TECHNICAL POINT OF CONTACT (TPOC)
Colin Ryan
PROJECTED CMMC LEVEL REQUIREMENT
Level 1
TECHNOLOGY AREAS
Air Platform
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Materials
MODERNIZATION PRIORITIES
Hypersonics
KEYWORDS
composite ceramic; infrared transparent; nanoscale microstructure; ceramic scale-up; IR window; nanocomposite; thermal stability; thermal shock resistance
OBJECTIVE
The objective of this topic is to spur research into industrially scalable production methods for an IR-transparent composite ceramic exhibiting sub-100 nm microstructural features in all phases on samples larger than 2" x 4" x 0.5", porosity below 0.1%, microstructural and optical stability to 1200 degrees C, and a thermal expansion to thermal conductivity ratio (alpha/k) at or below 1.0 micrometers/W at 1000 degrees C.
ITAR
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
DESCRIPTION
The Navy has demonstrated within its laboratories that a composite ceramic exhibiting IR transparency can be produced with distinct phases, microstructural feature sizes below 100 nm in all phases, and porosity content below 0.1% on component parts as large as 0.4 inch in lateral dimension. Phase identity, crystal structure, phase chemistry, microstructure feature size, and porosity content were established via X-ray diffraction (XRD) and scanning electron microscopy (SEM) cross-sections with energy dispersive spectroscopy (EDS) analysis. Retention of sub-100 nm feature sizes across all phases is critical to achieving the desired mechanical and thermal properties of the composite; porosity above 0.1% similarly degrades mechanical performance. All three specifications -- sub-100 nm microstructural features in all phases, porosity below 0.1%, and Short-Wave to Mid-Wave Infrared (SWIR/MWIR) transparency of at least 80% -- must be achieved at scale for the material to be suitable for transition.
Producing IR-transparent composite ceramics meeting these specifications at sample sizes relevant to aperture applications is a significant technical challenge. Conventional ceramic processing routes that rely on mechanical mixing or co-precipitation of constituent phases typically result in microstructural coarsening during densification that precludes achieving sub-100 nm feature sizes in all phases. Innovative powder synthesis and consolidation approaches capable of satisfying all microstructural, porosity, and optical transparency requirements at sample sizes exceeding 2" x 4" x 0.5" are sought. Furthermore, the proposed processes should be industrially scalable in both capacity and final component size, with a path towards producing components in the 3" x 9" range or larger. In addition to these requirements, the composite ceramic must retain its microstructure and IR transparency after exposure to temperatures up to 1200 degrees C for 10 minutes. Phase transformation or grain growth during high-temperature service would degrade both mechanical and optical performance. The composite must also exhibit a low ratio of thermal expansion coefficient (alpha) to thermal conductivity (k). The threshold requirement for alpha/k is 1.0 micrometers/W and the target is 0.5 micrometers/W at 1000C.
PHASE I
Phase I efforts should focus on research to establish the feasibility of a proposed material system and processing approach. Proposals should outline a plan to investigate and demonstrate the potential to produce the target IR-transparent composite ceramic with sub-100 nm microstructural features in all phases and porosity below 0.1%. The research should address initial process tuning, explore pathways to scalability (demonstrating the approach can plausibly be extended to industrially relevant sample sizes), and provide a scientific basis for meeting the optical and thermal property goals. The applicant should also investigate the anticipated thermal stability of the proposed composition to 1200 degrees C and provide an estimate or measurement of the alpha/k ratio. For Direct to Phase II (D2P2) proposals, the applicant is required to provide details and documentation demonstrating accomplishments of a "Phase I-type" effort.
PHASE II
The Phase II effort should mature the proposed technology through focused research and development aimed at scaling the process and optimizing the material. Key research objectives for this phase include, but are not limited to:
Developing and refining a novel composition and process route with the goal of achieving sub-100 nm microstructural features in all phases, porosity below 0.1%, and SWIR/MWIR transparency of at least 80% on samples exceeding 2" x 4" x 0.5".
Investigating and verifying the retention of nanoscale microstructural features (critical to the target mechanical and thermal properties) via SEM/EDS cross-section analysis.
Researching and demonstrating the industrial scalability of the process, including establishing a clear path towards producing components in the 3" x 9" range or larger.
Validating microstructural and optical stability (including maintained SWIR/MWIR transparency and retained sub-100 nm features without deleterious phase transformation) after exposure to 1200 degrees C.
Measuring key thermomechanical properties, specifically targeting an alpha/k ratio at or below the 1.0 micrometers/W threshold (with a target of 0.5 micrometers/W) at 1000 degrees C.
Performing and reporting initial mechanical property characterization, including hardness, flexural strength, and fracture toughness testing at ambient temperature.
Providing representative samples to the Navy for independent characterization, alongside a final cost estimate for continued scale-up and per-unit material cost.
PHASE III DUAL USE APPLICATIONS
The contractor will pursue commercialization of the materials and processes developed during Phase II with ITAR/CUI-eligible organizations. IR-transparent composite ceramics with refined nanostructure have broad potential for dual-use applications including electro-optical/infrared (EO/IR) sensor windows and domes for airborne and maritime platforms, hypersonic vehicle apertures, and commercial thermal imaging systems. The technologies may be transitioned by expanding mission capabilities across a broad range of government users including directed energy, EO/IR sensing, and hypersonic systems programs. Direct procurement of IR-transparent composite ceramic components in coordination with the government program manager may be part of a Phase III program.
REFERENCES
Chaim, R., Levin, M., Shlayer, A., Estournes, C. Sintering and densification of nanocrystalline ceramic oxide powders: a current understanding. Advances in Applied Ceramics, 2008, 107(3), 159-169.
Goldstein, A. Correlation between MgAl2O4-spinel structure, properties and scale-up product performance in IR-windows and domes. Optical Materials, 2012, 35(3), 669-674.
Nordahl, C.S., Hartnett, T., Gattuso, T., Gentilman, R. Optical and Mechanical Properties of Nano-Composite Optical Ceramics. Raytheon Integrated Defense Systems, Portsmouth RI. DTIC Accession No. ADA527006, 2009.
Katsui, H., Goto, T. Coatings on ceramic powders by rotary chemical vapor deposition and sintering of the coated powders. Journal of the Ceramic Society of Japan, 2018, 126, 413-420. DOI: 10.2109/jcersj2.17279
