Phase Stability in Extreme Environments: Corrosion and Oxidation in Extreme Environments
Sponsored by: TMS Structural Materials Division, TMS Materials Processing and Manufacturing Division, TMS: Corrosion and Environmental Effects Committee, TMS: Nuclear Materials Committee, TMS: Phase Transformations Committee
Program Organizers: Andrew Hoffman, Catalyst Science Solutions; Kinga Unocic, Oak Ridge National Laboratory; Janelle Wharry, Purdue University; Kaila Bertsch, Lawrence Livermore National Laboratory; Raul Rebak, GE Global Research
Wednesday 8:30 AM
March 22, 2023
Room: 28C
Location: SDCC
Session Chair: Kinga Unocic, Oak Ridge National Laboratory; Xiao-Xiang Yu, Novelis
8:30 AM
High Temperature Oxidation of CrAl Coated Accident Tolerant Fuel Cladding: Sung Eun Kim1; Dae Ho Kim1; Hyun-gil Kim1; 1Korea Atomic Energy Research Institute
After Fukushima accident, Accident Tolerant Fuel(ATF) cladding has been developed with purpose of improving a resistance to hydrogen explosion by retarding excessive hydrogen generation under accident environment. Zr alloys underwent rapid oxidation and excessive heat was released over 900°C and this resulted in hydrogen explosion. By enhancing of oxidation resistance, extended time to cope with accident situation can be achieved. CrAl exhibits superior oxidation and corrosion resistance required for stable operation of a nuclear power plants. Hence, we have been working on an improvement of oxidation resistance by Cr-Al coating on zircaloy cladding using AIP method. This work focuses on high temperature oxidation of CrAl coating layer of ATF cladding. CrAl coated claddings were systemically prepared using Arc Ion Plating Method(AIP) method. Thermogravimetric analysis(TGA) tests were carried out under high temperature steam condition. Optical and microstructural analysis were employed to investigate the properties after the test.
8:50 AM
Steam Oxidation Behavior of Environmental Barrier Coatings: Mackenzie Ridley1; Ken Kane1; Bruce Pint1; 1Oak Ridge National Laboratory
Environmental barrier coatings (EBCs) are required for application of SiC ceramic matrix composites (CMCs) as components in combustion turbines to achieve increased efficiencies from higher fuel burn temperatures. EBC research has often focused on Yb2Si2O7 EBCs due to its high-temperature phase stability, steam resistance, and thermal expansion match with SiC. In this work, various EBC chemistries were deposited onto SiC and cycled in high-temperature steam environments to determine oxidation resistance above 1250°C. Relationships between EBC chemistry, coating thickness, thermally grown oxide microstructure, and eventual coating spallation will be addressed. This research was funded by the Advanced Turbine Program‚ Office of Fossil Energy‚ Department of Energy.
9:10 AM
Cyclic Oxidation Behavior of Novel Ni-based Superalloys: Richard Oleksak1; Martin Detrois1; Paul Jablonski1; 1National Energy Technology Laboratory
Oxidation resistance is an important requirement for Ni-based superalloys used in a variety of high temperature applications. Herein the oxidation performance was assessed for a new class of polycrystalline gamma-prime strengthened superalloys designed to have a gamma matrix with high configurational entropy, with alloy compositions of (wt%) Ni-20Co-13Cr-6Fe-4Al-3W-2Mo-(4-x)Nb-(x)Ti, where x = 0, 1 ,2. The cyclic oxidation behavior and the effect of Nb and Ti contents was assessed through exposure to dry air at 800 °C for 3,500 hours. The alloys were found to be borderline chromia/alumina formers, exhibiting good oxidation resistance relative to commercially available materials of similar composition. While all alloys formed alumina scales initially, only the alloy with the lowest Ti/Nb ratio retained an alumina scale for the duration of the exposure. The other alloys transitioned to chromia scale growth, where the growth rates increased with higher Ti/Nb ratios. The mechanisms driving this oxidation behavior are discussed.
9:30 AM Invited
The Morphological Stability and Non-equilibrium Growth of Passive Oxide Films: Rohit Ramanathan1; Peter Voorhees1; 1Northwestern University
Understanding the kinetics of passive oxide formation and breakdown has been an ongoing problem for corrosion scientists for several decades. A model for the formation of a passive oxide film on a metal that is an extension of the Point Defect Model (PDM) will be presented. A linear stability analysis of the moving metal-oxide and oxide-solution interfaces shows that, depending on the parameters, the passive film may be unstable to morphological perturbations of the film interfaces, leading to nonplanar films and potentially the formation of a pit in the oxide. The non-equilibrium thermodynamics at stationary and moving oxide interfaces will also be discussed. We show that non-equilibrium cation concentrations are possible at a stationary oxide interface due to large fluxes of cations and vacancies through the interface.
10:00 AM Break
10:20 AM
Corrosion Behavior of Co-Fe4Mn4Nb4Si2B14, Fe49Co49V2, and Fe82Cr18 Alloys in Venusian Environment: Yuankang Wang1; Alex Leary2; Paul Ohodnicki1; 1University of Pittsburgh; 2NASA
The planetary exploration on Venus was hampered by its hostile surface environment (mostly of CO2 and N2 as well as traces of SO2, H2O, CO, OCS, HCl, HF, and H2S), high temperature and high pressure. For successful exploration on Venus, it is critical to understand corrosion behavior of materials in Venusian environment. This project investigated three candidate magnetic materials used in fabricating inductors and transformers, Fe82Cr18, Fe49Co49V2, and Co-Fe4Mn4Nb4Si2B14, exposed to Venusian atmosphere. The materials after exposure were characterized by XRD, SEM, EDS and TEM. The results indicates that Co-rich sulfides and Fe-rich sulfites are main corrosion products of materials with high Co and Fe content, respectively. Fe82Cr18 exhibits best corrosion resistance because of the formation of continuous protective Cr-rich scale on the surface during initial stage of corrosion. This protective scale prevents further corrosion by impeding the outward diffusion of metallic elements and inward diffusion of corrosive gas molecules.
10:40 AM
Surface Roughness and Oxidation Kinetics in Ni-based Single-crystal Superalloys: Aidan O'Donnell1; Jean-Briac le Graverend1; 1Texas A&M University
It is already known that surface roughness has a tremendous effect on fatigue, but there is also an effect on oxidation kinetics. Ni-based single-crystal Samples with different surface roughness ranging from 0.09 to 2.5 microns were tested at 1050C in a thermogravimetric analyzer (TGA) for 100h. it was revealed that the oxidation kinetics depends on the surface roughness in a non-linear manner, which was attributed to a coupling between the oxidazing molecule size and the surface profile.
11:00 AM
Ab initio Simulations to Investigate Oxidation in Ni-based Single-crystal Superalloys: Aidan O'Donnell1; Tahir Cagin1; Jean-Briac le Graverend1; 1Texas A&M University
Single-crystal superalloys operate at high temperatures, and their performance depends on factors, such as the concentration of minority elements, surface chemistry, and structure, in particular their effects on oxidation energetics and kinetics. We employ a systematic density functional method to study and examine the alloying energetics as a function of the concentration of binary alloys with Al, Cr, and Co. The energies of mixing are determined using Vienna Ab initio Simulation Package for distinct concentrations of the minority element. Using Boltzmann Statistics, we compute the probability weights of the particular configurations. We made use of these structures to develop models for different low index surfaces and calculated their surface formation energies. To study the oxidation energetics and kinetics, we conduct DFT calculations on the most likely surface models. Our objective is to understand the influence of crystallographic orientations and concentrations of doping elements, surface roughness and vacancy concentration on oxidation.
11:20 AM
Understanding the Effect of SO2/SO3 Gaseous Environments on the Mixed Deposit-induced Degradation of Advanced Alloys: Atharva Chikhalikar1; David Poerschke1; 1University of Minnesota, Twin Cities
Understanding interactions between the ingested deposits and the superalloys/bond coat components is critical for improving the performance and lifetime of next-generation turbine materials. Recent evidence suggests that mixed multi-cation, multi-anion (oxide-sulfate) deposits can accelerate the degradation of alloys at temperatures greater than 950 °C. However, the interplay between the alloy chemistry, gas atmosphere, and deposit composition have been understudied. This work systematically explored the effect of the air - 10 ppm SO2/SO3 environment on the degradation of two advanced alloys in the presence of multiple deposit chemistries. The alloys were pre-oxidized at two different time scales to analyze the effect of thermally grown oxide thickness on the degradation. Samples were characterized using an automated image analysis approach to compare the degradation intensity under varying parameters. The results enhanced our understanding of the effect of the gas atmosphere on the degradation of alloys and its implications for developing next-generation turbine superalloys.
11:40 AM
Investigation of Alloy Elements on the Enhanced Oxidation Behavior of Nanocrystalline Alloys: Saurabh Sharma1; Kris Darling2; Kiran Solanki1; 1Arizona State University; 2Army Research Laboratory
The high temperature mechanical response of nanocrystalline Cu-Ta alloys have been the recent focus of several fundamental studies. Such studies have included the high temperature creep response, high dose radiation damage immunity, high thermal conductivity and prolonged (10,000s hrs) high temperature stability. Despite the extraordinary property-set, stable passivating oxides have not been developed within the family of Cu-Ta alloys, prohibiting them in applications such as next generation heat exchangers. Here we report engineering the environmental degradation behavior of the new oxidation resistant Cu-Ta-Cr alloys, for the first time. Studies were carried out using constant heating and isothermal gravimetric experiments up to 1000C. The microstructural changes, and nature of the oxides were analyzed using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. In the most extreme case a stable protective oxide layer, which otherwise didn’t exist in the binary case at any temperature, was maintained to above 700C.