Volume 49, Number 10--October 1997

Ten years ago, high-temperature superconductivity was first reported, creating headlines and inspiring research proposals around the world. Understandably, the enthusiasm of the experts coupled with images akin to that presented on this month's cover captured the imaginations of scientists and the general public alike. How far have these oxides come since they first levitated into our collective consciousness? Five papers in this issue of JOM attempt to answer that very question.

Click on the cover to see a full-page reproduction

JOM-e Logo JOM-e is a periodically presented all-electronic supplement to the conventional print version of JOM-e. Enhanced through the application of hyperlinks and/or other hypermedia features, the papers presented in JOM-e do not appear in print and are available only through TMS OnLine at the addresses shown below. The papers are, however, fully considered to be as much a part of JOM-e as the articles that appear in print. Beginning with the 1998 volume year, JOM-e will be published quarterly.

The Challenge of Precursor Compounds in the MOCVD of Oxides
Ren Xu
The technology of metalorganic chemical vapor deposition (MOCVD) for oxides has experienced explosive advances in the past ten years due to popular interests in oxide superconducting, ferroelectric, and dielectric materials. The characteristics of deposited oxide films show crucial dependence on the selection of precursor compounds, deposition temperature and environment, and kinetic factors such as the precursor partial pressure and flow rate. A simple classification of precursor compounds and discussion on their physical and chemical characteristics within the context of vapor deposition can be useful for MOCVD practitioners.

Research Summary:
The Thermocyclic Behavior of Differently Stabilized and Structured EB-PVD TBCs
U. Schulz, K. Fritscher, C. Leyens, M. Peters, and W.A. Kaysser
Thermal-barrier coatings are increasingly applied to hot components in gas turbines; the most prominent application processes are plasma spraying and electron-beam physical vapor deposition. Electron-beam physical vapor deposition provides distinctive coatings of a unique columnar microstructure. The main advantage of this structure is its superior tolerance against straining, erosion, and thermoshock, thus giving it a major edge in lifetime. Furthermore, cooling hole closure will be prevented and an aerodynamic design of the blades is maintained. This article outlines the interaction between chemical composition and microstructural evolution of zirconia-based thermal-barrier coatings and their respective lifetimes in cyclic burner-rig and furnace tests. Customizing the microstructure by adjusting processing parameters is emphasized. A structural-zone diagram is modified by interconnecting the influence of substrate rotation with the microstructural evolutions.

Research Summary:
The Solubility of Silica in Calcium Ferrite Slags
C.M. Acuña and A. Yazawa
In copper smelting processes, lime flux offers several advantages over silica; however, copper concentrates contain levels of silica that may impair the benefits of lime (i.e., formation of dicalcium silicate). To fully utilize the benefits of lime fluxing, the solubility of silica in the final slag must be investigated. The solubility of silica in calcium ferrite slags was investigated under different atmospheric conditions between 1,473-2,573 K.


High-Temperature Superconductivity--Ten Years After the Discovery [p. 11]
Paul J. McGinn

The Structural Conditions for High-Temperature Superconductivity [pp. 12-17]
M. Haller and R.L. Snyder

Reviewing Some Current Theories for High-Temperature Superconductors [pp. 18-23,50]
E. Dagotto

The Freeway Model: New Concepts in Understanding Supercurrent Transport in Bi-2223 Tapes [pp. 24-27]
G.N. Riley, Jr., A.P. Malozemoff, Q. Li, S. Fleshler, and T.G. Holesinger

Progress in the First Ten Years of HTS Film Growth [pp. 28-32]
Douglas B. Chrisey


Economic and Environmental Aspects of Producing Copper Chemicals [pp. 33,50]
Norbert L. Piret

The U.S. Production of Copper Chemicals from Secondary and By-product Sources [pp. 34-37,49]
P.B. Queneau and R.W. Gruber

The Production and Application of Cuprous Oxide and Cupric Hydroxide [pp. 38-39]
Adalbert Lossin and Franz-Josef Westhoff

Recovering Copper and Copper Chemicals from Spent Alkaline Etchant [p. 40]
T. Kawashima


Industrial Insight:
The Toyo Copper Smelter of Sumitomo Metal Mining [pp. 41-43,48]
Kozo Baba

Industrial Insight:
Making Improvements in Smelting Capacity at Onsan Copper Smelter [pp. 44-46]
Y.C. Kang and S.S. Park


Defining the Core Materials Curriculum [p. 10]
M.A. Crimp and A.D. Rollett


In the Final Analysis [p. 3]
News & Update [pp. 4-9]
Material Matters: Understanding Copyrights: A Glossary [pp. 47-48]
Meetings Calendar [pp. 57-60]
Consultants Directory [pp. 61-63]
Classifieds [pp. 61-63]
Retrospect [p. 64]


TMS News [pp. 53-56]

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