Failure mechanism of MCrAlY coating at the coating‐substrate interface under type I hot corrosion

2019 ◽  
Vol 70 (9) ◽  
pp. 1593-1600 ◽  
Author(s):  
Pimin Zhang ◽  
Ru Lin Peng ◽  
Xin‐Hai Li
Keyword(s):  
Failure Mechanism ◽  
Hot Corrosion ◽  
Type I ◽  
Substrate Interface ◽  
Mcraly Coating

Hot corrosion failure mechanism of graphite materials in molten solar salt

2015 ◽  
Vol 132 ◽  
pp. 260-266 ◽  
Author(s):  
Yang-tao Xu ◽  
Tian-dong Xia ◽  
Wan-ping Wang ◽  
Gui-lan Zhang ◽  
Bao-lin Jia
Keyword(s):  
Failure Mechanism ◽  
Hot Corrosion ◽  
Corrosion Failure ◽  
Solar Salt

20612 Failure Mechanism by Hot Corrosion of Superheater Tube Alloy 625 in High-Efficiency Waste-to-Power Plant Boilers

2013 ◽  
Vol 2013.19 (0) ◽  
pp. 353-354
Author(s):  
Kazumasa TAKEMURA ◽  
Hiroyuki MORITA ◽  
Masayuki YOSHIBA ◽  
Masaru TAKAKURA
Keyword(s):  
Power Plant ◽  
Failure Mechanism ◽  
Hot Corrosion ◽  
High Efficiency ◽  
Alloy 625 ◽  
Superheater Tube

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 Repair Joints in Nickel-Based Superalloys With Improved Hot Corrosion Resistance

1993 ◽  
Author(s):  
K. A. Ellison ◽  
P. Lowden ◽  
J. Liburdi ◽  
D. H. Boone
Keyword(s):  
Hot Corrosion ◽  
Structural Changes ◽  
Base Alloy ◽  
Metallographic Analysis ◽  
Slight Reduction ◽  
Type I ◽  
Aluminide Coatings ◽  
Point Depressant ◽  
Identical Test ◽  
Nickel Base

Sample repair joints in the nickel-base superalloys Inconel IN-713 and IN-738 were tested in the laboratory for Type I high temperature hot corrosion (HTHC) resistance at 900°C. The joints were produced using a conventional “wide-gap” brazing process, having a composition similar to IN-718, and a novel powder metallurgy repair technique LPM™ which in this study had a composition similar to alloy IN-738. Metallographic analysis of the resulting structures showed that the IN-718 based repairs, with and without simple aluminide coatings, had suffered extensive intergranular attack of the braze joints. However, the HTHC resistance of cast IN-718 was found to be excellent under identical test conditions. A comparison of the uncoated LPM™ repair joints and cast IN-738 revealed only subtle differences in the morphology of the corrosion products; the maximum depths of attack were similar in each case. Silicon modified aluminide coatings provided a slight reduction in the rate of attack for the IN-738 alloy, while simple aluminide coatings were less resistant to HTHC than the base alloy. Similar results were found for the LPM™ joints, however localized coating penetration was observed in the vicinity of boride particles embedded in the coatings. These differences in behaviour were interpreted with reference to the chemical and structural changes brought about by the use of varying levels of boron as a melting point depressant in the repair layers.

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.

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