N24A-T024 TITLE: Additive Manufacturing of Ferroelectric and/or Ferromagnetic Composite

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials; Directed Energy (DE)

OBJECTIVE: Develop a process for additive manufacturing of ferroelectric and/or ferromagnetic composites for High Power Microwave (HPM)applications. The composites should be comprised of at least 50% ferroelectric and/or ferromagnetic material. The final print should be free of large voids (> 1 µm3) and have a shortest dimension of at least one inch. The final sample should be close to final dimensions and have a resolution of < 1mm.

DESCRIPTION: Ferroelectric and ferromagnetic materials are utilized in various ways for HPM development; nonlinear transmission lines (NLTLs), high energy density capacitors, high voltage delay lines, tunable antenna arrays, etc. The development of additive manufacturing and 3D printing has provided inexpensive alternatives to traditional fabrication and prototyping. Currently there are no additive manufacturing processes that provide a prototyping capability for ferroelectric and/or ferromagnetic materials. Currently these ceramic and ferrite materials must be sintered and machined resulting in expensive prototyping and innovation due to material brittleness. Possible solutions include, but are not limited to, Stereolithography (SLA), Fused Deposition Modeling (FDM), and Selective Laser Sintering (SLS).

Production of the materials can be done using any innovative way but must produce a composite with electrical and/or magnetic properties of at least 90% of the ferroelectric and/or ferromagnetic inclusion. Electrical breakdown is a common critical failure mechanism for components in HPM systems that can result when voids are present in the materials. The final prints should be free of all voids greater than 1 µm3.

KEY ADDITIVE MANUFACTURING COMPONENT PARAMETERS

Will be negotiated with each proposal depending on submitted design.

• Smallest print dimension > 1 inch

• Resolution of print < 1 mm

• Material to print ferroelectric and/or ferromagnetic

• Electromagnetic properties = 90% inclusions

• Final dimensions should be = 95% of completed component

o Some post processing is acceptable

PHASE I: Develop design and strategies for an additive manufacturing process of ferroelectric and/or ferromagnetic composites for HPM applications. Perform cost analysis of various options. Determine compatibility with use of ferroelectric and/or ferromagnetic materials. Evaluate sample preparation (whether it is powder, resin, or filament). Evaluate print parameters. Provide a convincing way forward for a Phase II effort.

PHASE II: In consultation and with ONR approval, determine possible limitations of chosen path.

Perform prints to evaluate the following parameters

• Permittivity and/or permeability

• Electrical breakdown strength

• Resolution of print

Perform the preliminary work necessary to prepare for high-power testing and characterization in Phase III.

PHASE III DUAL USE APPLICATIONS: In consultation and with ONR approval, proceed to printing multiple structures to be used as NLTLs, capacitors, inductors, tunable metamaterials, and/or delay lines for evaluation. In consultation and with ONR approval, test and characterize at high power. ONR may also dictate the location and government assets used to verify the test and characterization.

REFERENCES:

1. Benford, James; Swegle, John A. and Schamiloglu, Edl. "High Power Microwaves, Third Edition." CRC Press, 2016.
2. "Advances in High Voltage Engineering." IET. ISBN 0852961588, 2004.
3. "High Voltage Engineering: Fundamentals." Newnes, 2000. ISBN 0-7506-3634-3.
4. Fairbanks, Andrew J.; Darr, Adam M. and Garner, Allen L. "A review of nonlinear transmission line system design." IEEE Access, vol. 8, 2020, pp. 148606-148621.
5. Rangel, Elizete G Lopes; Rossi, José O; Barroso, Joaquim J; Yamasaki, Fernanda S and Schamiloglu, Edl. "Practical constraints on nonlinear transmission lines for RF generation." IEEE Trans. Plasma Sci., vol. 47, no. 1, 2018, pp. 1000-1016.

KEYWORDS: High Power Microwave; HPM weapons; Nonlinear Transmission Lines; NLTLs; Additive Manufacturing; Ferroelectrics; Ferromagnetics

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