Volume 79, Issue 10

The 12th International Conference on High Temperature Materials Chemistry (HTMC-XII) took place at the Vienna University of Technology, Austria, 17-22 September 2006. Previous conferences were held in 2000 in Juelich (Germany), and in 2003 in Tokyo (Japan). The conference was sponsored by IUPAC and organized by the Department of Inorganic Chemistry/Materials Chemistry of the University of Vienna together with the Austrian Chemical Society (GÖCH) and the Department of Materials Chemistry of the Vienna University of Technology. The local organizing committee was chaired by Profs. Adolf Mikula and Herbert Ipser of the University of Vienna. Special patronage was granted by the Austrian Federal Minister for Education, Science and Culture and by the mayor of Vienna. More than 150 participants from 25 countries worldwide came to Vienna to present their research in the field of high temperature materials chemistry and to interact with each other in a lively scientific discussion. A considerable number of scientists, especially from Russia and some Eastern European countries, had the chance to come to this conference for the very first time, partly due to partial financial support by the local organizers, for example, by reduced or waived registration fees. It was also a pleasure to see many young scientists who made new contacts with each other and with their senior colleagues from all over the world. The program contained nine plenary lectures, corresponding to the main topics, but also included two special lectures on topics of more general interest, such as "Do universities prepare for industrial careers" (by Knuth Consemüller, chairman of the Austrian Council for Science and Technology Development), and "The arts: What use to materials science" (by Mark Miodownik). The plenary lectures, with the exception of the lecture by Dr. Consemüller, are published in this issue. In addition, there were 51 oral presentations and 100 posters that were on display for the entire week. For this conference, IUPAC sponsored three poster awards, and the winners received a two-year subscription of Chemistry International , a copy of the IUPAC "Gold Book" as well as a certificate signed by the IUPAC president. The winners, as selected by an international jury, were Dario Manara of Italy ("The uranium-oxygen phase diagram at high temperature: Recent advances"), Yuriy Plevachuk of Ukraine ("Density and electrical conductivity of liquid Al-Fe and Al-Ni binary alloys"), and Jiři Popovic of the Czech Republic ("Thermodynamic optimization of the Ni-Al-W system"). The social program included a reception in the City Hall of Vienna, sponsored by the mayor of Vienna, as well as a conference excursion to the easternmost Austrian province, Burgenland, with visits to the small town of Rust on the shore of Lake Neusiedl and a guided tour through the Esterhazy Palace in Eisenstadt, the capital of Burgenland. This was followed by a string quartet concert with music by the Austrian composers Joseph Haydn (who had lived and worked in this particular palace for many years) and Wolfgang Amadeus Mozart (whose 250th birthday was celebrated in 2006). The excursion ended with a conference banquet in the state rooms of the palace. Judging from the comments of the participants, HTMC-XII was a big success, and many of the scientists promised to come back to the next meeting, HTMC-XIII. Most probably this will be held in 2009 in California, USA, organized by Prof. Alexandra Navrotsky of the University of California at Davis. Adolf Mikula and Herbert Ipser Conference Editors

In ancient societies, there was no arts/science split. The development of materials was driven both by aesthetic and technological goals. At the end of the 19 th century, things changed dramatically. Scientists started being able to analyze composition, detect structure, and make a link between structure and properties. The subsequent 20 th -century revolution in new materials changed almost all aspects of human activity. However, it was not without serious side-effects, the first of which has been that the materials science community has willingly marginalized itself. The second is the eradication of interest in the sensual and aesthetic properties of materials, and thus the banishment of the creative urges that arrive via the senses. This paper discusses these issues, and suggests that collaboration with the materials arts community offers exciting new challenges and could create an intellectual community that is not just more culturally and ethically aware, but also nurtures more innovative science.

Aerodynamic levitation is a simple way to suspend samples which can be heated with CO 2 lasers. The advantages of this technique are the simplicity and compactness of the device, making it possible to integrate the device easily into different kinds of experiments. In addition, all types of sample can be used, including metals and oxides. The integration of this technique at synchrotron and neutron sources provides powerful tools to study molten materials.

Enthalpies of formation of Al-Ni-X (X: Fe, Ru, Pd, Pt, and Cu) alloys were measured by high-temperature calorimeter and compared with the calculated value from Miedema's model and interpolation models. The interpolation models generally provide better prediction than Miedama's model. No one interpolation model generated superior predictions. Lattice parameters of B2 phase compounds were determined by X-ray diffraction (XRD). The atomic volumes in the Al-Ni-Fe system were calculated and show that Fe substitutes preferentially on the Al sublattice. The heat content of Al 0.5 Ni 0.2 Ru 0.3 and Al 0.5 Ni 0.35 Cu 0.15 at high temperature was obtained, and the results are in good agreement with those heat capacities estimated by the Neumann-Kopp rule.

The defect chemistry of different ordered intermetallic compounds with the A 3 B stoichiometry was investigated. Three groups were distinguished according to their crystal structure: L1 2 compounds (Ni 3 Al, Ni 3 Ga, Pt 3 Ga, Pt 3 In), D0 19 compounds (Ti 3 Al), and D0 3 compounds (Fe 3 Al, Ni 3 Sb). Statistical-thermodynamic models were derived based on a Wagner-Schottky approach, and the calculated activity curves (thermodynamic activity vs. composition) were compared with experimental activity data. In this way, we attempted to obtain at least estimated values for the energies of formation of the different types of point defects present in the corresponding compound, both as configurational defects (which are responsible for nonstoichiometry) and as thermal defects. In the majority of cases, thermodynamic activities had to be determined experimentally in the present study, using either an emf method with a solid electrolyte (Ni 3 Ga, Pt 3 Ga, Pt 3 In, Fe 3 Al) or a Knudsen cell-mass spectrometric method (Ni 3 Sb).

An up-to-date summary of our coupled macroscopic (lattice parameter, a 0 ) and microscopic (Mössbauer) studies on the entitled systems is given, shedding new light on the basic phase and structure properties of these technologically important, highly defective oxides. Through these studies, the intermediate-pyrochlore (P)-based local structure nature of the so-called stabilized-zirconia (SZ)- and stabilized-hafnia (SH)-type defect-fluorite (DF) phases in the M 4+ = Zr and Hf systems seems to be almost unambiguously established with different (from the conventional) approaches: These are (1) the presence of a broad lattice parameter ( a 0 ) hump over the extended stabilized cubic DF region ( y = ~0.3-~0.7); (2) the microscopic 151 Eu-Mössbauer evidence of Eu 3+ isomer shifts (ISs) showing characteristic V-shaped minima around the ideal-P area ( y ~ 0.50) for both the M 4+ = Zr and Hf systems; and (3) rich 155 Gd-Mössbauer data on the Zr 1- y Gd y O 2- y /2 system [IS, quadrupole splitting (QS), line width, peak height, and relative absorption area (RAA)], revealing detailed features of its ordered P-disordered DF phase and structure relationships. These results are discussed with reported basic-property data of these systems.

Results of the comprehensive experimental and computational phase studies of the systems ZrO 2 -REO 1.5 (RE = La, Nd, Sm, Gd, Dy, Yb) are summarized. Various experimental techniques, X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM), differential thermal analysis (DTA), and high-temperature calorimetry are employed to study the phase transformation, phase equilibria between 1400 and 1700 °C, heat content and heat capacity of the materials. A lot of contradictions in the literature are resolved, and the phase diagrams are reconstructed. Based on the experimental data obtained in this work and literature, the systems ZrO 2 -REO 1.5 are thermodynamically optimized using the CALPHAD (CALculation of PHase Diagram) approach. Most of the experimental data are well reproduced. Based on the present experiments and calculations, some clear characteristic evolutions with the change of the ionic radius of doping element RE +3 can be concluded.

The paper discusses the scientific understanding of the role of interfacial phenomena in joining of dissimilar materials using liquid-phase-assisted processes. From the example of the Sn-alloy/Cu system, it is demonstrated that interaction in the liquid solder/substrate couples is accompanied by a number of complex interfacial reactions leading to significant changes in the structure and chemistry of interfaces (solder/substrate, solder/environment, substrate/environment) and remaining solder layer that finally influence the mechanical properties of solder joints. The experimental data on wetting behavior, interface characterization, and mechanical properties of different solder/metal substrate couples are analyzed in order to display the role of such factors as time and temperature of interaction, environment (protective atmosphere, flux), presence of oxide films on interfaces, alloying additions to a solder, formation of interfacial phases, and porosity.

Continuous development of light sources is required from energy-saving considerations (enhancing luminous efficacy) and an environmental protection point of view (lamps that are easy to recycle or made of environmentally friendly materials). This paper summarizes some of the recent results of materials science research with special attention to chemical aspects. The results will be cited from the field of discharge chemistry, electrodes, ceramics, and other materials.

Established IUPAC recommendations for the representation of configuration are reviewed briefly, and then methodologies are examined for dealing with regular polyhedra that are typically used when working with coordination numbers greater than 6. More than one method is available and can be used for many such geometries, but the deviations from regular polyhedral geometries that are typically found in such molecules can make it difficult to arrive reproducibly at the same description for a complex using purely objective criteria. Recommendations are made for some geometries of coordination numbers 7, 8, and 9, but not for higher coordination numbers.

This document defines terms related to the structure and processing of inorganic, polymeric, and inorganic-organic hybrid materials from precursors, through gels to solid products. It is divided into four sections - precursors, gels, solids, and processes - and the terms have been restricted to those most commonly encountered. For the sake of completeness and where they are already satisfactorily defined for the scope of this document, terms from other IUPAC publications have been used. Otherwise, the terms and their definitions have been assembled in consultation with experts in the relevant fields. The definitions are intended to assist the reader who is unfamiliar with sol-gel processing, ceramization, and related technologies and materials, and to serve as a guide to the use of standard terminology by those researching in these areas.