Evaluation of Type I Hot Corrosion of Marinized Materials Through Low Velocity Burner Rig Testing
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Abstract:
This talk will focus on the materials used in gas turbine engines which have a wide variety of applications, from powering the vast majority of commercial and military aircrafts as well as military naval fleets to their use in power generation plants. Current technology takes advantage of the high temperature strength and toughness of nickel-based superalloys, which are used for most components in the hot sections of turbine engines. In order to preserve the integrity of the engine and protect the nickel-based parts from harsh environments, as well as ever-rising operating temperatures, protective coatings have been put in place. Hot corrosion is a degradation mechanism characteristic of salty (marine) environments where the presence of salt and high temperatures prompts a process in which molten salt infiltrates metal coatings and causes a series of reactions that result in material loss, sulfidation, deep penetration of salt constituents into the metal, and ultimately mechanical failure
Current protective coatings offer some relief against hot corrosion, but the inevitable infiltration of salt through the coating and/or the substrate compromises the functionality of the engine. Continuous testing and evaluation of new materials is required due to the constant need for higher energy efficiency and therefore higher operating temperatures within turbines, which will only exacerbate the already existing degradation problems. Consequently, it is imperative to continue the advancement of hot corrosion prevention technology.
In this talk, I will describe efforts to assess the durability of new candidate materials for marine gas turbine systems using burner rig testing and quantitative assessment protocols we have developed. A new commercial substrate superalloy, representative of the materials used in the hot sections of marine gas turbines, is used to evaluate the effect that small additions of hafnium and silicon have on type I hot corrosion attack. The base substrate alloy as well as three iterations (base alloy with added hafnium, base alloy with added silicon, and base alloy with added hafnium and silicon) are evaluated in extended low velocity burner rig tests under type I hot corrosion conditions. After exposure, SEM and EDS are used to investigate the extent of corrosion, morphology of attack, and useful material left, to determine the effects hafnium and silicon have on the type I hot corrosion. Results show differences in the extent and nature of attack between the different alloy iterations, with additions of both hafnium and silicon enhancing the performance of the alloy under type I conditions the most. It is believed that the hafnium addition was detrimental to the alloy’s performance due to over doping. However, the addition of silicon can curve the activity of hafnium to a level that is beneficial to the overall performance of the alloy.
This talk will focus on the materials used in gas turbine engines which have a wide variety of applications, from powering the vast majority of commercial and military aircrafts as well as military naval fleets to their use in power generation plants. Current technology takes advantage of the high temperature strength and toughness of nickel-based superalloys, which are used for most components in the hot sections of turbine engines. In order to preserve the integrity of the engine and protect the nickel-based parts from harsh environments, as well as ever-rising operating temperatures, protective coatings have been put in place. Hot corrosion is a degradation mechanism characteristic of salty (marine) environments where the presence of salt and high temperatures prompts a process in which molten salt infiltrates metal coatings and causes a series of reactions that result in material loss, sulfidation, deep penetration of salt constituents into the metal, and ultimately mechanical failure
Current protective coatings offer some relief against hot corrosion, but the inevitable infiltration of salt through the coating and/or the substrate compromises the functionality of the engine. Continuous testing and evaluation of new materials is required due to the constant need for higher energy efficiency and therefore higher operating temperatures within turbines, which will only exacerbate the already existing degradation problems. Consequently, it is imperative to continue the advancement of hot corrosion prevention technology.
In this talk, I will describe efforts to assess the durability of new candidate materials for marine gas turbine systems using burner rig testing and quantitative assessment protocols we have developed. A new commercial substrate superalloy, representative of the materials used in the hot sections of marine gas turbines, is used to evaluate the effect that small additions of hafnium and silicon have on type I hot corrosion attack. The base substrate alloy as well as three iterations (base alloy with added hafnium, base alloy with added silicon, and base alloy with added hafnium and silicon) are evaluated in extended low velocity burner rig tests under type I hot corrosion conditions. After exposure, SEM and EDS are used to investigate the extent of corrosion, morphology of attack, and useful material left, to determine the effects hafnium and silicon have on the type I hot corrosion. Results show differences in the extent and nature of attack between the different alloy iterations, with additions of both hafnium and silicon enhancing the performance of the alloy under type I conditions the most. It is believed that the hafnium addition was detrimental to the alloy’s performance due to over doping. However, the addition of silicon can curve the activity of hafnium to a level that is beneficial to the overall performance of the alloy.
Biography:
Kliah N. Soto Leytan is a doctoral candidate in the materials science and engineering department at the University of California, Irvine (UCI) working under the supervision of Dr. Daniel R. Mumm. She received her university diploma in physics and mathematics in 2012 from Occidental College in Los Angeles, California. She completed her master’s degree in 2014 at UCI and is expected to obtain her doctorate in June of this year. In 2015 Kliah was a recipient of the Schlumberger foundation faculty for the future grant. Kliah’s research focuses on developing testing protocols and characterizing the degradation of high temperature turbine materials.
Kliah N. Soto Leytan is a doctoral candidate in the materials science and engineering department at the University of California, Irvine (UCI) working under the supervision of Dr. Daniel R. Mumm. She received her university diploma in physics and mathematics in 2012 from Occidental College in Los Angeles, California. She completed her master’s degree in 2014 at UCI and is expected to obtain her doctorate in June of this year. In 2015 Kliah was a recipient of the Schlumberger foundation faculty for the future grant. Kliah’s research focuses on developing testing protocols and characterizing the degradation of high temperature turbine materials.
