scholarly journals Performance Comparison Between Isothermal Hot Corrosion And In Situ Cyclic Hot Corrosion of Nickel-Based Superalloys

2021 ◽  
Author(s):  
Adnan. U. Syed ◽  
Fabian Duarte Martinez ◽  
Tracey Roberts ◽  
Adriana Encinas-Oropesa ◽  
Nicolau I. Morar ◽  
...  
Keyword(s):  
Single Crystal ◽  
Hot Corrosion ◽  
Corrosion Damage ◽  
Performance Comparison ◽  
Type I ◽  
Type Ii ◽  
Dimensional Metrology ◽  
Corrosion Tests ◽  
Single Crystal Alloy ◽  
Test Conditions

AbstractAlthough a lot of work has been done to understand both major mechanisms of hot corrosion, namely type I (high-temperature hot corrosion) and type II (low temperature hot corrosion), there is very little information available on more representative cyclic performance in these regimes. This work addresses this by assessing the performance of isothermal (type I and type II) hot corrosion tests against combined (short and long) cyclic corrosion tests. Single-crystal alloy PWA 1484 and directionally solidified alloy MAR-M247 were assessed in all test regimes. Pre- and post-exposure dimensional metrology was used to quantify the corrosion damage and characterised using SEM/EDX. This paper highlights that the results of short cycle test conditions are more damaging compared to long cycle and standard isothermal type I and II test conditions. The cast nickel-based alloy MAR-M247 was found to be a better performer compared to PWA 1484 single-crystal alloy.

Modelling the Development of Type I Hot Corrosion on Coated and Uncoated Single Crystal Superalloys

2008 ◽  
Vol 595-598 ◽  
pp. 689-698
Author(s):  
N.J. Simms ◽  
A. Encinas-Oropesa ◽  
John R. Nicholls
Keyword(s):  
Single Crystal ◽  
Hot Corrosion ◽  
Gas Turbines ◽  
Laboratory Tests ◽  
Turbine Blades ◽  
Combined Cycle ◽  
Deposition Flux ◽  
Type I ◽  
Dimensional Metrology ◽  
Exposure Conditions

Gas turbines are critical components in the combined cycle power systems being developed to generate electricity from solid fuels, such as coal and biomass. The use of such fuels to produce fuel gases introduces the potential for significant corrosive and erosive damage to gas turbine blades and vanes. Single crystal superalloys have been developed for use with clean fuels but are now being deployed in industrial gas turbines. The performance of these materials, with coatings, has to be determined before they can be used with confidence in dirtier fuel environments. This paper reports results from a series of laboratory tests carried out using the ‘deposit replenishment’ technique to investigate the sensitivity of candidate materials to exposure conditions anticipated to cause type I hot corrosion in such gas turbines. The materials investigated have included the single crystal nickel-based superalloys CMSX-4 and SC2-B, both bare and with Pt-Al coatings. The exposure conditions within the laboratory tests have covered ranges of SOx (50 and 500 volume parts per million, vpm) and HCl (0 and 500 vpm) in air, as well as 4/1 (Na/K)2SO4 deposits, with deposition fluxes of 1.5, 5 and 15 5g/cm2/h, for periods of up to 500 hours at 900°C. Data on the performance of materials has been obtained using dimensional metrology: pre-exposure contact measurements and post-exposure measurements of features on polished cross-sections. These measurement methods allow distributions of damage data to be determined for use in the development of materials performance modelling. In addition, the types of damage observed have been characterised using standard optical and SEM/EDX techniques. The damage rates of the single crystal materials without coatings are too high for them to be used with confidence in gas turbines fired with gases derived from ‘dirty fuels’. Under the more severe combinations of gas composition, deposition flux and metal temperature, the corrosion rates of these materials with Pt-Al coatings are also excessive. The data produced from these tests has allowed the sensitivity of hot corrosion damage to changes in the exposure environment to be determined for the single crystal alloys and coating systems examined.

Isothermal high temperature low cycle fatigue behavior of Nimonic-263: Influence of type I and type II hot corrosion

2015 ◽  
Vol 622 ◽  
pp. 131-138 ◽  
Author(s):  
J.K. Sahu ◽  
B. Ravi Kumar ◽  
S.K. Das ◽  
N. Paulose ◽  
S.L. Mannan
Keyword(s):  
High Temperature ◽  
Hot Corrosion ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Type I ◽  
Type Ii ◽  
Cycle Fatigue ◽  
Type Ii Hot Corrosion

Evaluation of Alternate High Temperature Coatings to Improve Hot Corrosion Resistance in a Shipboard Environment

2009 ◽  
Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Corrosion Fatigue ◽  
Hot Corrosion ◽  
Turbine Engines ◽  
Type I ◽  
Gas Turbine Engines ◽  
Type Ii ◽  
Turbine Engine ◽  
Type Ii Hot Corrosion

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the turbine area (more specifically the first row turbine hardware) due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuel. The Navy’s technical community recognizes that engine corrosion problems are complex in nature and are often tied to the design of the overall system. For this reason, two working groups were formed. One group focuses on the overall ship system design and operation, including the inlet and fuel systems. The second, the corrosion issues working group, will review the design and performance of the turbine itself and develop sound, practical, economical, and executable changes to engine design that will make it more robust and durable in the shipboard operating environment. Metallographic examination of unfailed blades removed from a marine gas turbine engine with 18000 operating hours showed that the coating thickness under the platform and in the curved area of transition between the platform to the blade stem was either very thin, or in a few cases, non-existent on each unfailed blade. Type II hot corrosion was evident at these locations under the platform. It was also observed that this corrosion under the platform led to corrosion fatigue cracking of first stage turbine blades due to poor coating quality (high porosity and variable thickness). Corrosion fatigue cracks initiated at several hot corrosion sites and had advanced through the stems to varying degrees. Cracking in a few blades had advanced to the point that would have led to premature blade failure. Low velocity, atmospheric-pressure burner-rig (LVBR) tests were conducted for 1000 hours to evaluate several alternative high-temperature coatings in both Type I and Type II hot corrosion environments. The objectives of this paper are to: (1) report the results of the hot corrosion performance of alternative high temperature coating systems for under the platform of the 1st stage blade of 501-K34 gas turbine engine, (2) compare the performance of these alternative coating systems to the current baseline 1st stage blade coating, and (3) down select the best performing coating systems (in terms of their LVBR hot corrosion and thermal cycling resistance) to implement on future 501-K34 first stage blades for the Fleet.

scholarly journals Low Temperature Hot Corrosion Screening of Single Crystal Superalloys

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2098
Author(s):  
James Smialek ◽  
Simon Gray
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Aggressive Behavior ◽  
Cross Sections ◽  
Hot Corrosion ◽  
Micro Channel ◽  
Type Ii ◽  
Weight Changes ◽  
Chemical Differentiation

Single crystal superalloys were screened in Type II molten (Na,K)-sulfate hot corrosion re-coat tests in air +300 ppm SO2 at 700 °C. They exhibited large 20–40 mg/cm2 weight changes, repeated spallation, and non-protective, 25–50 μm thick corrosion layers after 300 h of testing. Scale cross sections revealed dual outer Ni(Co)O and inner Al(Cr)S-rich corrosion layers. This chemical differentiation was partially consistent with previous models of oxide fluxing, alloy sulfidation, NiO micro-channel diffusion, and synergistic dissolution mechanisms. Broad shallow pits or uniform attack morphologies were consistent with prior studies performed in high >100 ppm pSO2 environments. Higher Mo experimental alloys trended toward more degradation, producing 100 μm thick scales with distinct Al(Cr)S-rich inner layers or 500 μm thick NiO. The aggressive behavior in these environments supports the need for LTHC-resistant coatings for single crystal superalloys.

Performance Evaluation of High Temperature Coatings for Hot Section Turbine Components

2005 ◽  
Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Hot Corrosion ◽  
Gas Turbine Engine ◽  
Turbine Engines ◽  
Type I ◽  
Gas Turbine Engines ◽  
Type Ii ◽  
Power Sources ◽  
Turbine Engine

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class ships. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the hot section turbine area due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuels. Previous metallographic examination of several unfailed blades removed from a marine gas turbine engine after 18000 operating hours showed that the coating thickness under the platform and in the curved area of transition between the platform to the blade stem was either very thin, porous, and in a few cases, non-existent on each unfailed blade. Type II hot corrosion was evident at these locations under the platform. Corrosion fatigue cracks initiated at several hot corrosion sites and had advanced through the blade stems to varying degrees. Cracking in a few blades had advanced to the point that blade failure was imminent. The objectives of this paper are to: (1) report the hot corrosion results of alternative high temperature coating systems on Alloy M247 and Alloy 792 for hot section components of the 501-K34 gas turbine engine using a low velocity, atmospheric-pressure burner-rig (LVBR), (2) compare and rank hot corrosion performance of these coatings systems to the baseline coating/substrate system (2) down select the best performing coating systems (in terms of LVBR hot corrosion and thermal cycling resistance) to implement on future hot section components in the 501-K34 engine for the Fleet.

scholarly journals Corrosion Damage Mechanism of TiN/ZrN Nanoscale Multilayer Anti-Erosion Coating

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 400 ◽  
Author(s):  
Mingrui Geng ◽  
Guangyu He ◽  
Zhiping Sun ◽  
Jiao Chen ◽  
Zhufang Yang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Hot Corrosion ◽  
Salt Spray ◽  
Corrosion Damage ◽  
Damage Mechanism ◽  
Element Distribution ◽  
Salt Spray Corrosion ◽  
Corrosion Tests ◽  
Engine Compressor ◽  
Aero Engines

TiN/ZrN multilayers can effectively improve the erosion resistance of metals, particularly titanium alloys employed in aero engines. To explore the corrosion damage mechanism of TiN/ZrN nanoscale multilayers (nanolaminate), a novel [TiN/ZrN]100 nanolaminate coating was deposited on Ti-6Al-4V alloys by multi-arc ion plating method. Salt spray corrosion tests and hot corrosion experiment were carried out to evaluate the corrosion resistance of the coating. The corrosion and damage mechanisms were explored with the help of detailed microstructure, phase composition and element distribution characterizations. The salt spray corrosion tests showed that the [TiN/ZrN]100 nanolaminate coating possessed good corrosion resistance, which protected substrate against the corrosion. The low temperature hot corrosion tests showed that the oxidation occurred on the surface of the coating, which improved the oxidation resistance of the sample. However, the oxidized droplets squeezed the coating, and destroyed the oxidized layers. As a result, the coating was peeled off from the substrate. The research highlights the corrosion resistance of the novel TiN/ZrN nanolaminate coating and offers a support for their application in engine compressor blade.

Evaluation of Alternative High Temperature Coatings to Improve Hot Corrosion Resistance in a Shipboard Environment

2003 ◽  
Author(s):  
David A. Shifler ◽  
Dennis M. Russom ◽  
Bruce E. Rodman
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Hot Corrosion ◽  
Turbine Engines ◽  
Type I ◽  
Gas Turbine Engines ◽  
Type Ii ◽  
Low Velocity ◽  
Power Sources ◽  
Turbine Engine

501-K34 marine gas turbine engines serve as auxiliary power sources for the U.S. Navy’s DDG-51 Class. It is desired that 501-K34 marine gas turbine engines have a mean time between removal of 20K hours. While some engines have approached this goal, others have fallen significantly short. A primary reason for this shortfall is hot corrosion (Type I and Type II) damage in the turbine area (more specifically the first row turbine hardware) due to both intrusion of salts from the marine air and from sulfur in the gas turbine combustion fuels. In order to improve the durability of hot section components with more corrosion resistant coatings, low velocity, atmospheric-pressure burner-rig (LVBR) tests were conducted for up to 2000 hours to evaluate several alternative high-temperature coatings in both Type I and Type II hot corrosion environments. The objectives of this paper are to report the results of: (1) the hot corrosion performance of these alternative high temperature coating systems for the 1st stage vane of a given gas turbine engine; (2) compare the performance of these alternative coating systems to the current, baseline 1st stage vane coating and (3) downselect the best performing coating systems (in terms of their LVBR hot corrosion and thermal cycling resistance) to install as rainbow arrays into the first stage vanes of several engines for Fleet evaluation.

Corrosion Properties of Inconel Alloy 600 Coated by Simultaneous Aluminizing-Chromizing Process

2007 ◽  
Vol 546-549 ◽  
pp. 1763-1768
Author(s):  
Ahmed Moosa ◽  
Jalil Karim Ahmed ◽  
Ali Hoobi
Keyword(s):  
Hot Corrosion ◽  
Aluminide Coating ◽  
Diffusion Coating ◽  
Single Step ◽  
Corrosion Tests ◽  
Rate Law ◽  
Inconel 600 ◽  
Test Conditions ◽  
Parabolic Rate ◽  
Inconel 600 Alloy

In this work Inconel 600 alloy was coated with two different types of coatings, Crmodified aluminide coating and Y- doped chromium modified aluminide coating . Diffusion coating was carried at 1050 oC for 8 hrs under Ar atmosphere by single step aluminizing- chromizing process and by single step aluminizing- chromizing- yttriumizing process. The cyclic hot corrosion tests of IN 600 and its coated systems deposited with 2 mg / cm2 NaCl / Na2SO4 (100/0, 50/50, and 0/100 wt. %) deposits were conducted at 900 oC in air for 105 hrs at 15 hrs cycle. The hot corrosion kinetic of uncoated Inconel 600 alloy follows parabolic rate law when oxidized with 100% Na2SO4 deposits, whereas it follows a linear rate law when oxidized with 100% NaCl deposits and with (50% NaCl + 50% Na2SO4) deposits. In cyclic hot corrosion tests, the parabolic rate constant (kP) values for Cr- modified aluminide coating when oxidized with NaCl / Na2SO4 concentrations (100/0, 50/50, and 0/100 wt. %) deposits are: 2.67x10-6, 2.73x10-6, and 8.34x10-7 (mg2/cm4)/s. respectively. But for Y- doped chromium modified aluminide coating are: 2.10x10-6, 1.51x10-6, and 6.66x10-7 (mg2/cm4)/s. respectively, under the same test conditions. The kP values for both coated systems oxidized with 100% Na2SO4 deposits are one order of magnitude lower than that for 100% NaCl, and for (50% NaCl + 50% Na2SO4) deposits under the same test conditions.

Interaction of Ta and Cr on Type-I hot corrosion resistance of single crystal Ni-base superalloys

2017 ◽  
Vol 117 ◽  
pp. 35-42 ◽  
Author(s):  
J.X. Chang ◽  
D. Wang ◽  
G. Zhang ◽  
L.H. Lou ◽  
J. Zhang
Keyword(s):  
Corrosion Resistance ◽  
Single Crystal ◽  
Hot Corrosion ◽  
Type I
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