N241-040 TITLE: Additive Manufacturing of Textured Piezoelectric Ceramics

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials; Sustainment

OBJECTIVE: Develop a low-cost, flexible manufacturing technique to produce textured piezoelectric ceramics for undersea sensor applications.

DESCRIPTION: Ceramics with a high degree texturing or grain alignment can exhibit enhanced properties compared to traditionally manufactured ceramics with randomly oriented gains. One such property benefitting from gain alignment is improved piezoelectric performance of ceramics used for sonar sensor applications (early prototypes have shown upwards of 12dB improvement in performance, enabling sensors to detect potential threats much farther out). Current manufacturing techniques to produce highly textured ceramics involve using an expensive and complex tape casting technique to properly align the material seed crystals.

Additive manufacturing (AM) could provide a solution by improving the Manufacturing Readiness Level of these new textured ceramic materials and enabling technology insertion at a scalable, cost-effective rate. Current stereolithography (SLA) and digital light processing (DLP) 3D printers create parts by using a light source to polymerize a liquid photopolymer resin to create a high resolution 3D printed part with minimal need for additional post processing. SLA employs a laser to trace the shape of each layer. DLP, on the other hand, projects a mask of a whole cross-sectional layer at a time. Proposals will be evaluated on the modification to the existing photo-polymerized resin systems used in SLA/DLP 3D printers to be compatible with Navy piezoelectric ceramics. Additionally, there is a need to modify existing 3D printing hardware to incorporate the ability to properly align high aspect ratio seed particles within each print layer to produce grain alignment during sintering of the ceramic. Currently, there are very few commercial solutions that have the ability to align particles or fibers within each layer while printing.

The first objective will be to validate the feasibility to integrate a Navy provided piezoelectric ceramic with a photopolymer resin system. The system must demonstrate the ability to properly polymerize with darker colored ceramic materials. Evaluation criteria will include the ability to polymerize each layer, the layer height that is able to be polymerized, adhesion between layers, percent solids loading of the resin as well as density of final parts.

The secondary objective will be to demonstrate the ability of the 3D printing hardware to properly align high aspect ratio barium titanate platelets during the printing process. These platelets should be dispersed in the piezoelectric ceramic resin and aligned within each print layer. Prototype samples of approximately 1in outer diameter cylinders will need to be produced and undergo binder burn off and sintering. Prototype parts that will be electrically and acoustically tested will be sent to a 3rd party that will apply electrodes and pole the piezoelectric ceramic parts. Prototype parts will be evaluated by Naval Surface Warfare Center Crane Division for density, surface finish, particle/grain alignment, texture fraction as well as electrical and acoustic properties. Textured prototype parts will be electrically tested for resonance frequency, capacitance, dielectric constants, and loss factor and then compared to traditionally manufactured non-textured materials. The company will aim to create a material that exceeds a capacitance of 200pf while minimizing the loss tangent. The company will then revisit particle alignment and binder composition as needed in an attempt to improve acoustic and electrical performance.

PHASE I: Develop a concept that will demonstrate the ability to validate the compatibility of 3D printing resin systems with Navy piezoelectric ceramics and for 3D printing hardware that can align high aspect ratio ceramic platelets within the constraints listed in the description. The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop and deliver prototype hardware based on Phase I work and demonstrate the ability to construct a prototype ceramic that meets the constraints listed in the Description. The prototype hardware will be delivered at the end of Phase II ready to be tested by the government.

PHASE III DUAL USE APPLICATIONS: Focus on transferring the technology and knowledge to the Navy. Scale/volume/speed of production will also be optimized in this phase. Finalize the equipment and consumables needed to produce the parts and make the products available for Crane/Navy to utilize/purchase. This new technology will support the Navy programs/platforms by providing advanced piezoelectric transducers with better performance and capability.

This added technology/capability will also assist in other projects that require advanced, textured ceramics including hypersonic radomes as well as various sensors in the commercial sector and the military. This specific technology could be used in commercial and recreation sonar such as fish finders and navigation devices. It could be used to develop high resolution seafloor mapping devices. There are some possibilities of using this technology for communications/data transfer. This technology is also commonly used in the medical field for imaging devices.

REFERENCES:

1. Messing, Gary L. , et al. "Texture-Engineered Ceramics—Property Enhancements through Crystallographic Tailoring." Journal of Materials Research 32, no. 17 (2017): 3219-3241. https://doi.org/10.1557/jmr.2017.207
2. Rueschhoff, Lisa; Costakis, William; Michie, Matthew; Youngblood, Jeffrey and Trice, Rodney. "Additive Manufacturing of Dense Ceramic Parts Via Direct Ink Writing of Aqueous Alumina Suspensions." International Journal of Applied Ceramic Technology 13, no. 5 (2016): 821-830. https://doi.org/10.1111/ijac.12557
3. Walton, Rebecca L.; Kupp, Elizabeth R. and Messing, Gary L. "Additive Manufacturing of Textured Ceramics: A Review." Journal of Materials Research 36 (2021): 3591-3606. https://doi.org/10.1557/s43578-021-00283-6

KEYWORDS: Additive manufacturing; digital light processing; DLP 3D printing; textured ceramics; piezoelectric; undersea sensors; sonar transducer

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