Towards Additive Manufacturing of High-Performance Ceramics

Stephen Farias, PhD

Chief Science Officer

Stephen.Farias@matericgroup.com

Flame retardant, conductive, bioprinting

Polymers, non-oxide ceramics, oxide ceramics, tissue culture

Electrospun nanofibers, silver nanowires, synthesis/purification

Drug delivery, encapsulation, insecticide, enzyme

Flame retardant, permethrin encapsulated, IR reflective, nonwovens

Basics of Additive Manufacturing

• Fused Deposition Modeling (FDM)• Heated filament deposited layer

by layer

• Stereolithography (SLA)• Light activated crosslinking

photocuring from solution

• Selective Laser Sintering (SLS)• Laser sintering/fusing of powder

bed

Current AM of Ceramics

• Can do simple clays (pottery and artistic media) using extrusion printers• Fire print in a kiln post print

• Engineering Ceramics• Can be printed via various

techniques using binder formulations

• Need to post-process to remove binders and sinter

Problems for High-Performance Ceramics“The main problem of AM ceramics lies with the formulation of feedstock” [3]

Ultra-High Temperature Ceramics are not directly additively manufactured due to:• Not easily sintered• Laser energy deposition induces microcracking• Incongruent melting (decomposition)

SLS - Powder Bed Fusion

Excessive volume changes/cracking associated with debinding.

[3] A. Zocca, P. Colombo, C. M. Gomes, and G. Jens, “Additive Manufacturing of Ceramics: Issues, Potentialities, and Opportunities,” vol. 98, no. 7, pp. 1983–2001, 2015.[4] M. C. Leu, S. Pattnaik, and G. E. Hilmas, “Investigation of laser sintering for freeform fabrication of zirconium diboride partst” Virtual Phys. Prototyp., vol. 7, no. 1, pp. 25–36, 2012.

Binder Phase Consolidation

Required Post-Processing

25 mm

Laser sintered and post-processed ZrB2 part.[3]

High-Performance Ceramics (Carbides, Nitrides and Borides)

Strongly Covalent Bonds→ High-Melting Temperatures, Structural Stability → Difficult Processing/Part Formation

?

Now: Simple Non-Oxide Coatings

(Above) Ceramic sharp wing

leading edge for hypersonics. [1][2]

Non-oxide (carbides, nitrides, borides) withstand extreme environments and have many adventurous thermal characteristics:

• Extreme temperature (often above Mp >3000°C), oxidation resistance, chemical reactivity, radiation, mechanical stress• Have high thermal conductivity for efficient heat transfer

Note: white bars show spontaneous reaction temperatures for synthesis from metal or metal oxide precursors in CH4 or NH3

Future: Complex, Selectively DepositedUHTC Components

(Above) Ni single-piece

AM rocket engine.

Our Solution: Synteris™ Selective Laser Reaction Sintering (SLRS)

• Laser heating of the precursor causes reaction with the gas to synthesize the desired non-oxide in-situ as parts are being formed

• Reaction occurs spontaneously below melting or sintering temperatures, lowering thermally induced stress

• Particles bind with chemically-induced reaction-bonding

• By altering the reactant gas other non-oxides may be produced (e.g. CH4 for carbides, NH3 for nitrides, etc.)

Conversion of unique Metal/Metal-Oxidecomposite precursor system should satisfy:

1. Full conversion with few impurities

2. Timely conversion

3. Reactive isovolumetric formation

Our Solution: Synteris™ Continued

• By combining specialty precursors for SLRS we can approach net-shape ceramic prints

• Tuned combinations of reactants that expand and contract to form final phase

R1 R2

PC PC

Carbon Source

Carbon Source

Example SiC and TiC Prints

Example 3D TiC Lattice

Acknowledgements

• Johns Hopkins University Inventors• Adam Peters, PhD

• Michael Brupbacher, PhD

• Dajie Zhang, PhD

• Collaborators• Sreekant Narumanchi, PhD - NREL

• Doug Devoto - NREL

• Winston Frazer – Danae Inc

• Funding

• Business Support