New papers that have been accepted for publication in the Journal of the American Ceramic Society are posted to “Early View” on the Wiley website and can be read even before the issue is printed. Below are summaries of selected papers currently available via Early View.
All members of The American Ceramic Society receive free online access to JACerS. To access any of the ACerS journals, or to become a member, visit www.ceramics.org.
Measurements of enthalpy of HfO2 by drop method in Bunsen type ice calorimeter. Credit: JACerS
Experimental Approaches to the Thermodynamics of Ceramics above 1500°C
Sergey V. Ushakov and Alexandra Navrotsky
In a special article, Ushakov and Navrotsky of the University of California at Davis review classic experimental approaches for the measurement of formation enthalpies and high-temperature enthalpy increments by the drop method as well as more recent developments that include mass spectrometric measurements of vapor pressures, pulsed laser relaxation methods for heat capacity and melting temperature determination, and high-temperature oxide melt solution calorimetry as applied to refractory compounds. They use studies of liquid immiscibility in the Zr(O)-UO2 system to introduce experimental determination of phase diagrams at high temperature. They also report a premelting phase transition in Y2O3 in oxygen from in-situ synchrotron X-ray diffraction study on levitated samples.
SEM images of the same region in porous synthetic cordierite before (left) and after (right) exposure at 1100°C for 24 h. These images provide evidence for microcrack healing in this material at elevated temperature. Credit: JACerS
The Thermal Expansion, Elastic and Fracture Properties of Porous Cordierite at Elevated Temperatures
Amit Shyam, Edgar Lara-Curzio, Amit Pandey, Thomas R. Watkins and Karren L. More
This Oak Ridge National Laboratory team used a double-torsion test between 20°C and 900°C to determine fracture toughness and slow crack growth of porous cordierite obtained from the walls of diesel particulate filters. The team also determined thermal expansion and elastic properties between 20°C and 1000°C.
Photograph of as-obtained glass. Credit: JACerS
Weidong Xiang, Haijun Zhao, Jiasong Zhong, Xinyu Yang, Yuqing Guo, Hongyan Luo and Xiaojuan Liang
These researchers from Wenzhou University and Tongji University in China used sol-gel method and atmosphere control to prepare sodium borosilicate glass doped with CuInS2 quantum dots. They report that 5- to 15-nanometer quantum dots in a tetragonal crystal system formed uniformly in the glass. They also report that the glass has excellent third-order optical nonlinearities, giving it potential applications for nonlinear optics.
(a) 3-D X-ray tomographical view and 2-D cross-sectional views at (b) low magnification and (c) high magnification. Credit: JACerS
Synthesis of a Homogeneously Porous Solid Oxide Matrix with Tunable Porosity and Pore Size
Lingling Zhang, Zhengping Mao, James D. Thomason, Siwei Wang and Kevin Huang
This University of South Carolina research team used a sacrificial template method to synthesize a homogeneously porous samarium-doped cerium matrix, where the porosity and pore size of the resultant porous matrix could be controlled by the volume fraction of sacrificial material, sintering temperature and monomodal pore distribution produced by molecular-level mixing of coprecipitating of the SDC and the NiO sacrificial material. The team proposes that this method is an alternative to tailoring properties for applications in catalysis, fuel cells and gas separation membranes.
SEM image showing partial wetting of the ceramic surface by Ag particles on the rim of a BCP ceramic. Credit: JACerS
Vapor Transport Sintering of Porous Calcium Phosphate Ceramics
Margarete Schlosser and Hans-Joachim Kleebe
Schlosser and Kleebe of Germany’s Technische Universitat Darmstadt used β-tricalcium phosphate and biphasic calcium phosphate, several halide atmospheres and water vapor, and vapor transport sintering to fabricate ceramic scaffolds with fully interconnected porosity. They report that they were able to adjust microstructure and phase composition by selecting appropriate precursor materials, additives and process parameters. They report that the use of AgCl as a sintering additive facilitates VTS and produces finely dispersed silver particles on the scaffold’s surface, which might provide antibacterial properties to implant material.
Map of hysteresis widths (Volts) extracted from 128 000 distinct hysteresis loops acquired from a hysteresis movie. Credit: JACerS
Bryan D. Huey, Ramesh Nath Premnath, Sungjun Lee and Nicholas A. Polomoff
These researchers from the University of Connecticut and Korea Research Institute of Standards and Science used a high-speed variation of scanning probe microscopy to investigate the nucleation and growth of individual ferroelectric domains. They report nucleation times and growth velocities indicate that domain nucleation and growth are uncorrelated but that domain switching dynamics strongly couple to film defects. They suggest that high-speed SPM imaging and in-situ activation, by, for example, voltage, provide an important method to study photovoltaics, thermoelectrics, batteries, fuel cells, multiferroics and phase change systems.
(a) TEM image of the composite with 5% boron nitride. (b) Selected area electron diffraction (SAED) pattern of composite with 5% boron nitride content. Credit: JACerS
Synthesis and Characterization of Chitosan/Boron Nitride Composites
Sudhir K. Kisku and Sarat K. Swain
Kisku (North Orissa University) and (Veer Surendra Sai University of Technology) of India used sonication to prepare chitosan/boron nitride composites with CuSO4/glycine chelate complex as catalyst. They report that the boron nitride was dispersed within the chitosan matrix through intercalation, that the thermal stability of the composite was increased compared with virgin chitosan, and that the oxygen permeability of the composite decreased substantially with increased boron nitride concentrations (making it a possible application in the packaging industry).
Top: bigger pores from burnt out of PMMA particles. Bottom: SEM showing the in-vitro osteoblast growth after 3 days on a scaffold-like HA/TCP coating. Credit: JACerS
Deposition of Micro-Porous Hydroxyapatite/Tri-Calcium Phosphate Coating on Zirconia-Based Substrate
Rumana Sultana, Jingzhou Yang and Xiaozhi Hu
These researchers from the University of Western Australia and China University of Geosciences used a hydroxyapatite slip-coating deposition and coating-substrate cosintering process to deposit scaffoldlike hydroxyapatite/tri-calcium phosphate coatings on strong zirconia substrates. They report that the composites have a bending strength higher than the upper strength limit of natural bones, making them a possible option for load-bearing bone implants.