating weight, or both Feature 2: The system uses no solvents or liquid carriers. Benefit 2: Application is simplified with no VOC or other vapor discharges to control. Further, system avoids problems associated with coating distortion during bakeout of large liquid fractions, as with slurries. Feature 3: Pigment preparation system utilizes chemical vapor deposition (CVD) of elements onto surface of individual particles, creating ability to formulate unique alloys and gradients at the particle level. Benefit 3: Can quickly screen candidate formulations for improved coupling at high temperature, creating metamaterials that cannot be produced by conventional means. Can optimize the content and location of dielectric layer. Feature 4: Pigment and matrix will be applied by commercially-available thermal spray system, equipped with proposed dual-hopper feeder. System is field-proven, has no moving parts, easily transported and stored, can utilize multiple energy sources. Variant currently in use at multiple NSA manufacturing sites. Can be used in either manual or robotic modes. Benefit 4: Transport and operation require no additions to current infrastructure at repair sites, could be used on emergency basis at any location worldwide. Training has typically been less than 40 hours for equipment use AND repair.

Keywords:
RAM, coating, thermal spray, gradient materials, meta-materials, pigment, low observable, maintainability

A high-temperature composite material and application method have been developed to rapidly repair hot zone LO coatings. The composite material includes RAM filler that has been encapsulated with a durable, oxidation resistant coating. The filler is contained in a silicon oxy-carbide matrix that is rapidly cured, adherent and capable of withstanding thermal and mechanical shock. The matrix represents a significant advance over conventional materials that are based on older, castable refractory technology. Phase II tasks will optimize filler encapsulation, matrix properties and application methods.

Keywords:
Ceramic Matrix Composites, Thermal Spray, Ram, Cor