Additive Manufacturing of High and Ultra-High Temperature Ceramics and Composites: Processing, Characterization and Testing: Polymer-derived Ceramics (PDCs) and Novel Processing Methods
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
Wednesday 10:00 AM
October 20, 2021
Room: A111
Location: Greater Columbus Convention Center
Session Chair: William Costakis, Air Force Research Laboratory
10:00 AM
Advanced Polymer-derived (Ultra)-high-temperature Resistant Ceramics and Ceramic Nanocomposites for Additive Manufacturing: Ralf Riedel1; 1TU Darmstadt
Preceramic polymers were proposed more than 40 years ago as precursors for the fabrication of mainly Si-based advanced ceramics, generally denoted as polymer-derived ceramics (PDCs). The polymer to ceramic transformation process enabled significant technological breakthroughs in ceramic science and technology, such as the development of ceramic fibers, coatings or ceramics stable at ultra-high temperatures (up to 2000°C) with respect to decomposition, crystallization, phase separation and creep. Preceramic polymers have been used as reactive binders to produce technical ceramics, they have been manipulated to allow for the formation of ordered pores in the meso-range, they have been tested for joining advanced ceramic components and have been processed into bulk or macro-porous components. In the present presentation, the focus is another developing field of preceramic polymers, namely their high potential in additive manufacturing technologies which allows for the fabrication of high-temperature resistant advanced ceramics and ceramic (nano)composites with complex geometries and shapes.
10:30 AM
Innovative Route for the 3D Printing of Hybrid Silicon Carbide/Carbon Fiber Nanocomposites: Saja Al-ajrash; 1
A novel route to fabricate SiC/C composite by utilizing preceramic polymers, stabilized polyacrylonitrile fibers, and subsequent 3D printing was introduced in this study. An allyl hydrido polycarbosilane and 1,6-hexanediol diacrylate were mixed with a photoinitiator to form a photosensitive resin. The resulting resin was loaded with distinct weight percentages of oxidized polyacrylonitrile nanofiber. After the pyrolysis, the preceramic polymer formulation converts to mainly SiC matrix while the fibers transform to reinforcing carbon fibers simultaneously within one pyrolysis cycle. The prepared precursor resin proved to have outstanding photo-curing properties and the ability to transform to the silicon carbide phase. The obtained ceramic hybrid composite was mostly dense with nearly linear shrinkage, shiny/smooth surface, and around 60% retained weight after pyrolysis. The composite appeared to have three coexisting phases including SiC, SiOC, and turbostratic carbon. The results are promising to fabricate high-temperature composites with shorter fabrication time and complex geometries.
10:50 AM
High Temperature Properties of Polymer-derived Ceramic Matrix Composites Fabricated via Additive Manufacturing: Tobias Schaedler1; Kayleigh Porter1; Phuong Bui1; Ekaterina Stonkevitch1; Mark O'Masta1; 1HRL Laboratories LLC
Silicon Carbide (SiC) is a sought after high temperature material, but 3D printing of SiC has been challenging. Conventional ceramic printing based on UV curing of acrylate resin slurries with a high volume fraction of particles is hindered by the high index of refraction and low UV transparency of SiC. Difficulties in sintering SiC complicate any 3D printing method that involves debinding and sintering of powders. Here, we demonstrate a novel approach to 3D printing SiC based on preceramic polymers. Carbosilanes are cured thermally or with UV light and subsequently pyrolyzed to an amorphous SiC phase that is crystallized to nano-grained beta SiC. Carbosilane based resins can be tailored for 3D printing and can be easily reinforced with particles or single-crystalline SiC micro-fibers to form ceramic matrix composites. The flexural strength is measured at temperatures up to 1600°C and compared to other 3D printed materials.