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Luo Group's Selected Publications

 “A schematic illustration and a high-resolution transmission electron microscopy image showing that nanometer-thick, sintering-aid-based, quasi-liquid, intergranular and surface films form at a thermodynamic equilibrium below the bulk solidus line in a pair of sintered particles,” from the cover of the August 2012 issue of JAmCerS. Credit: Luo and Fleck; Wiley.

See a feature article in Ceramic Tech Today written by Eileen De Guire and the related review article in the Journal of the American Ceramic Society [95: 2358 (2012)].

Solid-state activated sintering is a well-known phenomenon, but its origin and mechanisms have puzzled the materials science community for more than 50 years. This cover article reviews our recent efforts in resolving this mystery. 

Perhaps more importantly, our long-range scientific goal (with much broader impacts) is to develop grain boundary "phase" (complexion) diagrams (see related research and review articles below, including: PRL 2018, Current Opinion 2016 & 2008, Acta 2017 & 2015, Scripta 2017, JAmCerS 2012, PRB 2011, and APL 2009 & 2008) as new materials science tool and (perhaps) a useful component for the Materials Genome Initiative.  

Invited Review/Overview/Viewpoint Articles (Selected)

Viewpoint Article: "The Scientific Questions and Technological Opportunities of Flash Sintering: From a Case Study of ZnO to Other Ceramics," J. Luo, Scripta Materialia, 146: 260-266 (2018) 

"The Role of Ceramic and Glass Science Research in Meeting Societal Challenges: Report from an NSF‐Sponsored Workshop," K. T. Faber*, T. Asefa, M. Backhaus‐Ricoult, R. Brow, J. Y. Chan, S. Dillon, W. G. Fahrenholtz, M. W. Finnis, J. E. Garay, R. E. García, Y. Gogotsi, S. M. Haile, J. Halloran, J. Hu, L. Huang, S. D. Jacobsen, E. Lara‐Curzio, J. LeBeau, W. E. Lee, C. G. Levi, I. Levin, J. A. Lewis, D. M. Lipkin, K. Lu, J. Luo, J. P. Maria, L. W. Martin, S. Martin, G. Messing, A. Navrotsky, N. P. Padture, C. Randall, G. S. Rohrer, A. Rosenflanz, T. A. Schaedler, D. G. Schlom, A. Sehirlioglu, A. J. Stevenson, T. Tani, V. Tikare, S. Trolier‐McKinstry, H. Wang, and B. Yildiz, Journal of the American Ceramic Society, 100: 1777-1803 (2017) 

"Grain Boundary Complexions in Multicomponent Alloys: Challenges and Opportunities," N. Zhou, T. Hu, and J. Luo, Current Opinion in Solid State and Materials Science, 20: 268-277 (2016)  

"Layering Transitions at Grain Boundaries," J. Rickman and J. Luo, Current Opinion in Solid State and Materials Science, 20: 225-230 (2016) 

"Interfacial Engineering of Solid Electrolytes," J. Luo, Journal of Materiomics (the launching issue), 1: 22-32 (2015) 

"Overview No. 152: Grain Boundary Complexions," P. R. Cantwell, M. Tang, S. J. Dillon, J. Luo, G. S. Rohrer, and M. P. Harmer, Acta Materialia, 62: 1-48 (2014) 

"Developing Interfacial Phase Diagrams for Applications in Activated Sintering and Beyond: Current Status and Future Directions," J. Luo, Journal of the American Ceramic Society, 95: 2358-2371 (2012)    ●  Lead article, with an image featured in the journal cover, in the August 2012 issue  ●  Featured in Ceramic Tech Today and ● American Ceramic Society Bulletin, Vol. 91, No. 8, pages 17-18  ●

"Long Range Interactions in Nanoscale Science," R. H. French, V. A. Parsegian, R. Rodgornik, R. F. Rajiter, A. Jagota, J. Luo, D. Asthagiri, M. K. Chaudhury, Y.-M. Chiang, S. Granick, S. Kalinin, M. Kardar, R. Kjellander, D. C. Langreth, J. Lewis, S. Lustig, D. Wesolowski, J. Wettlaufer, W.-Y. Ching, M. Finnis, F. Houlihan, O. A. von Lilienfeld, C. J. van Oss, and T. Zemb, Reviews of Modern Physics, 82: 1887-944 (2010) 

"Liquid-Like Interfacial Complexion: From Activated Sintering to Grain Boundary Diagrams," J. Luo, Current Opinion in Solid State and Materials Science, 12: 81-88 (2008)  

"Wetting and Prewetting on Ceramic Surfaces," J. Luo and Y.-M. Chiang, Annual Review of Materials Research, 38: 227-249 (2008)   

"Stabilization of Nanoscale Quasi-Liquid Interfacial Films in Inorganic Materials: A Review and Critical Assessment," J. Luo, Critical Reviews in Solid State and Materials Sciences, 32: 67-109 (2007)    ●  Image featured in the journal cover  ●

Representative Research Publications (Selected) 

Grain Boundaries and Their Roles in Materials Fabrication (e.g., Activated Sintering) and Properties (e.g., Embrittlement):

"Role of Disordered Bipolar Complexions on the Sulfur Embrittlement of Nickel General Grain Boundaries," T. Hu, S. Yang, N. Zhou, Y. Zhang, J. Luo*, Nature Communications, 9: 2764 (2018)    ●  Supplementary Information (68 pages)   ●   UCSD News Release  ●

"Segregation-Induced Ordered Superstructures at General Grain Boundaries in a Ni-Bi Alloy," Z. Yu, P. R. Cantwell, Q. Gao, D. Yin, Y. Zhang, N. Zhou, G. S. Rohrer, M. Widom, J. Luo*, and M. P. Harmer*,  Science, 358: 97-101 (2017)    ●   "Giving Grain Boundaries More Structure," Editor's Summary in "This Week in Science"   ●   UCSD News Release  ●

"Identification of a Bilayer Grain Boundary Complexion in Bi-doped Cu," A. Kundu, K. M. Asl, Y. Zhang, J. Luo, and M. P. Harmer, Scripta Materialia, 68: 146-149 (2013) 

"A Grain Boundary Phase Transition in Si-Au," S. Ma, K. M. Asl C. Tansarawiput, P.R. Cantwell, M. Qi, M. P. Harmer, and J. Luo, Scripta Materialia, 66: 203-206 (2012)    

"The Role of a Bilayer Interfacial Phase on Liquid Metal Embrittlement," J. Luo, H. Cheng, K. M. Asl, C.J. Kiely, and M.P. Harmer, Science, 333: 1730-1733 (2011)    ●  Editor's Summary in "This Week in Science"  ●  Clemson News Release  ●

"Decreasing the Grain Boundary Diffusivity in Binary Alloys with Increasing Temperature," X. Shi and J. Luo, Physical Review Letters, 105: 236102 (2010) 

"Grain Boundary Wetting and Prewetting in Ni-Doped Mo," X. Shi and J. Luo, Applied Physics Letters, 94: 251908 (2009) 

"Thin Intergranular Films and Solid-State Activated Sintering in Nickel-Doped Tungsten," V. K. Gupta, D. H. Yoon, H. M. Meyer III, and J. Luo, Acta Materialia, 55: 3131-3142 (2007)  

"Segregation-Induced Grain Boundary Premelting in Nickel-doped Tungsten," J. Luo, V. K. Gupta, D. H. Yoon, and H. M. Meyer III, Applied Physics Letters, 87: 231902 (2005)   

Grain Boundary "Phase" (Complexion) Diagrams:

"First-order Interfacial Transformations with a Critical Point: Breaking the Symmetry at a Symmetric Tilt Grain Boundary," S.Yang, N. Zhou, H. Zheng, S. P. Ong, and J. Luo*, Physical Review Letters, 120, 085702 (2018) 

"Calculation and validation of a grain boundary complexion diagram for Bi-doped Ni," N. Zhou, Z. Yu, Y. Zhang, M.P. Harmer, and J. Luo*, Scripta Materialia, 130: 165-169 (2017) 

"Liquid-Like Grain Boundary Complexion and Sub-Eutectic Activated Sintering in CuO-doped TiO2,"  J. Nie, J. M. Chan, M. Qin, N. Zhou, and J. Luo*, Acta Materialia, 130: 329-338 (2017) 

"Developing Grain Boundary Diagrams for Multicomponent Alloys," N. Zhou and J. Luo, Acta Materialia, 91: 202-16 (2015) 

"Developing Grain Boundary Diagrams as a Materials Science Tool: A Case Study of Nickel-doped Molybdenum," X. Shi and J. Luo, Physical Review B, 84: 014105 (2011)    ●  An Editors' Suggestion ("As a service to both our readers and authors, we list a small number of papers published in Physical Review B that the editors and referees find of particular interest, importance, or clarity. These Editors' Suggestion papers are marked with a special icon that contains the printer's mark that appeared on the covers of all sections of the Physical Review until about a decade ago.")  ●

"Grain Boundary Complexions: The Interplay of Premetting, Prewetting and Multilayer Adsorption," J. Luo, Applied Physics Letters, 95: 071911 (2009)  

"Grain Boundary Disordering in Binary Alloys," J. Luo and X. Shi, Applied Physics Letters, 92: 101901 (2008)  

Flash Sintering:

"Water-Assisted Flash Sintering: Flashing Zno at Room Temperature to Achieve ~ 98% Density in Seconds," J. Nie, Y. Zhang, J. M. Chan, R. Huang, and J. Luo*, Scripta Materialia, 142: 79-82 (2018)    ●  ACerS / Ceramic Tech Today News  ●

"Probing the densification mechanisms during flash sintering of ZnO," Y. Zhang, J. Nie, J.M. Chan, and J. Luo*, Acta Materialia, 125: 465-475 (2017) 

"Two-Step Flash Sintering of ZnO: Fast Densification with Suppressed Grain Growth," J. Nie, Y. Zhang, J. M. Chan, S. Jiang, R. Huang, and J. Luo*, Scripta Materialia, 141: 6-9 (2017) 

"Effects of Phase and Doping on Flash Sintering of TiO2," Y. Zhang, J. Nie, and J. Luo*, Journal of the Ceramic Society of Japan, 124: 296-300 (2016).  (Invited Contribution for a Special Topical Issue on Sintering)

"Promoting the Flash Sintering of ZnO in Reduced Atmospheres to Achieve Nearly Full Densities at Furnace Temperatures of < 120 °C," Y. Zhang and J. Luo, Scripta Materialia, 106: 26-29 (2015) 

"Thermal Runaway, Flash Sintering and Asymmetrical Microstructural Development of ZnO and ZnO-Bi2O3 under Direct Currents," Y. Zhang, J.-I. Jung, and J. Luo, Acta Materialia, 94: 87-100 (2015) 

Cold Sintering:

 "Cold Sintering and Ionic Conductivities of Na3.256Mg0.128Zr1.872Si2PO12 Solid Electrolytes," H. Leng, J. Huang, J. Nie, J. Luo*, Journal of Power Sources, 391: 170-179 (2018) 

High-Entropy Ceramics:

"High-Entropy Fluorite Oxides," J. Gild, M. Samiee, J.L. Braun, T. Harrington, H. Vega, P.E. Hopkins, K. Vecchio, J. Luo*,  Journal of the European Ceramic Society, 38: 3578-3584 (2018) 

"A New Class of High-Entropy Perovskite Oxides," S. Jiang, T. Hu, J. Gild, N. Zhou, J. Nie, M. Qin, T. Harrington, K. Vecchio, and J. Luo*, Scripta Materialia, 142: 116-120 (2018) 

 “High-Entropy Metal Diborides: A New Class of High-Entropy Materials and a New Type of Ultrahigh Temperature Ceramics,” J. Gild, Y. Zhang, T. Harrington, S. Jiang, T. Hu, M. C. Quinn, W. M. Mellor, N. Zhou, K. Vecchio, and J. Luo*, Scientific Reports 6, 37946 

Nanocrystalline Alloys:

"Stabilization of Nanocrystalline Alloys at High Temperatures via Utilizing High-Entropy Grain Boundary Complexions," N. Zhou, T. Hu, J. Huang, and J. Luo*, Scripta Materialia, 124: 160-163 (2016) 

"Developing Thermodynamic Stability Diagrams for Equilibrium-Grain-Size Binary Alloys," N. Zhou and J. Luo, Materials Letters, 115: 268-71 (2014) 

Batteries, Solid Electrolytes, and Supercapacitors:

"Enhancing the Electrochemical Performance of Li-Rich Layered Oxide Li1.13Ni0.3Mn0.57O2 via WO3 Doping and Accompanying Spontaneous Surface Phase Formation," J. Huang, H. Liu, T. Hu, Y. S. Meng, J. Luo, Journal of Power Sources, 375, 21-28 (2018) 

"Enhancing the Ion Transport in LiMn1. 5Ni0. 5O4 by Altering the Particle Wulff Shape via Anisotropic Surface Segregation," J. Huang, H. Liu, N. Zhou, K. An, Y. S. Meng, J. Luo, ACS Applied Materials & Interfaces, 9: 36745-36754 (2017) 

"Divalent-doped Na3Zr2Si2PO12 Natrium Superionic Conductor: Improving the Ionic Conductivity via Simultaneously Optimizing the Phase and Chemistry of the Primary and Secondary Phases," M. Samiee, B. Radhakrishnan, Z. Rice, Z. Deng, Y.S. Meng, S.P. Ong*, and J. Luo*, Journal of Power Sources, 347: 229-237 (2017) 

"Pseudocapacitive Properties of Two-Dimensional Surface Vanadia Phases Formed Spontaneously on Titania,"  M. Samiee, and J. Luo*, ACS Applied Materials & Interfaces, 8: 12871-12880 (2016).

"Composites of Sodium Manganese Oxides with Enhanced Electrochemical Performance for Sodium-Ion Batteries: Tailoring Properties Via Controlling Microstructure," J. Huang, and J. Luo*, a Special Issue of Functional Materials in Science China Technological Sciences, 59: 1042-1047 (2016)

"Interfacial Stability of Li Metal–Solid Electrolyte Elucidated via in Situ Electron Microscopy," C. Ma, Y. Cheng, K. Yin, J. Luo, A. Sharafi, J. Sakamoto, J. Li, K. L. More, N. J. Dudney, and M. Chi*, Nano Letters, 16: 7030–7036 (2016)

"Communication—Enhancing the Electrochemical Performance of Lithium-Excess Layered Oxide Li1.13Ni0.3Mn0.57O2 via a Facile Nanoscale Surface Modification," H. Liu, J. Huang, D. Qian, S. Hy, C. Fang, J. Luo, and Y.S. Meng*, Journal of the Electrochemical Society, 163, A971-A973 (2016)

"Elastic Properties of Alkali Superionic Conductor Electrolytes from First Principles Calculations," Z. Deng, Z. Wang, I.-H. Chu, J. Luo, and S.P. Ong*, Journal of the Electrochemical Society, 163, A67-A74 (2016)

"Suppressed Phase Transition and Giant Ionic Conductivity in La2Mo2O9 Nanowires," W. Liu, W. Pan*, J. Luo*, A. Godfrey, G. Ou, H. Wu, and W. Zhang, Nature Communications, 6, 8354 (2015)

"A Facile and Generic Method to Improve Cathode Materials for Lithium-ion batteries via Utilizing Nanoscale Surface Amorphous Films of Self-Regulating Thickness," J. Huang and J. Luo, Physical Chemistry Chemical Physics, 16: 7786-7798 (2014) 

"A Facile Nitridation Method to Improve the Rate Capability of TiO2 Nanoparticles for Lithium-Ion Batteries," M. Samiee and J. Luo, Journal of Power Sources, 245: 594-598 (2014) 

“Surface Adsorption and Disordering in LiFePO4 Based Battery Cathodes,” A. Kayyar, H. Qian, and J. Luo, Applied Physics Letters, 95: 211905 (2009)  

Surface Adsorption, Disordering and Nanoscale Films in Catalysts and Photocatalysts:

"Enhancing the visible-light photocatalytic activity of TiO2 by heat treatments in reducing environments," M. Samiee and J. Luo, Materials Letters, 98: 205-208 (2013) 

"Nanoscale Surficial Films and A Surface Transition in V2O5-TiO2-Based Ternary Oxide Systems," H. Qian and J. Luo, Acta Materialia, 56: 4702-4714 (2008)  

"Vanadia-Based Equilibrium-Thickness Amorphous Films on Anatase (101) Surfaces," H. Qian and J. Luo, Applied Physics Letters, 91: 061909 (2007)  

Other Fundamental Studies of Surface Adsorption, Disordering and Wetting/Prewetting (Surface Amorphous Films):

"Anisotropic Wetting of ZnO by Bi2O3 with and without Nanometer-Thick Surficial Amorphous Films," H. Qian, J. Luo, and Y.-M. Chiang, Acta Materialia, 56: 862-873 (2008) 

"Nanometer-Thick Surficial Films in Oxides as A Case of Prewetting," J. Luo, Y. -M, Chiang, and R. M. Cannon, Langmuir, 21: 7358-7365 (2005)   

Stabilizing Nanofibers at High Temperatures with Surface Amorphous Films (Collaboration with Tsinghua):

"Stabilizing Nanocrystalline Oxide Nanofibers at Elevated Temperatures by Coating Nanoscale Surface Amorphous Films," L. Yao, W. Pan, J. Luo, X. Zhao, J. Cheng, H. Nishijima, Nano Letters, 18, 130-136 (2018) 

Solution-Based Synthesis of Thin Films and Multilayers:

"Layer-by-Layer Assembly of Sol-Gel Oxide 'Glued' Montmorillonite-Zirconia Multilayers," H. Chen, G.P. Zhang, Z. Wei, K. M. Cooke and J. Luo, Journal of Materials Chemistry, 20: 4925-36 (2010) 

"Solution-Based Synthesis of Oxide Thin Films via a Layer-by-Layer Deposition Method: Feasibility and a Phenomenological Film Growth Model," P. K. Arcot and J. Luo, Surface & Coatings Technology, 202: 2690-97 (2008) 

Liquid Metal Corrosion:

"A Short Review of High-Temperature Wetting and Complexion Transitions with a Critical Assessment of Their Influence on Liquid Metal Embrittlement and Corrosion," J. Luo, Corrosion, 72, 897-910 (2015)  (Invited Contribution for a Special Topical Issue)

"Effects on the Intergranular Liquid Bismuth Penetration in Polycrystalline Nickel," K. M. Asl and J. Luo, Acta Materialia, 60: 149-165 (2012) 

Triple-Line Instability:

 "Observation of an Unusual Case of Triple-line Instability," Y. Zhang and J. Luo, Scripta Materialia, 88: 45-48 (2014) 

Optical Fibers:

"An Overview of Mechanical Strength of Optical Fiber Fusion Splices: Examples of Fractographic Analysis of Break Causes," J. Luo, Fiber and Integrated Optics, 27, 45-60 (2008)   

"Modeling Dissimilar Optical Fiber Splices with Substantial Diffusion," J. Luo, IEEE/OSA Journal of Lightwave Technology, 25: 3575-79 (2007)

Nanoimprinting (Collaboration with Purdue):

 "Large Scale Nanoshaping of Ultrasmooth 3D Crystalline Metallic Structures," H. Gao, Y. Hu, Y. Xuan, J. Li, Y. Yang, R.V. Martinez, C. Li, J. Luo, M. Qi,  G.J. Cheng*, Science, 346: 1352-1356 (2014)    ●  Editor's Summary in "This Week in Science"  ●  Purdue News Release  ●  UCSD News Release  ●


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