SITIS Topic Details |
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| Proposals Accepted: | |
| Program: | STTR |
| Topic Number: | AF10-BT11 (AirForce) |
| Title: | Photoactivatable Protean Glass/Ceramic Materials | Research & Technical Areas: | Materials/Processes, Sensors |
| Objective: | Development of protean glass/ceramic materials, where RF and DC electrical properties can be imbued in the material volume by laser excitation and subsequent material transformation processes.
| Description: | Glass and ceramics are used in many aerospace applications. They are routinely used as barriers, insulating two very different environments. They also serve as a passive substrate for the incorporation of devices. In limited cases but increasing in use, they serve as “containment” vessels for “extreme” environment reactions (i.e. hypersonic vehicle combustion). Of particular interest to aerospace systems is the desired high strength-to-weight ratio property. Consequently, glass/ceramics have made strong inroads in manufacturing because of the wide variety of mechanical, optical and thermal properties that can be “engineered” by altering the chemical composition and stoichiometry of the constituents. Two specific technology areas keep the glass/ceramics from finding wider use in meso and macro scale applications. 1) In applications where a form must be cut with sub-mm scale features in three dimensions (3D). 2) In applications where the delivery of electrical power is to be an integral part of the glass/ceramic component, nominally because glass/ceramic materials serve as barriers to harsh environments. For the former case the limitation arises because the fabrication of 3D structures with sub-mm scale precision is a costly enterprise. In the latter case, the limitation is the lack of technology for patterning conductors in true 3D and in microscopic dimensions if necessary. While, there is the metal-through-ceramic feed through technology used in electronic packaging, it is not the preferable approach in applications where the electronic lines must be conformal.
A solution to make glass/ceramics more applicable to harsh applications is to explore the inclusion of additives in the glass/ceramic composition that can be initiated by photolytic excitation to induce a transformation which leads with further processing to the desired properties. We can label this kind of material as protean or changeable, mutable. The material is manufactured in a “metastable” state but can be altered to suit. There is a class of photosensitive glass/ceramic materials where the use of optical lithography patterning yields glass/ceramic components with high precision [1-4]. High precision is achieved because the patterning step precedes a chemical processing step and timed etching can be used for control. Modern lithography can be done with pulsed lasers and intimate motion control. Pulsed lasers have high peak powers that can induce exceedingly high temperature jumps (e.g. ~ 1012 K/s) in materials. Pulsed lasers can also initiate material transformations (e.g., phase separation and phase precipitation) via non linear or through non equilibrium processes. There are conflicting reports that with metallic doped glasses, it may be possible to directly precipitate metallic conducting phases within the insulating material by pulsed laser excitation. There are also reports that laser induced transient melting and subsequent re-growth can lead to specific crystalline phases within a material. It is theoretically possible that by controlling the directed energy flux of a pulsed laser with high fidelity, it may be possible to pattern novel phase transformations in protean glass/ceramics by laser direct-write techniques and yield physical property changes to allow the transmission of RF or DC electrical energy in seemingly insulating material.
| PHASE I: Use a combination of experimental, simulation and theoretical research to advance the development of glass/ceramic protean materials whereby a material transformation is initiated by a laser enabling the volumetric patterning of either RF (8-12 GHz) or DC electrical conducting lines within the bulk.
| PHASE II: Based upon the insight developed from the Phase I research results manufacture liter size samples of the material. Fully characterize the protean material properties along with the electrical (RF or DC) and chemical etching properties.
| PHASE III | DUAL USE COMMERCIALIZATION:
Military Application: Sensors, mass producible space platforms, integrated miniature antenna systems, Multifunction space propulsion systems, microwave devices, high temperature components.
Commercial Application: Sensor-rich micro analysis biological systems for point-of-care testing, architectural panels for modern office buildings, optical components, and high temperature ceramics.
| References: | 1. A. Berezhnoi, “Glass-ceramics and Photositalls” English translation of Russian text, (Plenum Press, NY, 1970). 2. S.D. Stookey, “Chemical Machining of Photosensitive Glass,” Ind. Eng. Chem., Vol. 45, (1953) 115. 3. G.H. Beall, “Design and properties of glass-ceramics,” Annu. Rev. Mater. Sci. (1992) pg. 119. 4. P. W. McMillan, “Glass Ceramics”, 2nd Edition, Academic Press (New York), 1979. |
| Keywords: | glass/ceramics, phase separation, laser direct write processing, embedded electrical networks, embedded RF systems, microfabrication, photosensitivity, laser induced phase transformations, material transformation, embedded microwave systems |
Questions and Answers: |
Q: 1. For the electrical circuit problem, is what you're looking for to fabricate something on the complexity level of PC boards or just to make connectors and feedthroughs? |
A: 1. More on than simply connectors or feedthroughs. |
Q: In case DC conductivity is not achievable, can you state what conductivities are of interest at the 8-12 GHz frequencies (or other frequencies) ? |
A: I think any reasonable conductivity would be acceptable, if it is consistent with the requirements of the commercialization plan. |
As of midnight September 1, questions for solicitations SBIR 10.3 and STTR 10.B will no longer be accepted.
To read the solicitation for full proposal preparation and submission details click here. |