Engineering Commons^™

Experimentation Of Abrasion Erosion At High Temperature For Concentrated Solar Power Systems, Tessa Mei-Lin Fong

Boise State University Theses and Dissertations

Concentrated solar power (CSP) is an alternative and sustainable way to produce energy. Studies have shown that running these plants at high temperatures above 700°C can increase the thermal efficiency in heat transfer. Molten salt is usually used as the heat transfer medium but cannot be used due to its low maximum temperature and high freezing point. Running these plants at high temperature brings up the concern of erosion and oxidation. Abrasion erosion occurs through the interaction of particles and material. The goal of this research is to understand material degradation due to abrasion erosion to understand the durability of …

Characterization Of Zirconium Oxides Part I: Raman Mapping And Spectral Feature Analysis, Corey M. Efaw, Jordan L. Vandegrift, Michael Reynolds, Samuel Mcmurdie, Brian J. Jaques, Hui Xiong, Michael F. Hurley

Materials Science and Engineering Faculty Publications and Presentations

Raman mapping of sectioned zirconium cladding oxides was performed to analyze different spectral features before and after breakaway, as well as between zirconium and its alloys Zr-2.65Nb, Zry-3, and Zry-4. Oxide phase composition, or percent tetragonality, was defined to compare tetragonal to monoclinic zirconia. Percent tetragonality was spatially mapped to support distinction of zirconia phase distribution. A tetragonal-rich layer was seen at the metal/oxide interface, while post-breakaway samples exhibited increased amount of tetragonal phase in the bulk of their oxides. Spatial mapping of spectral peak location and half-width at half-maximum was accomplished to distinguish differences in stability mechanisms of tetragonal-rich …

Oxidation Behavior Of Welded Zry-3, Zry-4, And Zr–1nb Tubes, Jordan Vandegrift, Clemente J. Parga, Ben Coryell, Darryl P. Butt, Brian J. Jaques

Materials Science and Engineering Faculty Publications and Presentations

The Transient Reactor Test (TREAT) facility is a research reactor designed to simulate rapid transients to test new fuel designs. TREAT's cladding is exposed to unique conditions compared to normal water reactors. These conditions include: exposure to air at high temperatures (≥600 °C), rapid heating (≈700 °^C/_s), and cladding geometry that includes chamfers and welds. This work investigates the effects of chamfering and welding on the oxidation behavior of zirconium alloys (Zircaloy-3, Zircaloy-4, and Zr–1Nb). Tube specimens were examined under isothermal and transient conditions in dry and humid air. The effect of weld type (tungsten inert …

Oxidation Behavior Of Zirconium, Zircaloy-3, Zircaloy-4, Zr-1nb, And Zr- 2.5nb In Air And Oxygen, Jordan L. Vandegrift, Patrick M. Price, John-Paul Stroud, Clemente J. Parga, Isabella J. Van Rooyen, Brian J. Jaques, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

The Transient Reactor Test (TREAT) facility at the Idaho National Laboratory currently utilizes a legacy Zircaloy- 3 cladding, which is no longer commercially available. TREAT is air cooled and routinely operates at temperatures well above that of traditional reactor designs. This study investigates the oxidation behavior of pure zirconium and its alloys (Zircaloy-3, Zircaloy-4, Zr-1Nb, Zr-2.5Nb) in Ar+20%O₂ and N₂+20%O₂ atmospheres at temperatures ranging from 400–800 °C to determine which alloy should be implemented as TREAT's cladding. While the oxidation behavior of zirconium based cladding materials has been extensively documented, this study focuses on direct comparison …

High Temperature Oxidation Kinetics Of Dysprosium Particles, Brian J. Jaques, Darryl P. Butt

Materials Science and Engineering Faculty Publications and Presentations

Rare earth elements have been recognized as critical materials for the advancement of many strategic and green technologies. Recently, the United States Department of Energy has invested many millions of dollars to enhance, protect, and forecast their production and management. The work presented here attempts to clarify the limited and contradictory literature on the oxidation behavior of the rare earth metal, dysprosium. Dysprosium particles were isothermally oxidized from 500 to 1000 °C in N₂–(2%, 20%, and 50%) O₂ and Ar–20% O₂ using simultaneous thermal analysis techniques. Two distinct oxidation regions were identified at each isothermal temperature …

An Intrinsic Model For Graphite Oxidation And The Effects Of Microstructural Features On Apparent Rate, Joshua J. Kane

Boise State University Theses and Dissertations

The very high temperature reactor (VHTR) is the latest generation of high-temperature gas-cooled reactors (HTGR). The VHTR has higher outlet temperatures than a traditional HTGR with outlet temperatures up to 1000 °C. This high outlet temperature permits emissions-free process heat in the form of high-quality steam for high temperature industrial applications. Moreover, the high temperatures of the reactor could potentially be used for hydrogen production from water or high efficiency electrical power production (~50% efficiency of thermal to electrical power conversion).

The VHTR is designed to employ helium as its coolant and uses graphite for its neutron moderator and as …

Kinetics And Mechanisms Of Titanium Wire Oxidation, Tanmay P. Engineer

Boise State University Theses and Dissertations

The kinetics and mechanisms of oxidation of titanium wire were assessed using a large test matrix in Ar-20% O₂ at 800 to 1200°C, and N₂-20% O₂ at 1000°C, for 0.5 to 24 hours. The effects of geometry on oxidation were evaluated by investigating the behavior of six high purity Ti wires with diameters varying from 50 to 2000 μm, with an objective of producing hollow TiO₂ tubes.

Oxidation behavior was characterized by measuring oxide thicknesses and morphology by optical microscopy, and the phases were characterized using a combination of SEM and TEM. The kinetics was …

Effects Of Crystallographic Orientation On The Early Stages Of Oxidation In Nickel And Chromium, Louis P. Bonfrisco, Megan Frary

Materials Science and Engineering Faculty Publications and Presentations

Surface orientation plays an important role in the oxidation behavior of single crystals where studies have found the relative oxidation rates for surfaces with different orientations. However, most materials are polycrystalline and contain myriad orientations that contribute to the overall oxidation process. Here we determine the effects of orientation on the early stages of oxidation behavior as a function of surface orientation for polycrystalline nickel (face-centered cubic) and chromium (body-centered cubic). After high temperature oxidation, the oxide topography is characterized using optical profilometry and the underlying microstructure is characterized with electron backscatter diffraction (EBSD). By correlating results from EBSD and …