Manufacturing and Processing of Advanced Ceramic Materials: New Opportunities in Ceramic Processing II
Sponsored by: ACerS Manufacturing Division
Program Organizers: Bai Cui, University of Nebraska Lincoln; James Hemrick, Oak Ridge National Laboratory; Mike Alexander, Allied Mineral Products; Eric Faierson, Iowa State University; Keith DeCarlo, Blasch Precision Ceramics
Monday 2:00 PM
October 18, 2021
Room: B234
Location: Greater Columbus Convention Center
Session Chair: Ivar Reimanis, Colorado School of Mines; Jian Luo, University of California, San Diego
2:00 PM Invited
Flash Sintering, Ultrafast Sintering without Electric Fields, and Electric Field Effects on Microstructural Evolution: Jian Luo1; 1University of California, San Diego
This talk will review our recent studies on the scientific questions and technological opportunities of flash sintering [Scripta Mater. 146: 260 (2018); MRS Bulletin 46: 26 (2021)]. A thermal runaway model has been developed to forecast the onset flash temperatures [Acta Mater. 94:87 (2015)]. The rapid heating profiles enable the ultrafast densification rates [Acta Mater. 125:465 (2017)]. A generic ultrafast high-temperature sintering was developed in a collaborative study [Science 368:521 (2020)]. A two-step flash sintering (TSFS) technology was invented to densify ceramics with suppressed grain growth [Scripta Mater. 141:6 (2017)]. Using water-assisted flash sintering (WAFS), we can start a flash at room temperature to subsequently densify a ZnO specimen to ~98% densities in 30 s [Scripta Mater. 142:79 (2018)]. Furthermore, flash sintering can also be activated by bulk phase and grain boundary complexion transformations [Acta Mater. 181:544 (2019)]. Electric field effects on microstructural evolution are discussed [see, e.g., arXiv: 2012.15862].
2:40 PM Invited
High Temperature Coatings for Concentrated Solar Power Receivers: Julia Billman1; Ivar Reimanis1; Andrea Ambrosini2; Gregory Jackson1; 1Colorado School of Mines; 2Sandia National Laboratory
Concentrated solar power (CSP) offers a desirable route to convert sunlight to thermal electric power. Current CSP receivers are typically covered with a silicone-based coating that exhibits high solar absorptance but also high emissivity, resulting in radiative heat loss at higher temperatures. It can also degrade under high temperatures > 700 °C. Future CSP systems require novel receiver designs, and thus new receiver coatings are sought. Spinel-based oxide coatings such as CuCr2O4 and MnFe2O4 are particularly promising and have the potential to perform well above 900 °C. The present work describes exploratory efforts to coat stainless steel and nickel-based superalloys via slurry dip-coating followed by sintering. It is demonstrated that the coatings have the ability to survive cyclic rapid heating and cooling. The roles of the coating/receiver interface and the coating microstructure in dictating survivability and performance optimization are discussed in the context of processing.
3:20 PM
Green State Joining of Silicon Carbide for High-temperature Applications: Olivia Brandt1; Rodrigo Orta Guerra1; Rodney Trice1; Jeffrey Youngblood1; 1Purdue University
Silicon carbide (SiC) is useful for high-temperature applications due to its corrosion resistance and strength retention at elevated temperatures. Often the components needed for high-temperature applications are complex and difficult to manufacture. To decrease production costs these complex parts are often created by joining simpler geometries together. One approach to forming SiC powders involves blending it with a thermoplastic polymer followed by extrusion of the mixture above the Tg of the polymer. These extrudates are then joined to create useful shapes. In this study, a blend of SiC/polymers composed of Polyethylene Glycol, Heavy Mineral Oil, Ethylene Ethyl Acrylate, and Poly (Isobutyl Methacrylate) were joined together. A variety of temperatures (100°C-150°C), pressures (0.1-1MPa), and hold times (60-600 mins) were used to determine the viability of SiC green state joining before burnout and sintering. The joints were then characterized by mechanical testing and SEM microscopy to gain insight into the joint strength.
3:40 PM Break
4:00 PM
Self-propagating High Temperature Synthesis of Chevrel Phase Compounds: Milind Pawar1; 1The Ohio State University
Rapidly changing environment and ever-increasing energy demand ask for innovative approach to develop multifunctional materials to tackle these issues. The class of materials known as Chevrel Phase compounds (MxMo6S8-CPs) have re-emerged due to their fascinating properties to serve as a high temperature superconductor, hydrodesulfurization catalyst, thermoelectric material, host for Li/Mg/Al ion in battery applications, as well as electrocatalyst. Traditionally CPs have been synthesized with lab-scale apparatus which requires post processing and longer synthesis time (upto 100 hours). Self-propagating high temperature synthesis (SHS) is a combustion-based process which facilitate synthesis of CPs in single step ultra-fast processing method (2-10 Minutes) which can be scaled up for industrial applications. In this study Cu-CP (Cu2Mo6S8/ Cu4Mo6S8) compounds were synthesized with rapid SHS reaction. Process parameters such as precursor size, mixing and ignition temperature and their effect on final Cu-CP compounds were studied to understand reaction kinetics.