Additive Manufacturing of High and Ultra-High Temperature Ceramics and Composites: Processing, Characterization and Testing: On-Demand Oral Presentations
Sponsored by: ACerS Engineering Ceramics Division
Program Organizers: Corson Cramer, Oak Ridge National Laboratory; Greg Hilmas, Missouri University of Science and Technology; Lisa Rueschhoff, Air Force Research Laboratory
Friday 8:00 AM
October 22, 2021
Room: On-Demand Room 1
Location: MS&T On Demand
Additive Manufacturing of Silicon Nitride Using a Slurry Approach: Beth Armstrong1; Corson Cramer1; Benjamin Lamm1; Trevor Aguirre1; David Mitchell1; 1Oak Ridge National Laboratory
Additive Manufacturing of Silicon Nitride Using a Slurry Approach Beth L. Armstrong1*, Corson L. Cramer2, Benjamin Lamm1, Trevor Aguirre2, and David J. Mitchell1 1. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 2. Manufacturing Science Division, Oak Ridge National Laboratory, Oak Ridge, TN Additive Manufacturing (AM) of silicon nitride using nonaqueous or aqueous slurry approaches continues to draw interest for the fabrication of complex shaped ceramic components for high temperature applications. The variables that impact the processability of slurry-based AM are similar to those of traditional ceramic processing techniques. Powder characteristics, such as particle size, surface area, and morphology, and their effect on the powder-solvent interface will be explored as it relates to zeta potential, rheological behavior, and ultimately, “printability” and sintered density. Examples utilizing lithography and extrusion-type slurry printing will be presented. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy.
Investigation of Oxidation Behavior of ZrB2-SiC Composites under Different Partial Pressures of Oxygen: Rubia Hassan1; Rishabh Kundu2; Kantesh Blaani1; 1Indian Institute of Technology Kanpur; 2National Institute of Technology Rourkela
ZrB2 composites with two different SiC particle sizes (D50 ~ 30 µm and ~5 µm) were processed using spark plasma sintering. Densification of ~ 89 and ~ 98 % was obtained for coarse (ZSC) and fine (ZSF) SiC reinforced composites, respectively. The oxidation behavior of the composites tested at 1500 °C for 3 hours under two pO2 viz. 0.21 atm and 2*10-5 atm showed easier oxygen influx through ZSC forming thicker silica layer (~ 9-94 µm) which could protect the bulk for longer duration at 0.21 atm. In the case of ZSF, thinner silica layer (~ 4 µm) was formed. Thickness of layers in both the composites increased with decreasing pO2, signifying rapid oxidation taking place at lower pO2. ZSF at 2*10-5 atm possessed finer ZrO2 particles on the surface resulting in higher oxidation resistance. Thus, a trade off in the SiC particle size is required based on practical application.
AM of UHTCs at LLNL: James Cahill1; 1Lawrence Livermore National Laboratory
We explore the production of complex-shape ultrahigh-temperature ceramic parts using a variety of additive and advanced manufacturing techniques. Factors such as powder particle morphology, presence of binders, green body density, feature sizes, and pressureless sintering conditions are examined and considered. New powder feedstock engineering techniques are implemented for rheology control. High-temperature testing techniques are used to evaluate the survivability of UHTC coupons.
Additive Manufacturing of Corrosion Resistant UHTC Materials for Chloride Salt-to-sCO2 Brayton Cycle Heat Exchangers: James Kelly1; Jeffery Haslam1; Lauren Finkenauer1; Michael Ross1; Pratanu Roy1; Du Nguyen1; Joshuah Stolaroff1; 1Lawrence Livermore National Laboratory
Triply periodic minimal surface (TPMS) geometries can only be fabricated by additive manufacturing methods and are of interest for their potential in heat exchangers. These TPMS topologies can provide up to 10x higher heat transfer coefficients per unit reactor volume, have smooth features that generate only a moderate pressure drop, and have superior structural stability under various loading conditions. Ceramic TPMS heat exchangers have the potential to operate at very high temperatures and pressures with increased operating efficiencies. The properties of ultra-high temperature ceramic (UHTC) materials are also favorable for heat exchangers and potentially suited to future concentrated solar power (CSP) systems based on molten salt media used to heat sCO2 in a closed-loop Brayton power cycle. Prior to establishing the most suitable UHTC materials for CSP applications, initial effort has been focused on printing TPMS substructures with binder-jet additive manufacturing and developing sintering parameters for a strategically selected UHTC.
Additive Manufacturing of High-performance Advanced Ceramics by the Ceramic On-demand Extrusion (CODE) Process: Ming Leu1; 1Missouri University of Science and Technology
Fabrication of dense ceramic parts with complex geometries by extrusion-based additive manufacturing processes is challenging due to the paste’s non-Newtonian behavior, compressibility, and inhomogeneity and the required precise control of the extrusion start and stop to dispense the paste on demand. We have developed an extrusion-based additive manufacturing process, called Ceramic On-Demand Extrusion (CODE), for fabricating highly dense ceramic components from aqueous, high-solids-loading pastes. Afterwards, the fabricated parts are dried in a humidity-controlled chamber and then sintered under atmospheric conditions. The mechanical properties of sintered samples were compared to those from conventional manufacturing processes and other ceramic additive manufacturing processes. Also investigated were sacrificial materials used to build support structures for fabricating complex ceramic components with overhangs, cooling channels, etc. For fabricating parts with functionally graded materials, a dynamic mixer and an extrusion control scheme were developed for fabricating parts with material compositions graded in real time.
Molten Chloride Salt Corrosion Testing of Ultra High Temperature Ceramics for High Temperature Heat Exchangers Fabricated by Additive Manufacturing Methods
: Jeffery Haslam1; James Kelly1; Joshuah Stolaroff1; Michael Ross1; Stephen Raiman2; Bruce Pint3; Dino Sulemanovic3; 1LLNL; 2Texas A&M University; 3ORNL
Additive manufacturing methods allow printing of ceramic powder structures in complex configurations, which can then be sintered to high relative density. One application is to print and sinter Ultra High Temperature Ceramic (UHTC) heat exchangers for use in extracting thermal energy stored in molten salts for power generation applications. In particular, additive manufacturing methods can allow fabrication of Triply Periodic Minimal Surface structures that can increase the volumetric efficiency of heat exchangers. For material screening purposes, a set of corrosion exposure tests were performed with commercial samples of UHTC materials in closed crucible tests at 800°C for 100 hours in a KCl/MgCl2 salt. Dry salt and some wet salt tests were performed. Several UHTC materials including tungsten carbide showed promise in comparison to HaynesTM 230 nickel alloy samples that were tested to provide a relative comparison under the same conditions.
Pathways to Additively Manufacture Ultra-high Temperature Ceramic Composites: James Kemp1; Zlatomir Apostolov2; Brett Compton1; Lisa Rueschhoff3; 1The University of Tennessee, Knoxville; 2Air Force Research Laboratory ; 3Air Force Research Laboratory
Ultra-high temperature ceramics (UHTC) and their composites (UHTCMCs) are of interest for use in harsh environments encountered by next-generation aerospace vehicles but are limited by their ability to be processed into complex-shaped components. A solution is through additive manufacturing (AM) via direct ink writing (DIW), which allows for the complex shaping of ceramics and composites with high feature resolution. To create complex ceramic shapes, shear-thinning, visco-elastic tailored inks are developed with both preceramic polymers and aqueous slurries and are extruded layer-by-layer. Each set of preceramic- or aqueous-based inks contained zirconium diboride (ZrB2), an UHTC, and various loadings of silicon carbide (SiC) chopped fibers. This study includes an analysis of the rheology and printability of inks and the effects of printing parameters on final ceramic development. Additionally, a description of ceramic conversion processing parameters is given, focusing on porosity comparison between preceramic and aqueous-based inks.
Deposition of UHTC Coatings on Refractory Substrates by Directed Energy Methods: Zlatomir Apostolov1; Noam Eliaz2; Michael Cinibulk1; 1Air Force Research Laboratory; 2Tel Aviv University
Extreme environments and advanced design architectures impose increasingly demanding requirements on the survivability and manufacturability of high-speed aerial platforms. Leading edges and control surfaces carry the brunt of environmental loads and require levels of protection surpassing those of the rest of the aeroshell. Ultra-high temperature ceramics (UHTCs) are often the material of choice to serve as protective coatings; however, their durability, paired with complex surface geometry and state of the respective substrates, can create significant obstacles towards efficient coating deposition. Here we introduce a recent effort exploring the deposition of UHTC compositions as coatings on C- and SiC-based composite substrates by Directed Energy methods. Characterization of the substrates and powder feedstock, as well as preliminary melt studies of candidate compositions and blends are presented. Additionally, routes to address some of the foreseeable obstacles, as encountered in previous work by the authors and others in the field, will also be discussed.
Strategies for Printing Continuous Fibers and Post-processing for Ceramic Matrix Composites (CMCs): Corson Cramer1; Vipin Kumar1; Ryan Duncan1; David Mitchell1; Vlastimil Kunc1; 1Oak Ridge National Laboratory
Recent advances in AM of continuous fibers, combined with traditional infiltration processes, have enabled the fabrication of ceramic matrix composite (CMC) components with complex shapes. In this work, we report results of the manufacturing processes, characterization and evaluation of silicon carbide composites fabricated by compression molding, additive manufacturing, and automatic fiber placement of carbon and silicon carbide fibers. Continuous fibers are formed with printing matrices such as thermoplastics and thermosets such as phenolic resins and preceramic polymers. Pyrolysis of the printing matrix materials is done to form carbon coatings around printed fibers, and the fiber preforms are densified with strategies such as polymer impregnation and pyrolysis (PIP), reactive silicon melt infiltration (RMI), and chemical vapor infiltration (CVI). The ability to make continuous fiber preforms and densify to make advanced CMCs is demonstrated, and the role of continuous fibers and microstructure on mechanical properties is discussed.