Nanostructured Surfaces for Improved Functional Properties : Poster Session
Sponsored by: TMS Materials Processing and Manufacturing Division, TMS: Surface Engineering Committee
Program Organizers: Rajeev Gupta, The University of Akron; Homnero Casaneda, Texas A&M University; Sandip Harimkar, Oklahoma State University; Arvind Agarwal, Florida International University; Bobby Mathan, James Cook University

Tuesday 6:00 PM
February 28, 2017
Room: Hall B1
Location: San Diego Convention Ctr

J-39: Development of Economic Ta2O5-based Catalytic System towards Efficient Oxygen Evolution Reaction via Surface Engineering: Jun Ding1; 1National University of Singapore
    Designing economical, efficient and durable catalysts towards oxygen evolution reaction (OER) has gained tremendous interest for the wide applications in clean energy technologies, such as solar or electrolytic water splitting and rechargeable metal-air batteries. Conventional OER catalysts, such as Ir, Ru, IrO2 and RuO2, suffer from high cost and limited natural reserves. Recent work on Ni,Fe/Co,Fe-oxyhydroxide reports superior OER catalytic activity, however, Ni and Co are unfavorable because of poisoning and environmental pollution. Herein, we develop a novel, economical and efficient Ta2O5-based OER catalyst. Stable surface structures of Ta2O5 and the corresponding onset overpotentials towards OER are calculated via systematic first-principles simulation. Oxygen site on the stable (200) surface of Ta2O5 is explicitly identified as the most active OER site, possessing a small calculated onset overpotential of 0.25 V. Using the simulated oxygen condition, we successfully grow a (200)-surface-exposed Ta2O5 nanolayer on a carbon cloth by oxygen-controlled pulsed laser deposition.

J-40: Novel Bilayered Nanostructured Ni-Co-SiC/Zn-Ni Composite Coating with Exceptional Tribological and Corrosion Properties by Pulse Electrodeposition: Swastika Banthia1; Saptarshi Das2; Arghya Patra1; Srijan Sengupta1; Siddhartha Das1; Karabi Das1; 1IIT Kharagpur; 2Heritage Institute of Technology, Kolkatta
    We report the development of a novel nanostructured Ni-Co-nano SiC/Zn-Ni bilayered composite coating on mild steel by pulse electrodeposition. Zn-14%Ni (mixture of γ and δ intermetallic) undercoat (10 m thickness) provides anodic protection to mild steel whereas the top Ni-66%Co (22 m thickness) layer provides cathodic protection and exceptional wear resistance due to uniform dispersion of nano SiC (8 wt %) in the matrix. The coating exhibits uniform thickness and excellent adhesion. The bilayered coating has a hardness of 660 VHN and corrosion current density of 0.47A/cm2 with a polarization resistance of 120.37 kΩ/cm2 in 3.5 wt% NaCl. Tribological and corrosion properties of the bilayered coating is better than Ni-66%Co-SiC coating and Zn-14%Ni alloy coating of same thickness.This new approach mitigates the disadvantages of conventionally used coatings by creating a wear resistant top layer and an anodic coating with low corrosion current density as the undercoat for improved corrosion resistance.

J-41: Surfactant Assisted Synthesis of Brown TiO2 and Its Photocatalytic Activity: Swati Naik1; Gabriel Caruntu1; 1Central MichiganUniversity
    Anatase is known to be a photo-catalytically active polymorphic form of TiO2.In this work, we demonstrate one-step low-temperature solution method/vacuum annealing to obtain brown TiO2 followed by its electronic and structural analysis. The experimental evidence clearly implies the stabilization of anatase structure and formation of oxygen vacancies into TiO2 lattice due to the increase in band tailing and thereby shifting of the absorption edge to lower energy. The presence of oxygen vacancies in vacuum annealed samples was determined by EPR and Raman spectroscopy. The photocatalytic activity of white and brown colored anatase TiO2 will be compared to correlate their band gap and in turn, open up a new route to practical applications of TiO2 under visible light.

J-42: Thermal Diffusivity of Cu-based Composite Materials by Volume Fraction Using SPS Process: Sangwoo Kim1; Hyouk-Chon Kwon1; Hyo-soo Lee1; 1Korea Institute of Industrial Technology
    It was investigated that Cu-RGO (Reduced Graphene Oxide) composites were varied by increasing volume fraction of RGO ranged from 0 to 2vol%. The micro-scaled Cu powders and nano-scaled RGO flakes were mixed by ball mill process at 150rpm for 4 hours. The Cu-0~2vol%RGO composite powders were formed. The composite powders were sintered by SPS process at 700℃ for 10mins under 100MPa, and the sintered Cu-RGO composites were characterized by X-ray diffraction, SEM, TEM, raman spectroscopy, and laser flash analyzer. It was observed that the RGO flakes were extensively stuck to the surface of Cu powders in Cu-RGO composite powders, which was considered as an effective path of thermal dissipation in the sintered Cu-RGO composites. It was shown in this study that the thermal diffusivity of Cu-RGO composite were 90~100 m2/s which was similar to that of pure copper.