High Temperature Oxidation of Metals and Ceramics: Corrosion
Sponsored by: TMS Corrosion and Environmental Effects Committee
Program Organizers: Kenneth Kane, Oak Ridge National Laboratory; Elizabeth Sooby, University Of Texas At San Antonio; Patrick Brennan, General Electric Research; Lavina Backman, U.S. Naval Research Laboratory; Kinga Unocic, Oak Ridge National Laboratory; Richard Oleksak, National Energy Technology Laboratory; David Shifler, Office of Naval Research; Raul Rebak, GE Global Research
Monday 2:00 PM
October 10, 2022
Room: 335
Location: David L. Lawrence Convention Center
Session Chair: Patrick Brennan, General Electric; Raul Rebak, General Electric
2:00 PM Invited
Factors Affecting Deposit-Induced Corrosion of Aero-Turbine Components at Elevated Temperatures: Brian Gleeson1; 1University of Pittsburgh
Hot corrosion is an accelerated degradation process that is generally considered to involve deposition of corrosive species (e.g., sulfates) from the surrounding environment to the surface of hot components, followed by destruction of the protective oxide scale. Gas turbine engine components, particularly high-pressure turbine blades and rotors, exposed to harsh environments are apt to encounter two modes of hot corrosion: high temperature hot corrosion (Type I) in the temperature range 850-1000°C and low temperature hot corrosion (Type II) in the range 600-800°C. This presentation will overview research conducted at the University of Pittsburgh to advance understanding of sulfate-based deposit-induced corrosion. It will be shown that an effective laboratory-scale testing procedure has been developed that better simulates the form and extent of degradation found in service.
2:30 PM
Advanced Characterization of Hot Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning-assisted 3D X-ray Microscopy to Reveal High Temperature Fracture and Crack Arrest Mechanisms: Andy Holwell1; Maadhav Kothari1; Hrishikesh Bale1; Simon Gray2; Jonathan Leggett3; 1Carl Zeiss Microscopy Llc; 2Cranfield University; 3Rolls Royce
Single crystal nickel superalloys are typically used in power generation and aviation due to their unique properties. Recently, incidents of failure at increased temperature has caused Type II hot corrosion leading to cracking in blade roots, resulting in catastrophic failure. Understanding failure mechanism and crack characterization is critical. After exposing a salted C-ring specimen to 500°C air for 92 hours, we demonstrate a novel X-ray microscopy workflow using deep learning-based algorithms for data reconstruction and segmentation, combined with scanning electron microscopy in order to study cracks, crack tips and crack arrest points developed during stress corrosion cracking and their relation to the crystalline microstructure.By extracting the fracture tip, both crystal plasticity and crystal deformity can be studied in detail resulting in orientation tomography of the corroded region. Using this correlative workflow we are able to identify structural defects and fracture mechanisms previously not visible from traditional CT.
2:50 PM
Obtaining Surface Coatings Providing Protection Against High Temperatures in the Production of Coke: Borys Sereda1; Iryna Kruhliak1; Dmytro Sereda1; Aleksandr Gaydaenko1; 1Dneprovsky State Technical University
In order to improve the reliability of internal combustion engines of freight transport and increase their service life, the technology of surface treatment using the SHS-method has been applied. For hardening the parts of the gas distribution mechanism of trucks, a gas transmission technology was used to produce titanium coatings alloyed with chromium. The optimal compositions of SHS-mixtures for obtaining titanium-chromium coatings were developed, the influence of the compositions of SHS-mixture on the properties of the obtained coatings was determined. For the purpose of analyzing the process of forming complex doped coatings based on titanium under SHS conditions, the equilibrium state of the reaction products in multicomponent powder systems was calculated. The research results indicate an increase in the wear resistance of the mechanisms of internal combustion engines after surface treatment of 1.8-2.1 times, which is correlated with an increase in the microhardness of the surface layer.
3:10 PM
Effects of Secondary Additions to Na2SO4 Deposits on High-Temperature Hot Corrosion: Preston Nguyen1; Brian Gleeson1; 1University of Pittsburgh
Ni-based superalloys are crucial in the operation of gas turbine engines. Due to the interaction of environmental deposits and gases during high temperature operation, hot corrosion testing is needed to elucidate the effects of deposit, atmosphere, and temperature on the degradation of Ni-based superalloys. The principal aim of this study was to investigate the corrosive effects of commonly found environmental species when added to Na2SO4. Both NaCl-Na2SO4 and SiO2-Na2SO4 salt mixtures were studied initially to evaluate the hot corrosion behavior and to elucidate the mechanisms that affect the reaction products that form during the exposures. Developing the understanding behind the hot corrosion behavior for these binary melts on Ni-based superalloys will help fulfill current knowledge gaps and enable better mitigation strategies.
3:30 PM
Environmentally Assisted Cracking of Nickel and Iron Based Alloys in Te-containing Molten Salts: Mohammad Umar Farooq Khan1; Miranda Mazza1; Lesley Frame2; Stephen Raiman1; 1Texas A&M University; 2University of Connecticut
To understand the problem of fission product cracking, the influence of grain boundary engineering (GBE) on Te diffusion across surface grain boundaries was investigated. The work focuses on testing the GBE methodology for improving corrosion resistance in Te-containing molten salt environment. The material used in the study is a nickel-based alloy IN617, a recently ASME nuclear code-approved nickel alloy. To maximize the low coincidence site lattice (CSL) boundaries, a matrix was devised for cold working percentage and heat treatment temperature and time. Various CSL boundaries were generated by applying cold working on IN617 alloy samples to different percentages (0, 15%, 37.5%). Sample were exposed to FLiNaK salt containing Te at 800 °C for up to 100 hours. The microstructural characterization of the samples will be presented using optical microscopy and scanning electron microscopy. techniques. The influence of grain boundary characteristics on the corrosion attack and elemental ingress will be discussed.
3:50 PM Break
4:10 PM
Understanding Mixed Sulfate-oxide Induced Hot Corrosion of Alumina-forming Alloys: David Poerschke1; Atharva Chikhalikar1; 1University of Minnesota
There is growing evidence that mixed cation, multi-anion (oxide-sulfate) deposits can accelerate alloy oxidation at temperatures well outside the temperature ranges of classical sulfate-induced hot corrosion. However, there is limited knowledge of the interplay between (i) alloy chemistry and associated minor thermally grown oxide (TGO) constituents, (ii) deposit chemistry, including the effect of changing cation ratio and sulfate content, and (iii) the gas atmosphere on the severity and nature of the hot corrosion process. This work systematically explored these factors to understand the features differentiating degradation caused by calcium sulfate from other deposit-induced degradation modes. Alloy coupons were oxidized in the presence of various deposit chemistries, and the samples were characterized using an automated image analysis approach to generate large datasets enabling quantitative differentiation of degradation modes. The insights emerging from the experiments can inform future alloy design strategies.
4:30 PM
Analysis and Simulation of Alkoxide Corrosion Occurring in Automotive Metals with Biofuels: Visheet Arya1; Rüdiger Reitz1; Matthias Oechsner1; Eugen Gazenbiller2; Daniel Höche2; 1MPA-IfW TU Darmstadt; 2Helmholtz-Zentrum Hereon
In fuel-bearing components at elevated working temperatures, component lifetimes highly depend on the susceptibility to alkoxide corrosion. This corrosive degradation is unique with its spontaneous character and tremendously high material degradation rates after initiation. Present work showcases a novel high pressure-temperature micro-reactor which is able to conduct measurements with high to assess exact corrosion initiation times and reaction rates. Preliminary experiments were conducted to analyze corrosion initiation times and temperature dependability on surface conditions through a phenomenological approach. In addition, several biogenic-fossil fuel blends, including field relevant impurities were also tested for their corrosivity. Experiments were conducted in the framework of DoE and were analyzed with methods such as anova and factor elimination. Furthermore, the corrosion kinetics were extracted from experimental data points to develop a microscale simulation model. First results are able to successfully replicate corrosion kinetics and pit morphologies.
4:50 PM
Materials Compatibility of Automotive Alloys in Synthetic Fuels - Test Method Development to Evaluate the Corrosion Behavior of Aluminum Materials in Oxygenates(OMEs): Rüdiger Reitz1; Visheet Arya1; Matthias Oechsner1; 1MPA-IfW TU Darmstadt
In the framework of a comprehensive DoE-based test approach, potential corrosion-stimulating fuel components such as water and chloride are varied in order to identify their respective impact on material compatibility. For example, the degree of corrosion documents a significant influence of the blend content between OME and fossil Diesel fuel, especially at an increased water content. In contrast, the influence of the salt concentration is rather moderate, although chloride is the actual electrochemical corrosion-stimulating component. To clarify this contradiction, addition electrochemical instrumented immersion tests were carried out in order to characterize pitting initiation behavior and its respective impact on passive layer resistance. Superimposed mechanical loads were applied by means of a servo hydraulic test facility. This method enables to investigate additional impact on crack initiation and possible hydrogen-induced effects. Finally, an evaluation matrix was used to identify critical fuel–material scenarios and classify suitable materials for industrial and automotive application.