Nanostructured Surfaces for Improved Functional Properties : Session I
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

Wednesday 8:30 AM
March 1, 2017
Room: Pacific 23
Location: Marriott Marquis Hotel

Session Chair: Rajeev Gupta, The University of Akron; Sandip Harimkar, Oklahoma State University

8:30 AM  Invited
Surface Alloying, Grain Refinement and Corrosion Response in Grain Size Gradient Microstructures: Heather Murdoch1; Joseph Labukas1; Jim Catalano1; Kristopher Darling1; 1Army Research Laboratory
    Grain size gradients concentrate the desired properties from nanocrystallinity (e.g. hardness, wear, corrosion resistance) at the treated surface while maintaining bulk part ductility; in some recent cases even conveying a synergistic overall strengthening. The relationship between grain size and corrosion response is complicated by the effects of processing routes to achieve grain refinement, especially in severe plastic deformation treatments which are likely to involve higher levels of contamination from impact or tool media. We explore some of the effects of surface deformation processing and the resultant grain size gradient on corrosion behavior and mechanical properties. Additionally, in our Surface Mechanical Attrition Treatment (SMAT) process we have also purposefully introduced metal powders to the surface, taking advantage of the inherent mechanical mixing to create a surface alloy layer in addition to grain refinement. This offers the opportunity to tailor both the microstructure and the surface chemistry for corrosion response.

8:50 AM  
Advanced Laser Surface Processing of Thermally-Stable Nanocrystalline Alloys: Kendrick Mensink1; Guillermo Aguilar1; Suveen Mathaudhu1; 1University of California Riverside
    Nanocrystalline (NC) and ultrafine-grained (UFG) materials have been shown to improve properties such as strength and wear resistance over their coarse-grained counterparts. One factor limiting broader NC material usage is that grain growth occurs at temperatures as low as room temperature, which negates the improved NC properties. Recently reports on novel binary alloy systems have demonstrated remarkable thermal stability via minimization of the grain boundary interfacial energy through predicted solute additions. In this study, we present a laser alloying and shock processing as a new strategy for enabling thermally-stable nanostructured surface layers. Microstructures, thermal stability, hardness and tribological results are reported along with comparisons with traditional approaches for thermally-stable NC material synthesis. The findings forecast the ability for generating ultra-strong and wear-resistant surfaces in a variety of structural materials.

9:10 AM  Invited
Temporary Implants for Bone Fracture Healing: Nanosurface Engineering: Bobby Kannan Mathan1; 1James Cook University
     Serious bone fractures often require surgical repair using implants. Current practice limits these implants primarily to non-degradable metallic materials such as stainless steel, titanium alloys and chromium-cobalt alloys. However, the long-term exposure of these implants greatly increases the risk of complications such as foreign body reactions and inflammation due to the release of ions or particles. This leads to the necessity of a secondary surgery to remove the implant after sufficient tissue healing. Metallic magnesium is an attractive implant material for fracture bone healing. Magnesium is biocompatible and degrades naturally in the physiological environment. However, the major issue is that pure magnesium degrades rapidly in body fluid. As a result, magnesium implants dissolve well before the expected service life.In this talk, nanosurface engineering of magnesium-based materials for enhanced degradation resistance will be presented.

9:30 AM  
Corrosion Resistance and Chemical Stability of Super-hydrophobic Electrodeposited Nickel-cobalt Film: Shohreh Khorsand1; Keyvan Raeissi2; Fakhreddin Ashrafizadeh2; Maria Arenas3; 1Brunel University London; 2Isfahan University of Technology; 3National Center for Metallurgical Research
    A simple electrodeposition process was proposed to fabricate super-hydrophobic nickel-cobalt alloy coating without modification by low free energy materials. The contact angle and water repellence properties of the Ni-Co film were measured to determine its wettability. The Ni-Co film exhibited excellent super-hydrophobic properties with a static water contact angle of 158 and a sliding angle of ≤5. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentiodynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt. %). Moreover, to study the long-term stability of the super-hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super-hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate.

9:50 AM Break

10:05 AM  Invited
Nanostructured Coatings for Wear and Corrosion Resistance: Gary Doll1; 1The University of Akron
    The ability to tailor coatings on the micro- and nanoscale has enabled the development of coatings that provide high levels of wear and corrosion resistance to metallic substrates. Although nanostructured coatings can be deposited by various means, this presentation will focus on coatings deposited by three different processes: closed-field unbalanced magnetron sputtering, pulsed reverse current electrodeposition, and thermal reactive deposition. Closed-field unbalanced magnetron sputtering is commonly used to deposit metal-containing diamond like carbon coatings. The deposition process parameters of this technique can be tuned to generate nanocomposite coatings consisting of amorphous hydrocarbon matrices containing nanocrystalline metal carbide precipitates. NiW coatings with and without nanocrystalline ceramics deposited by pulsed reverse current electrodeposition can possess grain sizes less than 5 nm. Finally, nanocrystalline metal carbide coatings can be created on carbon steel substrates through thermal reactive diffusion processes.

10:25 AM  
The Effects of Mn Addition on the Tribocorrosion Behavior of Al–Mn Coatings: Hesham Mraied1; Wenjun Cai1; 1University of South Florida
    The increasing demand for materials suitable for complex service conditions requires the design of new engineering materials resistant to both wear damage and corrosion degradation. Tribocorrosion, material degradation caused by the combined effects of wear, corrosion, and their synergy, is most prominent for passive metals such as aluminum and its alloys, which spontaneously form a passive film when in contact with oxygen or water. When mechanical wear takes place during corrosion, the passive film can be locally destroyed, with the ensuing depassivation leading to rapid localized corrosion and early component failure. In this work, the effects of Mn alloying on the tribocorrosion behavior of Al-Mn coatings were systematically investigated in 0.6 M NaCl aqueous solution. Mn was found to be highly effective in improving the wear, corrosion, and tribocorrosion resistance of Al. Higher Mn concentration improves the protectiveness of passive film, hardness, and repassivation kinetics of the coating.

10:45 AM  
Plasma Spray Deposition of Aluminum-Boron Nitride Nanotube Composite: Pranjal Nautiyal1; Cheng Zhang1; Arvind Agarwal1; 1Plasma Forming Laboratory, Florida International University
    Aluminum-Boron Nitride Nanotube (Al-BNNT) composite is deposited by plasma spray technique for the first time. Fracture surface investigation confirms the survival of the long nanotubes during plasma spray and elucidates their integration in the deposited metal matrix. Microstructure of this novel composite coating is examined to develop insight into metal-nanotube interactions during rapid melting-solidification in plasma spray process. Mechanical properties are evaluated by microhardness and nanoindentation techniques to unravel the bulk as well as localized deformation behavior of the composite coating. The mechanical testing results are correlated with electron microscopy investigations to develop an understanding of the associated strengthening mechanisms. This work is of potential interest for developing light weight, high strength composite coatings for aerospace and automotive applications.

11:05 AM  
Corrosion Behavior of Boron Nitride Nanosheet Reinforced Copper Matrix Composite Coatings: Shei Sia Su1; Cengiz Yegin1; Winson Kuo1; Mustafa Akbulut1; Homero Castaneda1; 1Texas A&M University
    Nanocomposite coating have attracted extensive interest due to their improved mechanical, physical and chemical properties. In this work, novel copper-boron nitride (Cu-BN) nanocomposite coating was fabricated through co-electrodeposition. The effect of boron nitride reinforcement within the metal matrix on the corrosion behavior was studied in details and compared with pure copper coating. The copper nanocomposite coating were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX). Corrosion protection behavior of Cu-BN nanocomposite coating in 3.5% NaCl were evaluated by potentiodynamic polarisation studies (Tafel) and electrochemical impedance spectroscopy studies (EIS).