Characterization of Minerals, Metals, and Materials: Clays and Ceramics
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Shadia Ikhmayies, Al Isra University; Bowen Li, Michigan Technological University; John Carpenter, Los Alamos National Laboratory; Jian Li, CanmetMATERIALS; Jiann-Yang Hwang, Michigan Technological University; Sergio Monteiro, Military Institute of Engineering ; Firrao Donato, Collegio Universitario, Italy; Mingming Zhang, ArcelorMittal Global R&D; Zhiwei Peng, Central South University; Juan P. Escobedo-Diaz, UNSW Australia; Chenguang Bai, Chongqing University; Eren Kalay, METU; Ramasis Goswami, Naval Research Laboratory; Jeongguk Kim, Korea Railroad Research Institute

Monday 8:30 AM
February 27, 2017
Room: 32B
Location: San Diego Convention Ctr

Session Chair: Bowen Li, Michigan Technological University; Carlos Fontes Vieira, UENF

8:30 AM  
Effect of Skin-Core Hierarchical Structure on Dielectric Constant of Injection Molded and Cast Film Extruded Liquid Crystalline Polymer: Mark Shooter1; Anil Saigal1; Michael Zimmerman1; 1Tufts University
    Radio Frequency technology demands advanced packaging materials for low-loss operation. While, current ceramic materials can provide acceptable dielectric performance, liquid crystalline polymers (LCPs) have emerged as an alternate material capable of exceeding current performance with cost efficient manufacturing. In high frequency applications, low dielectric constant (Dk) is a critical material characteristic. LCP consists of a highly crystalline, non-polar mesoscopic structure resulting in low and stable dielectric properties up to 100 GHz. Processing LCPs introduces shear and hierarchical macroscopic structure further driving anisotropy. This research compares dielectric properties in the flow (machine) and transverse direction of injection molded (~ 1.6 mm) and extruded LCP film (~ 0.115 mm). The cross-section skin-core morphology is studied and dielectric properties are examined with the removal of the highly oriented skin layer from the aforementioned processes. Extruded LCP film experienced a reduction in Dk in both the directions studied with the skin layer removed.

8:50 AM  
Aging Behaviour in Ni0.5CoxMn2.5-xO4 (x=0.5, 0.8 and 1.1) Thermistors: Gökhan Hardal1; Berat Yüksel Price1; 1Istanbul University
    Negative temperature coefficient (NTC) thermistors is required to have the electrical stability under external factors for many domestic and industrial applications. The aging phenomenon of NTC thermistors can be described as the increasing in electrical resistance of materials under thermal stress with time. In this study, Ni0.5CoxMn2.5-xO4 (x=0.5, 0.8 and 1.1) ceramics were fabricated by the conventional solid-state reaction method. The powder mixture of high purity manganese, cobalt and nickel oxides was ball-milled for 5 hours. The powders were calcinated at 900oC for 2 hours. The samples were sintered at 1100oC for 5 hours in air. To investigate the effect of the aging process, the samples were held at 150oC for 400 hours. Aging in the samples were calculated by the following equation; ∆R/R0 = (R − R0)/R0 in which R0 is the resistivity at 25oC before the aging test, and R is the resistivity at 25oC after aging test.

9:10 AM  
Adsorption of Lead from Aqueous Solutions to Bentonite and Composite: Zhu Shu Jing1; Ying Qin2; 1Michigan Technological University; 2Wuhan University of Technology
    The characterization of adsorption of natural and composite bentonite in lead aqueous solution has been studied. The results showed that adsorption of both natural and composite bentonites strongly depended on the pH values of the solution. At lower pH values, the mechanisms that govern the adsorption of bentonites were dissolution of crystal structure and competition between the metal ions and the H+.

9:30 AM  
Fabrication of Transparent Lanthana-doped Yttria Ceramics by Spark Plasma Sintering: Esin Korkmaz1; 1Istanbul Technical University
    Rapid densification of yttria ceramics with 4% mol, 7% mol and 10% mol La2O3 sintering aid via spark plasma sintering at relatively low temperature of 1300°C for 35 minutes at 50 MPa initial pressure and 100MPa final pressure in addition with post-annealing was at 1050 ºC for 6 hours in air was attempted. Both undoped and La2O3-doped bodies exhibited cubic phase, densification during SPS did not involve any phase transformation. Microstructure, hardness and fracture thoughness , optical in-line transmittance properties were analysed. The highest hardness value was recorded to be 7.01±0.38 GPa with 10% mol La2O3 doping, and 0.84MPam1/2 fracture toughness was measured with 4% mol La2O3 doping. The highest transmittance with a value of 60.7% at a wavelength of 2000 nm was obtained for the undoped yttria ceramics.

9:50 AM  
Microstructure and Mechanical Properties of Silicon Doped Boron Carbide: Luoning Ma1; Fatih Toksoy2; Kelvin Xie1; Kanak Kuwelkar2; Richard Haber2; Kevin Hemker1; 1Johns Hopkins University; 2Rutgers University
    Boron carbide, with its low density and superior hardness, is a promising material for personal armor applications. However, boron carbide is difficult to densify and generally exhibits poor fracture toughness. In this work, we overcame both challenges by using Si as the sintering aid. Fully dense samples were achieved by sintering B4C powder with 10 wt.% Si using spark plasma sintering. The addition of Si substantially lowered the sintering temperature. Moreover, Si reacted with free carbon, the oxide layer on the B4C powders to form ultrafine-grained SiC and SiO2. These phases distributed uniformly in the microstructure, facilitating densification by closing up of nano-pores, and improving both the hardness and fracture toughness. Also, we note that Si did not diffuse into and decompose the boron carbide grains. Instead it appears that carbon from graphite dies diffused into boron carbide and reacted with Si to form SiC.

10:10 AM Break

10:25 AM  
Synthesis and Characterization of Textured BCZT Ceramics Prepared by Molten Salt Synthesis Method: Jai Shree K1; Chandrakala E1; Dibakar Das1; 1University of Hyderabad
    Lead based and lead-free piezoelectric materials are well known for various sensor, actuator and transducer applications. Texture engineering has been utilized as an effective method to enhance the performance of piezoelectric ceramics by optimization of the microstructural features, which includes grain size, grain orientation and grain texture. In the present investigation lead-free piezoelectric BCZT templates have been prepared using molten salt synthesis by varying heating temperatures. The template powders were added to BCZT precursor powders with varying mole percentages. Further, these powders were compacted and sintered to achieve bulk dense ceramics. Phase and texturing of the sintered samples will be characterized by XRD and electron back scattered diffraction (EBSD) analysis. The piezoelectric properties (d33, g33, kp) will be measured as a function of varying BCZT templates and will be compared with the BCZT ceramics with random grain orientation.

10:45 AM  
Mechanical Analysis of Artificial Stone Produced with Glass Waste in Polymeric Matrix: Lucas Martins1; Carlos Maurício Vieira1; Elaine Carvalho1; Sérgio Monteiro2; 1UENF; 2IME
    This work is a study of a specific artificial stone, for interiors coverings, using as load waste glass from the industries of glass manufacture, in Vitória, Espirito Santo, Brazil. Through an experimental methodology, were studied the physical and mechanical properties of composites tiles with matrix of 25% epoxy with addiction of 75% of glass waste as load in a specific range of particle sizes. The tiles were produced in a steel mold, under compression. The results reveals the composite as a promising material to replace marble, as a cheap and moderately resistant artificial stone.

11:05 AM  
Phase Transformation of Andalusite-Mullite and Its Roles to Microstructure and Sinterability of Refractory Ceramic: Bowen Li1; Mengsheng He1; Huaguang Wang1; 1Michigan Technological University
    Andalusite is special for the production of refractory ceramics due to its unique property to automatically decompose into mullite and silica during heating at high temperature, which plays a critical role for the effective applications of andulusite. This study investigated the microstructural characteristics and sinterability of andalusite powder during high temperature. The andalusite green body was prepared at 20MPa, then fired at 1150~1450°C. The microstructures and mechanical strengths of the sintered ceramics were studied by compressive test, XRD, and SEM. The results showed that newly born mullite appeared as rod-like microcrystals and dispersed around the initial andalusite. At 1150ºC, the mullitization of andalusite was started, but completed until fired at 1450ºC. The compressive strength of the ceramics increased from 93.7 to 294.6 MPa while increasing the fire temperature from 1150ºC to 1450ºC. Meanwhile, the bulk density of the ceramics was only slightly changed from 2.15 g/cm3 to 2.19 g/cm3.

11:25 AM  
Structural Characterization of LaxSr1-xCoO3 (LSC 113) / (LaxSr1-x)2CoO4 (LSC 214) Hetero-Interface Cathode for Intermediate Temperature Solid Oxide Fuel Cells: Dogancan Sari1; Eren Kalay1; Tayfur Ozturk1; 1METU
    The solid oxide fuel cells have been studied extensively in last few decades due to their efficient energy conversion abilities. The modification and development of new cathode materials is crucial to increase the performance and life time of SOFCs. Oxygen reduction reaction and diffusion of oxygen ions through the cathode are two consecutive processes taking place in the cathode. Low kinetics of these processes are the major part of performance loss. In order to decrease the cost, increase the performance and life time of SOFCs, the kinetics of cathode related steps should be increased. Recently, the hetero-interface structures (like LSC 113 – LSC 214) have shown promising enhancement (1000–10000 times faster) at 500⁰C while the reasons are not clearly solved. In this study, the reasons of this enhancement are investigated with the help of in-situ x-ray analysis at 500C and detailed TEM analysis for LSC 113/214 hetero-interface structure.

11:45 AM  
Production and Characterization of Magnesium Aluminate Spinel (MgAl2O4) Ceramics with Ligth Transmission by Spark Plasma Sintering: Seyran Saridas1; Filiz Sahin1; 1Istanbul Technical University
    Transparent MgAl2O4 spinel ceramics were produced by spark plasma sintering (SPS) method from stoichiometric mixture of MgO and Al2O3 powders. The powder mixture was spark plasma sintered without sintering aid and with B2O3 additive separately at same temperatures (between 1250 °C and 1350 °C for 20 minutes) to investigate effect of dope on optical and mechanical properties. Transparent polycrystalline MgAl2O4 spinel was obtained with an in-line transmission of 65% for 550 nm (visible) and 85% for 1000 nm (IR) wavelengths. For optical characterization, the in-line transmission, Tin, was measured by spectrophotometer in the visible and near-IR-wavelength ranges. The effect of additive on density/relative density were examined by Archimedes method while the hardness values were obtained by Vickers indentation technique. The microstructures of sintered spinel ceramics were determined by scanning electron microscopy (SEM) and phase identification was performed by X-ray diffractometry (XRD).