High-Temperature Corrosion and Materials Applications
High-Temperature Corrosion and Materials Applications

Author: George Y. Lai

Publisher: ASM International

Published: 2007-01-01

Total Pages: 469

ISBN-13: 1615030557

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George Lai's 1990 book, High-Temperature Corrosion of Engineering Alloys, is recognized as authoritative and is frequently consulted and often cited by those in the industry. His new book, almost double in size with seven more chapters, addresses the new concerns, new technologies, and new materials available for those engaged in high-temperature applications. As we strive for energy efficiency, the realm of high-temperature environments is expanding and the need for information on high temperature materials applications was never greater. In addition to extensive expansion on most of the content of the original book, new topics include erosion and erosion-corrosion, low NOx combustion in coal-fired boilers, fluidized bed combustion, and the special demands of waste-to-energy boilers, waste incinerators, and black liquor recovery boilers in the pulp and paper industry. The corrosion induced by liquid metals is discussed and protection options are presented.

Materials Compatibility With Uranium Fluorides at High Temperatures
Materials Compatibility With Uranium Fluorides at High Temperatures

Author: S. Anghaie

Publisher:

Published: 1996

Total Pages: 162

ISBN-13:

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The objective of an ongoing study being conducted by the Innovative Nuclear Space Power and Propulsion Institute (INSPI) at the University of Florida, is to find suitable materials for use in contact with uranium tetrafluoride from approximately 1200 to 3000 C. This temperature range encompasses both the liquid and gas phase of UF4. In this project ceramic materials were investigated which have been used in the fuel of nuclear reactors. These materials, if compatible with UF4, would be extremely valuable due to their very high melting temperatures, familiar chemistry, and well characterized nuclear properties. Experiments were conducted on thorium dioxide (ThO2) and uranium dioxide (UO2). Samples were exposed to liquid UF4 at 1100 C and to UF4 vaporized at above 1450 C. Exposures took place in a graphite crucible inside an evacuated quartz tube. An inductive heating system was used to heat the crucible and thereby the UF4. Use of the quartz tube allowed direct observation of the ongoing reactions. At the conclusion of each exposure samples of residual gases diluted with nitrogen were run through a gas chromatograph (GC) to determine which gases were released as corrosion products. Subsequent to each experiment remaining samples were weighed then photographed at 2.5x magnification. Power samples of the surface scales and the bulk samples were then prepared for x-ray diffraction analysis (XRD) to determine composition. Data from the GC and XRD were then correlated with equilibrium reaction product data obtained from F*A*C*T to determine the reactions present. Surface analysis of the samples was conducted using Scanning Electron Microscopy (SEM) to examine the scales formed at high magnification and Energy Dispersive X-Ray Spectroscopy (EDS), to qualitatively determine the elements present in various parts of the scales. Experiments with uranium dioxide showed that although UO2 does not react significantly with UF4, it does dissolve in liquid UF4 and apparently suffers from ablation when exposed to UF4 vapor. Thoria did react with UF4 in both the liquid and gas phase exposures, forming a mixture of uranium dioxide and uranium-thorium oxyfluorides.