Recent Developments in Biological, Structural and Functional Thin Films and Coatings: Poster Session
Sponsored by: TMS Functional Materials Division, TMS: Thin Films and Interfaces Committee
Program Organizers: Adele Carradò, Université de Strasbourg IPCMS; Nancy Michael, University of Texas at Arlington; Ramana Chintalapalle, UTEP; Heinz Palkowski, Clausthal Univ of Technology; Vikas Tomar, Purdue Univ; Nuggehalli Ravindra, NJIT

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

Session Chair: Ramana Chintalapalle, University of Texas at El Paso, UTEP; Nuggehalli Ravindra, New Jersey Institute of Technology

H-35: Effects of Carbon Coating on Magnetic Susceptibility of NiTi Alloy: Ari Shin1; Sang Jin Park1; Jun Hyun Han1; 1Chungnam National University
    Magnetic Resonance Imaging (MRI) is a medical imaging technique used in the diagnosis and follow-up of diseases. However, magnetic susceptibility mismatch between human tissue and foreign metallic objects such as stents or implants can induce the distortions in MR images. In order to solve the problem, new algorithms to adjust the artifacts have been developed. While, it is very difficult to develop novel biomaterials having not only biocompatibility and excellent mechanical properties but also low MR image distortion. We propose a way to reduce the MR image distortion while maintaining the inherent biocompatibility and mechanical properties. The magnetic susceptibility mismatch between human tissue and biomaterials such as NiTi alloys that have paramagnetic property can be offset by coating carbon-based materials with strong diamagnetic property. After coating the carbon-based materials on the surface of the NiTi alloys, their magnetic susceptibilities were analyzed and MR image distortion was evaluated.

H-36: Investigation of Mechanical Properties of W1-yMoyO Nanocomposite Thin Films: P. Dubey1; G. Lopez1; G. Martinez1; C. Ramana1; 1University of Texas at El-Paso
    The present work reports the mechanical properties of ~60 nm thick W1-yMoyO nanocomposite films. The W1-yMoyO thin films of various Mo contents (y = 0.7, 1.6 and 5.4 atomic %) were sputtered onto Si(100) at various growth temperatures ranging from 25 șC to 500 șC. The effect of Mo contents and temperatures on the growth behavior, crystal structure, surface morphology, chemical composition and mechanical properties of W1-yMoyO nanocomposite thin films have been studied in detail. The results indicate that the effect of temperatures is significant on the growth and microstructure of W1-yMoyO films. XRD results indicate that crystallization of W1-yMoyO occur at 300 șC. W1-yMoyO phase starts to grow in WO<3> and MoO<3> monoclinic phases. The peak intensities of MoO<3> monoclinic phase increases with increasing Mo content in the films. The effect of evolved microstructure is remarkable on the mechanical properties of W1-yMoyO films grown at various temperatures.

H-37: Microstructure and Optical Properties of HfO2/Mo/HfO2 Based Heat Mirrors and Their Potential Use for Efficient Windows Applications: Juan Gomez1; Paritosh Dubey1; C. Ramana1; 1University of Texas at El Paso
    The presented work is based on the microstructure and optical characterization of heat mirrors based on dielectric/metal/dielectric materials. The effect of variable Mo (metal) thickness on the optical properties and microstructure of HfO2/Mo/HfO2 based heat mirror is evaluated. Unheated glass substrates were employed with multy-HfO2 (dielectric) layers with a fixed thickness of 40 nm while varying the Mo metal interlayer thickness in the range of 25-5 nm. The optical properties of the films reveal a higher transmittance (%) of the films in the infrared (IR) to the near infrared (NIR) region, whereas it reduces in the visible region suggesting a more feasible application for these devices for heat collection. A detailed analysis of the optical constants i.e. refractive index, band gap energy, and absorption coefficient, are evaluated for HfO2/Mo/HfO2 multilayered devices. Comparison of the data will be presented and discussed to determine the optimum Mo interlayer thickness.

H-38: Preparation of Porous Titanium Oxide Film by Sol-gel Method: Baoqiang Xu1; 1National Engineering Laboratory for Vacuum Metallurgy, Key Laboratory of Nonferrous Metals Vacuum Metallurgy of Yunnan Province, Kunming University of Science and Technology
    In this paper, porous titanium dioxide films were prepared through sol-gel route by using tetrabutyl titanate,Ti(OC4H9)4 as a precursor and PEG as pore-forming agent on monocrystalline silicon/stainless steel substrate. Some impact factors for pore characterization were investigated by means of Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-ray Diffraction (XRD). The results indicate that porous titanium film with 0.2μm to 2μm pore diameter was prepared. The pore diameter was almost unchangeable through changing the ratio of tetrabuty titanate in precursors and it gradually become bigger with the dosage of PEG increasing. The pulling times and sintering ramp rate have remarkable influences on film thickness and pore distribution, respectively.

H-39: Structure Property Relationship of Tannic Acid Based Copolymers for Anti-oxidant Infused Wound Dressing: Matthew Korey1; John Howarter1; 1Purdue University
    In early 1900’s, tannic acid was the main method used to treat acute, third-degree burn wounds. However, after the discovery that tannic acid (TA) was leeching into the bloodstream of patients and causing severe liver damage, its use in this therapy was discontinued. More recent studies have shown the effectiveness and selectivity through which the end groups of tannic acid can be chemically modified with acid anhydrides. In order to localize the tannic acid to the burn wound and to not allow it to leech into the blood stream, it was proposed that a tannic acid macromer would be generated by chemical modification of the end groups of tannic acid with methacrylic anhydride and then radically co-polymerized with hydroxyethyl methacrylate (HEMA), a bio-friendly polymer. The mechanical properties, pH stability, degradation and leeching of this copolymer into solution were studied and correlated with molecular structure and composition.

H-40: Structure Property Relationship Studies of Electron Beam Welded Dissimilar Steel to Fe-Al Alloy Joints: Soumitra Kumar Dinda1; Gour Gopal Roy1; Prakash Srirangam2; 1Indian Institute of Technology, Kharagpur; 2University of Warwick
    Electron beam welding (EBW) technique was used to perform dissimilar welding of plain carbon steel to Fe-7%Al alloy under three different weld conditions such as with beam oscillation, without beam oscillation and at higher welding speed. The effect of weld parameters on the microstructure and mechanical properties of dissimilar joints was studied using optical microscopy, SEM, EBSD, hardness, tensile and erichsen cup tests. Microstructure results show that the application of beam oscillation resulted in uniform and homogeneous microstructure compared to without beam oscillations and higher welding speed. Tensile test results show no significant difference in strength properties in all three weld conditions, but the ductility was found to be highest for joints with the application of weld beam oscillation. Erichsen cup test results show that the application of beam oscillation results in excellent formability as compared with other two conditions.

H-41: Effect of Bias Induced Microstructure on Mechanical Properties of Nanocrystalline ZrWN Coatings: P. Dubey1; S. Srivastava2; R. Chandra2; C. Ramana1; 1University of Texas at El-Paso; 2Indian Institute of Technology Roorkee
    In this work, hard nanocrystalline ZrWN coatings were sputtered at 200șC deposition temperature in the shed of various substrate bias (-20 V to -120 V). The effect of negative substrate bias on microstructure and hence on mechanical properties of nanocrystalline ZrWN coatings has been studied in details. The results indicate that the microstructure and morphology were significantly altered as the bias voltage goes up. A dense glassy structure, maximum compressive stress (8 GPa) and hence optimum mechanical properties (hardness~ 34 GPa, reduced elastic modulus ~ 145 GPa, wear resistance~ 0.23 and fracture toughness~ 2.25 MPa√m) of ZrWN coating have been obtained at -100 V bias voltage. The evident enhancement of mechanical properties can be achieved by proper control of bias induced microstructure and stress in the films.