Skip to main content
Article thumbnail
Location of Repository

Degradation of Environmental Protection Coatings for Gas Turbine Materials

By Laura Nalin

Abstract

Nowadays, problems of component materials reliability in gas and oil-fired gas turbines focus on assessing the potential behaviour of commonly employed coatings, in order to avoid expensive and unpredictable failure in service and producing new materials whose performance meets life time and manufacturing/ repairing requirements. This MPhil project has investigated the oxidative and corrosive degradation mechanisms for some of the alloy/coatings systems (CMSX-4, CMSX-4/ RT22, CMSX-4/ CN91 and CMSX-4/ “LCO22”), which are currently used for turbines blades and vanes, in order to achieve a better knowledge of materials behaviour and to improve models for the prediction of turbine components’ lives. To achieve this target the study has made use of realistic simulations of turbine exposure conditions in combined with pre- and post-exposure metrology of bar shape materials samples, while optical microscopy has been applied to describe the microstructural evolution during the exposure and the products of the degradation for the hot corrosion. For high temperature oxidation, over extended periods of time (up to 10,000 hours), the research has allowed to describe the morphological changes in respect of the exposure time and temperature and to determine the oxidation kinetics experienced by the alloy and coatings. A model has been presented for predicting θ- α-Al2O3 growth. Moreover, using NASA COSP spalling model, with rate constants values coming from this study, a comparison between experimental mass change data and prediction has been shown. The hot corrosion study has provided new quantitative metal loss data and observations that extend/validate an existing model for materials life prediction, based on defining the severity of the corrosion conditions through measures of gas composition and contaminant deposition flux

Publisher: Cranfield University
Year: 2008
OAI identifier: oai:dspace.lib.cranfield.ac.uk:1826/4522
Provided by: Cranfield CERES

Suggested articles

Citations

  1. (2001). A comparative study of two inward grown Pt modified Al diffusion coatings on a single crystal Ni base superalloy. doi
  2. (2003). A deterministic interfacial cyclic oxidation spalling model. doi
  3. (1991). A practical guide to high-temperature alloys. doi
  4. (2006). Advanced burner-rig test for oxidation-corrosion of MCrAlY/superalloys systems. doi
  5. Advanced Technological Materials. doi
  6. (2004). ALLBATROS advanced long life blade turbine coating systems. doi
  7. (1990). Alumina scale growth at zirconia/MCrAlY interface: a microstructural study. Microscopy of oxidation. doi
  8. (2002). Aluminide diffusion coatings for Ni based superalloys doi
  9. (1997). An assessment of thermal spray coating technologies for high temperature corrosion protection. Materials Science Forum Vols doi
  10. (2003). Application of a Simple Statistical Spalling Model for the Analysis of High Temperature, Cyclic-Oxidation Kinetics Data. Oxidation of Metals, doi
  11. (1993). Applications of coatings in coal-fired energy systems. doi
  12. Centre d’information du cobalt. doi
  13. (1999). Characterization of thermally cycled alumina scales. Microscopy of oxidation. doi
  14. (2005). Coating for gas turbine materials and long term stability issues. doi
  15. (1986). Coating service experience with industrial gas turbine. doi
  16. Coatings for high temperature applications. CEC High Temperature Materials Information Centre, Petten, The Netherlands.1983.
  17. (1987). Cobalt-based Superalloys for Applications in Gas Turbines. doi
  18. (2008). Comparative study on oxidation behaviour of selected MCrAlY coating by elemental concentration profile analysis. doi
  19. (2002). Comparison of inward and outward grown Pt modified aluminide diffusion coatings on a Ni base single crystal superalloy. doi
  20. (1996). Concept of Functionally Graded Materials for Advanced Thermal Barrier Coating Application. doi
  21. (2000). Corrosion and Environmental Degradation. Vol I.
  22. (2001). Corrosion and Lifetime Modelling of Components in Coal fired Combined Cycle Power Systems. Lifetime Modelling of High Temperature193 Corrosion Processes, doi
  23. Cyclic Oxidation Testing and Modelling:a NASA Lewis Prospective. Cyclic Oxidation of High Temperature Materials. doi
  24. (2000). Development and application of a methodology for the measurement of corrosion and erosion damage in laboratory, burner rig and plant environment. doi
  25. (1996). Development of alloyed and dispersion-strengthened MCrAlY coating. doi
  26. (2007). Development of internal cavities in platinum-aluminide coatings during cyclic oxidation. doi
  27. (2001). Development of Type II hot corrosion in solid fuel fired gas turbines. Lifetime Modelling of High Temperature Corrosion Processes,
  28. (2000). Directed Vapor Deposition of Thermal Barrier Coating”. doi
  29. (2005). Doctorial Thesis. Study of hot corrosion of single crystal superalloy and platinum-aluminide coatings.
  30. (2000). Effect of composition on the oxidation and hot corrosion resistance of NiAl doped with precious metals. doi
  31. (2006). Effect of Pt and Al content on the long-term, high temperature oxidation behaviour and interdiffusion of a Pt-modified aluminide coating deposited on Ni-base superalloys. Surface and Coating technology 201, doi
  32. (2004). Effects of surface oxidation during HVOF processing on the primary stage oxidation of a CoNiCrAlY coating. doi
  33. (2007). Energy Information Administration, doi
  34. (2003). Energy Systems and Sustainability. Power for a Sustainable Future. doi
  35. (2002). Environmental degradation issues in gas turbines and their relevance to plant life extantion-R&D initiatives. Enviromental degradation in gas turbine,
  36. (1995). Erosioncorrosion modelling of gas turbine materials for coal-fired combined cycle power generation, doi
  37. (2004). Failure of first gas turbine blades. doi
  38. (1973). for the hot corrosion of nickelbase alloys. doi
  39. (2006). Fundamentals and Application. doi
  40. (2008). H.K.D.H..Rafting in Nickel Based Supetalloys. http://www.msm.cam.ac.uk
  41. (1995). Heat and Power. A practical Guide to the Evaluation, development, Implementation and Operation of Cogeneration Schemes. Energy Pubblication. doi
  42. (1978). High temperature alloys for gas turbine. Applied science doi
  43. (1982). High Temperature Alloys for Gas Turbines doi
  44. (1986). High temperature alloys for gas turbines and other applications doi
  45. (2004). High temperature corrosion in gas turbine: Thermodynamic modelling and experimental results. PhD Thesis.
  46. (2002). High Temperature Corrosion Issues in Energy-Related Systems.
  47. (1990). High temperature corrosion of engineering alloy. doi
  48. (1988). High temperature corrosion. Per Kofstad, doi
  49. High temperature materials corrosion in coal gasification atmospheres. CEC High temperature Materials Information Centre, Petten (N.H.), The Netherlands.
  50. (1987). High temperature materials for aerospace and industrial doi
  51. (2006). High temperature oxidation of metals. doi
  52. (1989). High-Temperature corrosion of aluminia-forming coatings for superalloy. doi
  53. (1997). Hot corrosion and its prevention in high temperature heavy oil firing turbines. Materials Science Forum Vols. doi
  54. (2006). Hot corrosion and oxidation behaviour of a novel Pt-Hf-modified y’-Ni3Al+y-Ni-based coating. doi
  55. (2006). Hot corrosion and performance of nickelbased coatings. doi
  56. (1979). Hot Corrosion Degradation of Metals. A Unified Theory . Final Scientific Report.
  57. (2002). Hot corrosion in gas turbine components. doi
  58. (2002). Hot corrosion of materials: a Fluxing mechanism? doi
  59. (1969). Hot Corrosion. doi
  60. (2005). Identification of hot corrosion resistant MCrALY based bond coating for gas turbine engine application. doi
  61. (2006). Influence of the thermal-spray procedure on the properties of a CoNiCrAlY coating. doi
  62. (1999). Life prediction for hot gas path materials in coal-fired gas turbines. Project Summary 259,
  63. (1997). Mathematical modelling of alloy oxidation. doi
  64. (1997). Measurement of Corrosion Damage in Coal-fired Combined Cycle Power Systems’, doi
  65. (2003). Measurements and compilation of materials degradation data in the COST522 programme. Life Cycle Issues in Advance Energy Systems, doi
  66. (1980). Mechanism of Na2SO4 Induced Corrosion at 600°-900°C. doi
  67. (2002). Metallic interconnections for solid oxide fuel cell-a review. Life Cycle Issues in Advanced Energy Systems. doi
  68. (1999). Microscopy of oxidation.
  69. (1990). Microscopy of the corrosion of high temperature coatings. Microscopy of Oxidation.
  70. (2004). Microstructural and microchemical development of simple and Pt-modified aluminide diffusion coatings during long term oxidation at doi
  71. (1999). Microstructural study of the theta-alpha transformation in alumina scales formed on nickel-aluminides. Microscopy of oxidation. doi
  72. (2004). Microstructure of oxide scales on aluminide diffusion coatings after short time oxidation at 1050°C. doi
  73. (1982). Microstructure, adhesion and growth kinetics of protective scales on metals and alloys. doi
  74. (2007). MSc in Advance Materials. Surface Science and Engineering.
  75. (1970). Na2SO4-induced accelerated oxidation (hot corrosion) of nickel. doi
  76. (2007). Numerical simulation of cyclic oxidation kinetics with automatic fitting of experimental data. doi
  77. (2007). of heat exposure time on isothermal degradation of plasma sprayed CoNiCrAlY coatings. doi
  78. (1997). Oxidation of aluminides. doi
  79. (2005). Oxidation of high-temperature coatings.
  80. (2003). Oxidation of simple and Pt-modified aluminide diffusion coatings on Ni-base superalloys-I. Oxide scale microstructure.
  81. (2003). Oxidation of simple and Pt-modified aluminide diffusion coatings on Ni-base superalloys-II. Oxide scale feilure.
  82. (1978). Oxide morphology and spalling model for NiAl. doi
  83. (2006). Parameters affecting TGO growth and adherence on MCrAlY-bond coats for TBC’s. doi
  84. (1992). Power Plants. Including Combined cycle Gas Turbine (CCGT) Plants. doi
  85. (1991). Principles of energy conversion.
  86. (1997). Protective Oxide Scale and their
  87. second and third generation of single-crystal Ni-base superalloy.
  88. (2003). Secretary of State for Trade and Industry by Command of Her Majesty;
  89. (1999). SEM and TEM studies of PtAl diffusion coatings under isothermal oxidation. Microscopy of oxidation. doi
  90. (2002). Smart overlay coatings-concept and practice. doi
  91. (1997). Some Practical Aspects of Corrosion and Coatings in Utility Gas Turbines. Materials Science Forum Vols. doi
  92. (1997). Spallation of Oxide Scales from NiCrAlY Overlay Coatings. Materials Science Forum Vols. doi
  93. (1997). Standard free energy change of formation per unit volume: a new parameter for evaluating nucleation and growth of oxides, sulphides, carbides and nitrides. doi
  94. (1989). State of the art on high-temperature corrosion-resistant coatings. doi
  95. (2001). strength of Ni-base superalloy coatings. doi
  96. (1981). Structure and properties of engineering alloys.
  97. (1999). Studies on the transient stage of oxidation doi
  98. (1989). Sub-melting Point Hot Corrosion of Alloys and Coatings. doi
  99. (2007). Substrate Effect on the High Temperature Oxidation Behaviour of a Pt-modified Aluminide Coating. Part II: Long-term Cyclic-oxidation Tests at 1050°C. doi
  100. (2006). Substrate effect on the high-temperature oxidation behaviour of a Pt-modified aluminide coating. Part I: influence of the initial chemical composition of the coating surface. doi
  101. (2002). Superalloys. A technical Guide. Second Edition. doi
  102. (2000). Surface rumpling of a (Ni, Pt) Al Bond Coat induced by cyclic oxidation. doi
  103. Sustainable power generation and supply. Powering the future. EPSRC Secretary of State for Trade and Industry by Command of Her Majesty.
  104. (1983). The analysis of oxidation and hot corrosion data-a statistical approach.
  105. (2006). The growth and influence of thermally grown oxide in a thermal barrier coating. doi
  106. (1999). The influence of NiAl3on the high temperature oxidation of a plasma-sprayed overlay coating. doi
  107. (1997). The oxidation and corrosive degradation of vacuum plasma spayed coatings in industrial gas turbine environmental. Materials Science Forum Vols 251-254, doi
  108. (1992). The oxidation behaviour of Ni-Al-I. Phase transformations in the alumina scale during oxidation of Ni-Al and Ni-Al-Cr alloys. doi
  109. (1997). The oxidation of Alumina-Forming Alloys. Materials Science Forum Vols. doi
  110. (2003). Thermal Power Plant. Simulation and Control. Damian Flynn. doi
  111. (1997). Thermocycling behaviour of microstructurally modified EB-PVD thermal barrier coatings. Materials Science Forum Vols doi
  112. (2005). Transient alumina transformation on a sputtered K38G nanocrystal coating. doi
  113. (2004). Universal characteristics of an interfacial spalling cyclic oxidation model. doi
  114. (2005). α-NiPt(Al) and phase equilibria in the Ni-Al-Pt system at 1150°C. doi

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.