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1. α-Alumina and spinel react into single-phase high-alumina spinel in <3 seconds during flash sintering

   https://doi.org/10.1111/jace.15927  

   Kok, David; Yadav, Devinder; Sortino, Emanuele; McCormack, Scott J.; Tseng, Kuo-Pin; Kriven, Waltraud M.; Raj, Rishi; Mecartney, Martha L. (February 2019, Journal of the American Ceramic Society)

   In situ X-ray diffraction measurements at the Advanced Photon Source show that alpha-Al2O3 and MgAl2O4 react nearly instantaneously and completely, and nearly completely to form single-phase high-alumina spinel during voltage-to-current type of flash sintering experiments. The initial sample was constituted from powders of alpha-Al2O3, MgAl2O4 spinel, and cubic 8 mol% Y2O3-stabilized ZrO2 (8YSZ) mixed in equal volume fractions, the spinel to alumina molar ratio being 1:1.5. Specimen temperature was measured by thermal expansion of the platinum standard. These measurements correlated well with a black-body radiation model, using appropriate values for the emissivity of the constituents. Temperatures of 1600-1736 degrees C were reached during the flash, which promoted the formation of alumina-rich spinel. In a second set of experiments, the flash was induced in a current-rate method where the current flowing through the specimen is controlled and increased at a constant rate. In these experiments, we observed the formation of two different compositions of spinel, MgO center dot 3Al(2)O(3) and MgO center dot 1.5Al(2)O(3), which evolved into a single composition of MgO center dot 2.5Al(2)O(3) as the current continued to increase. In summary, flash sintering is an expedient way to create single-phase, alumina-rich spinel. 

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2. Ultralow wear Perfluoroalkoxy (PFA) and alumina composites

   https://doi.org/10.1016/j.wear.2016.06.003  

   Sidebottom, Mark A.; Pitenis, Angela A.; Junk, Christopher P.; Kasprzak, Daniel J.; Blackman, Gregory S.; Burch, Heidi E.; Harris, Kathryn L.; Sawyer, W. Gregory; Krick, Brandon A. (September 2016, Wear)
3. Cerium-free Luche reduction directed by rehydrated alumina

   https://doi.org/10.1016/j.tet.2016.03.017  

   Jones-Mensah, Ebenezer; Nickerson, Leslie A.; Deobald, Jackson L.; Knox, Hailey J.; Ertel, Alyssa B.; Magolan, Jakob (June 2016, Tetrahedron)
4. Alumina Graphene Catalytic Condenser for Programmable Solid Acids

   https://doi.org/10.1021/jacsau.2c00114  

   Onn, Tzia Ming; Gathmann, Sallye R.; Wang, Yuxin; Patel, Roshan; Guo, Silu; Chen, Han; Soeherman, Jimmy K.; Christopher, Phillip; Rojas, Geoffrey; Mkhoyan, K. Andre; et al (May 2022, JACS Au)
5. Zirconia-Toughened Alumina Coated Ti6Al4V via Additive Manufacturing

   https://doi.org/doi.org/10.1016/j.matlet.2021.129577  

   Avila, Jose; Bandyopadhyay, Amit (May 2021, Materials letters)

   null (Ed.)

   Processing and characterization for zirconia toughened alumina (ZTA) coatings on Ti6Al4V (Ti64) alloy by directed energy deposition (DED)-based additive manufacturing (AM) is presented here. The objective of the study was to achieve a dense ZTA coating with the intent of providing an alternative to fully ceramic implants for articulating surfaces of total hip arthroplasty (THA). Preliminary work resulted in failed samples due to cracking, porosity, and delamination. After careful parameter optimization, a Ti64+5wt.%ZTA (5ZTA) composition produced a metallurgically sound and coherent coating with minimal porosity. Additionally, bulk structures were also feasible with the optimized coating parameters. Characterization of the 5ZTA composition displayed a 27.0% increase in hardness, 25% reduction in normalized wear rate, an increase in contact resistance during in vitro tribological testing along with a faster surface re-passivation post-tribological testing. 

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