Structure/Properties of Surfaces and Interfaces:

My research group investigates wear-resistant and diffusion-barrier interfaces/coatings with applications targeted for orthopedic/dental implant materials. A primary focus is to develop well-adhered nanostructured diamond coatings onto cobalt-chromium and cemented tungsten carbide metals. Chemical Vapor Deposition (CVD) of diamond and other hard forms of carbon continues to be a very active area of research, particularly in the field of tribology where coatings of high hardness and low friction are required. Much interest has been generated in the synthesis of hard carbon films exhibiting a wide range of structural forms and properties. The computer hard-disc, cutting tool, and biomedical implant industries are only a few examples in which hard carbon coatings have been investigated. We are interested in tailoring the chemistry and structure at interfaces between diamond and metal so that coating adhesion is improved to the level needed for these applications. This includes studying interfacial nitrides, oxides, carbides, and more recently borides that can provide effective diffusion barriers and improve interfacial bonding.

High-Entropy Ceramics:

High entropy alloys and ceramics typically consist of four or more principal components that form a solid solution structure, instead of complex phases (e.g., intermetallics), and are stabilized by their high configurational entropy of mixing. In 2016, the fabrication of single-phase high-entropy boride (HEB) was first reported, representing the first non-oxide high-entropy ceramic fabricated in bulk form. My group is investigating a novel approach for synthesis of high-entropy transition metal borides enabled by microwave-induced plasma. With expected advantages over conventional processes including enhanced diffusion, reduced energy consumption, very rapid heating rates and considerably reduced processing times, decreased sintering temperatures, and improved physical and mechanical properties, the fundamental knowledge gained from this approach will accelerate progress in the field of high entropy ceramic materials. Our current focus is on the role of the microwave plasma process on reaction pathway and kinetics of HEB formation.

• PH 221: General Physics I
• PH 223: General Physics III: Thermodynamics & Quantum Physics
• PH 350: Computation, Theory, and Measurement in Quantum Physics and Relativity
• PH 450: Introductory Quantum Mechanics
• PH 487: Nanoscale Science and Applications

• B. Storr, D. Kodali, K. Chakrabarty, P. A. Baker, V. Rangari, and S. A. Catledge, Single-Step Synthesis Process for High-Entropy Transition Metal Boride Powders Using Microwave Plasma. Ceramics 4, 257 (2021). doi.org/10.3390/ceramics4020020
• Seth Iwan, Kaleb C. Burrage, Bria C. Storr, Shane A. Catledge, Yogesh K. Vohra, Rostislav Hrubiak, and Nenad Velisavljevic. High-pressure high-temperature synthesis and thermal equation of state of high-entropy transition metal boride. AIP Advances 11, 035107 (2021).
• Bhavesh Ramkorun, Kallol Chakrabarty and Shane A Catledge, Effects of direct current bias on nucleation density of superhard boron-rich boron carbide films made by microwave plasma chemical vapor deposition, Materials Research Express 8 046401(2021); doi.org/10.1088/2053-1591/abf38c
• Gopi Samudrala, Kallol Chakrabarty, Paul Baker, Bernabe Tucker, Yogesh Vohra, and Shane Catledge. Selective Deposition of Hard Boron-Carbon Microstructures on Silicon. Materials 14(6) 1397 (2021).
• K. Chakrabarty, W.-C. Chen, P.A. Baker, V.M. Vijayan, C.-C. Chen, S.A. Catledge. Superhard Boron-Rich Boron Carbide with Controlled Degree of Crystallinity. Materials 13, 3622 (2020). www.mdpi.com/1996-1944/13/16/3622
• Rau, K. Chakrabarty, W. Gullion, P.A. Baker, I. Bikmukhametov , R.L. Martens, G.B. Thompson and S.A. Catledge. A diffusion approach for plasma synthesis of superhard tantalum borides. Journal of Materials Research, 35(5), 481-490 (2020). doi.org/10.1557/jmr.2019.357
• Baker, P.A., Chen, W., Chen, C., Shane A. Catledge, and Y. K. Vohra. First-Principles Predictions and Synthesis of B50C2 by Chemical Vapor Deposition, Sci Rep 10, 4454 (2020). a href="https://doi.org/10.1038/s41598-020-61462-9">doi.org/10.1038/s41598-020-61462-9
• Vijayan VM, Tucker BS, Hwang PTJ, Bobba PS, Jun HW, Catledge SA, Vohra YK, Thomas V. Non-equilibrium organosilane plasma polymerization for modulating the surface of PTFE towards potential blood contact applications. J Mater Chem B. 8(14), 2814-2825 (2020). doi: 10.1039/c9tb02757b.

• Nominated, UAB President’s Award for Teaching Excellence, 2015