Applications of Process Engineering Principles in Materials Processing, Energy and Environmental Technologies: An EPD Symposium in Honor of Professor Ramana G. Reddy: Materials Processing and Plasma Processing
Sponsored by: TMS Extraction and Processing Division, TMS Light Metals Division, TMS: Energy Committee, TMS: Hydrometallurgy and Electrometallurgy Committee
Program Organizers: Shijie Wang, Rio Tinto Kennecott Utah Copper; Michael Free, University of Utah; Shafiq Alam, University of Saskatchewan; Mingming Zhang, Arcelor Mittal; Patrick Taylor, Colorado School of Mines
Wednesday 2:00 PM
March 1, 2017
Location: San Diego Convention Ctr
Session Chair: Rauf Eric, University of the Witwatersrand
Plasma Processing of Thin Films for Data Storage and Future Non-Volatile Memory: Subhadra Gupta1; 1University of Alabama
New layered Heusler alloys have been discovered in the bulk form for eventual spintronic applications. We will briefly discuss the theoretical prediction of these half-metallic layered Heusler alloys and detail the experimental fabrication and characterization of the bulk and thin film forms of these materials. Characterization by X-ray diffraction, electron beam selected area diffraction, and local electrode atom probe will be presented. We will discuss the applications of these novel half-metallic materials to future memory applications, such as spin-torque transfer magnetic random access memory and hard disk drive thin-film read heads. We will also detail our experimental studies of bit-patterned media for future hard disk applications, utilizing two different types of block copolymers for patterning. A statistical Response Surface Methodology was used to optimize the patterning parameters for the bit-patterned perpendicular media, consisting of Co/Pd multilayers. Feature sizes as small as 10 nm have been achieved with this approach.
DuraStell PTA Cladding for Wear Application: Jack Zheng1; Robert Vasinko1; 1Kennametal
Cladding by plasma transferred arc (PTA) welding is widely used for enhancing the surface properties of a metallic component, in particular wear, high temperature and corrosion resistances. This paper presents the application of Kennametal Stellite PTA cladding technology, especially the DuraStell PTA process technique, for tungsten carbide composite cladding for boiler tube application. DuraStell PTA process gives low heat input to the substrate and fast deposition rate. The cladded boiler tube samples showed more uniform carbide dispersion in the cladding, less base metal dilution, and insignificant effect on the microstructure and mechanical properties of the substrate base metal, in comparison of the traditional PTA and other arc welding process.
Plasma Processing of Neodymium Oxide: Hunter Sceats1; Patrick Taylor1; 1Colorado School of Mines
This research discusses ongoing work towards the plasma-assisted reduction of neodymium oxide. Current industrial practice for reduction of the rare earth oxides necessitates the use of techniques such as molten salt electrolysis. In hopes of employing more environmentally benign methods, this work investigates the use of hydrogen as a reducing agent. Whereas molecular hydrogen gas is only capable of reducing the oxides of relatively noble metals, dissociated hydrogen radicals are much more chemically reactive and have the potential to reduce neodymium oxide. In this research, production of hydrogen radicals is achieved in a microwave discharge. Modeling of the apparatus and discharge is provided, as is a discussion of the real-time diagnostic techniques employed in the system. Initial efforts towards computational simulation of the solid state reactions are also presented, as well as preliminary experimental results.
Characterization and Feasibility Study of Thermoelectric CoSi2: Jacob Young1; Ramana Reddy1; 1University of Alabama
Cobalt silicides are known to have excellent electrical properties and good thermal stability at high temperatures. This study investigates the feasibility of CoSi2 as a high temperature thermoelectric material for energy recovery. The synthesis and phase analysis of bulk CoSi2 from elemental powders was investigated. Thermal conductivity, electrical resistivity, Seebeck coefficient, and figure of merit (ZT) were measured. Thermodynamic and kinetic studies were completed using DTA techniques. Finally, the thermoelectric capability of bulk CoSi2 was compared to literature examples of CoSi2 thin films and single crystals, as well as CoSi and other silicide-based thermoelectric materials.
3:20 PM Break
Production of SiMn-alloys by Natural Gas and Carbon Black: Xiang Li1; Merete Tangstad1; 1Norwegian University of Science and Technology (NTNU)
Currently, the main carbonaceous material for Mn-alloys production is solid carbon, i.e. coke, charcoal and petroleum coke, which is produced under massive CO2 emissions. Due to the easy purification, high carbon activity and low CO2 emissions, natural gas stands in the advantage status compared with conventional reducing agents. The aim of present project is to develop a new technology for production of Mn-alloys using natural gas as a source of carbon. Experiment results indicated that injection of CH4 gas into melted slag improved slightly the reduction of MnO and SiO2. However, the metal yield was far from the theoretical value duo to a relative low residence time of CH4 in the slag. Alternative approach was to use of carbon black as reductant, which was produced by CH4 decomposition. The preliminary experiment results showed a high reduction rate by using carbon black.
Effect of Flux Ratio on the Products of Self Propagating High Temperature Synthesis-Casting in WO3-Si-Al System: Sutham Niyomwas1; Tawat Chanadee1; 1Prince of Songkla University
Influence of flux CaO2-Al ratio on the SHS-casting reaction products in WO3-Si-Al system has been investigated in this study. Incorporation of CaO2-Al amounting to 1-5 wt% of total charge has been found to be adequate to form WSi2 intermetallic with a maximum hard-W5Si3 secondary phase. The micro-hardness of tungsten silicides intermetallic product increased significantly with CaO2-Al ratio. The as-SHS-casting products were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy dispersive x-ray (EDX) technique.
Effects of Mg on the Microstructure and Mechanical Properties of EH36 Shipbuilding Steel: Xiaodong Zou1; Dapeng Zhao1; Cong Wang1; 1Northeastern University
Recently, high heat input welding methods have gained engineering applications. However, increasing welding heat input usually leads to significant coarsening of austenite grains and formation of brittle microstructures, resulting in the reduced toughness of HAZ. It is expected to utilize oxide metallurgy to solve the problem by controlling the formation of fine inclusions. In prior studies, few studies focus on the evolution of microstructure during the whole process of steelmaking. For guiding industrial production, effects of 7ppm Mg on the evolution behavior of inclusions and microstructure in the EH36 ship steel after casting, rolling and welding are investigated. It is found that a large amount of fine inclusions are generated in the slab and plate after Mg addition, which refine the microstructure. After welding thermal simulation, it is found that in the heat input of 120kJ/cm Mg addition promotes nucleation of acicular ferrite, resulting in improved toughness of HAZ.
Enhanced Reducing Sugar Yield by Combining Alkaline Solution and Ionic Liquid Pretreatment of Biomass: Samuel Kassaye1; Kamal Pant1; Sapna Jain2; 1Indian Institute of Technology Delhi; 2Alabama State University
Imidazolium based ionic liquids (ILs) universal solvating properties have been exploited to dissolve bamboo biomass into reducing sugars under controlled temperature. With respect to overall sugar yield, experimental evaluation of pretreatment of bamboo biomass with alkaline solution and ionic liquid has been investigated. 1-butyl-3-methyl imidazolium chloride ([BMIM]Cl) was used as a pretreatment reagent to overcome the recalcitrant nature of lignocellulosic biomass by breaking the hydrogen bond network . The effect of pretreatment step on the properties of the original bamboo biomass was evaluated by FTIR, XDR, SEM, TGA and elemental analysis. Enhanced yield of reducing sugars from 30% for untreated biomass to 80% after pretreatment has been observed.