Exploration of new chemistries and processes for additive manufacturing of ceramics
Abstract
Preceramic polymers are materials that can be converted into ceramics upon heat treatment(e.g., through pyrolysis) with desired composition and mechanical properties. Efforts oninorganic/organometallic (preceramic) polymer chemistry as a new subarea of polymer sciencebegan in the early 1970s. This was prompted by the pressing demands of the defense and aerospaceindustry that required new structural materials that could serve as replacements for metals andmetallic alloys. Such materials were required to (1) be as light or lighter than the metal theyreplace, (2) have high thermal stability, (3) display high strength, fracture toughness and shockresistance, and (4) be resistant to high temperature oxidation and corrosion. Because of theirsuperior high temperature properties, Si-C andSi-N compounds were oy, preceramic polymers are gaining interest as they are particularly attractivefeedstocks for additive manufacturing (AM). ONR desires to enable a single-step, low-temperatureAM process for ceramic manufacturing without the need for post-process pyrolysis. While thisproject is not expected to produce a fully optimized AM process, ONR would like to see theoutcome of the effort to be sufficiently well-developed chemistries and processes which could beemployed in AM engineering in the future. This project will seek to develop new paradigms inpreceramic chemistry and AM processing that will expand the existing chemistries and enablesingle-step printing ofceramic components at low temperatures.Towards that end, we seek to develop a knowledgebase, chemistries and capabilities todesign ul space. Design of new preceramic materials requirescareful consideration of the preceramic material composition. In order to minimize mass lossduring the annealing stage, the precursor material ideally needs to contain a similar relative atomiccomposition to that of the targeted ceramic product (although this does not guarantee the desiredfinal composition due to other factors). Previously explored preceramic polymers have beenenabled by the ability of Si to be catenated through well-defined covalent bonds that ultimatelyend up in the final ceramic. A central challenge emerges when other areas of the periodic table areconsidered, particularly the transition metals, due to the high valency and number of coordinationsites that needs to be occupied to inhibit formation of infusible crosslinks that would prevent facileprocessing or introduce extraneous mass.To tackle this problem, efforts will initially be bifurcated into efforts for (1) developingnew preceramic chemistries and (2) better understanding non-thermal processes (e.g., illumination,activated species, sonic energy) for fusing and ceramizing preceramic materials, with the ultimategoal of combining these two knowledgebases in years 3 and 4 to establish entirely new paradigmsfor ceramic 3D printing. Towards that end, Qi and Losego will exploreand establish single-stepAM approaches that will eliminate a separate pyrolysis step (Track 1), and preceramic materialsplatforms that will utilize and guide the creation of suitable advancements in the AM capabilities(Track 2). In parallel, Ramprasad will establish computational protocols based on densityfunctional theory (DFT) coupled with thermodynamics and excited-state dynamics to determinetransformation pathways to ceramic materials (and feasibility) starting from a variety ofpreceramic materials (Track 3). The outcomes of Tracks 1-3 will guide future investigations byGutekunst from Year 3 onwards (Track 4) of actual synthetic lab chemistry of novel preceramicmaterials and integration with the developed AM platform.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112258
Entities
People
- Ramamurthy Ramprasad
Organizations
- Georgia Tech Research Corporation
- Office of Naval Research
- United States Navy