DON26BZ01-NV021 — Robocasting Ceramic Sensors

Award Maximum: $140,000 (Base) / $100,000 (Option) Period of Performance: 6 months (Base) + 6 months (Option) Phase Type: Phase I

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

DESCRIPTION: Piezoelectric ceramic materials are essential materials to produce undersea sensors. Many existing undersea sensors rely on a dry press manufacturing process that produces the ceramic components used in many fielded sensors. Existing piezoelectric ceramic components are becoming increasingly difficult to source due to a shrinking supplier base and a desire by many private companies to stop manufacturing lead-based products. Additionally, these components have been largely unchanged since the 1960's with little to no performance enhancements to ships' critical systems.

The goal of this SBIR topic is to support the development of new agile manufacturing techniques to produce large format ceramics and that require less capital overhead and would be easier to stand up in new cottage businesses if the current supply base continues to degrade. The secondary goal is to improve the electrical and acoustic performance of these large format ceramic materials by utilizing textured ceramic technology.

Textured ceramic materials have an aligned microstructure that can exhibit enhanced properties compared to traditionally manufactured ceramics with randomly oriented gains. One documented benefit is an improved piezoelectric performance for sonar sensor applications (early prototypes have shown upwards of 12dB improvement in performance, enabling sensors to detect potential threats much farther out).

The process of robocasting or direct ink writing of a shear thinning ceramic paste shows great potential as a flexible manufacturing technique to produce ceramics for undersea sensors. There has been recent research demonstrating that extruding a ceramic paste through a high aspect ratio nozzle can align high aspect ratio particles within a material, allowing to produce textured piezoelectric ceramics through a robocasting process.

The primary focus of this SBIR topic would be to validate the feasibility to integrate a Navy piezoelectric ceramic with a robocasting or direct ink write slurry system. Key criteria for success will include the ability to consistently extrude a layer of ceramic paste, support proper adhesion between layers, and produce high percent solids loading of the paste; and the ability to sinter the materials to produce dense final parts.

The secondary focus will be to demonstrate the ability of the additive manufacturing hardware to properly align high aspect ratio platelets during the printing process. Common geometries include cylinders with 1in outer diameter as well as rings that are greater than 4in in outer diameter. The awardee will aim to create a prototype that exceeds a capacitance of 200pf while minimizing the loss tangent.

PHASE I: Develop a concept for a ceramic paste suitable for additive manufacturing that utilizes Navy piezoelectric ceramics and can align high aspect ratio ceramic platelets within the constraints listed in the Description. Feasibility may be demonstrated by analysis, modelling, and simulation, the fabrication and testing of initial test geometries, or some combination of all three. 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. 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: Assist the Navy in transitioning the technology to Navy use. Scale/volume/speed of production will also be optimized in this phase. 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. Potential commercial applications include medical imaging devices, civilian watercraft navigation and fishing devices, and infrastructure inspection equipment.

KEYWORDS: Additive manufacturing; Robocasting; Direct Ink Writing; textured ceramics; shear alignment; piezoelectric