Materials practical application in industry with and without coatings
Without oxidation protective layer of MCrAlY alloys oxidize these superalloys at the temperature higher 800°C. Best of NiCoCrReAlY alloys protect the nickel superalloys from oxidation up to 950°C.
The following book is a guide for superalloys: Superalloys: A Technical Guide, 2nd Edition, Matthew J. Donachie, Stephen J. Donachie - 2002 - (pp 439)
This book covers virtually all technical aspects related to the selection, processing, use, and analysis of superalloys. The text of this new second edition has been completely revised and expanded with many new figures and tables added. In developing this new edition, the focus has been on providing comprehensive and practical coverage of superalloys technology. Some highlights include the most complete and up-to-date presentation available on alloy melting. Coverage of alloy selection provides many tips and guidelines that the reader can use in identifying an appropriate alloy for a specific application. The relation of properties and microstructure is covered in more detail than in previous books.
I hope you will get benefit from it.
Yes dear
You asked for actual service temperatures with and without coatings. Now these materials practically in service subjected to environmentally induced degradation of two types – hot corrosion and high temperature oxidation. Hot corrosion is generally associated with alkali metal and sulfur reaction to form molten sulfates which cause rapid attack. High temperature hot corrosion occurring in the temperature range 850-950C and low temperature hot corrosion taking place in the range 593-760C. Now with no presence of alkali metal contaminants and sulfur in the environment, high temperature oxidation dominates. Higher the temperature, more rapid is the oxidation. In this case the limit in general 1000-1150C for these alloys
Now coating does actually not only increase the service temperature but also increase the service life-time as the function of the coating is form very protective and adherent layers, thus protecting the underlying base material from oxidation, corrosion attack and degradation. In my opinion the maximum operating temperature which guaranteed long term stability of the coating layer is considered as actual service temperatures which in most cases 50-100C higher than uncoated case.
Thank you
Best of NiCoCrReAlY alloys protect the nickel superalloys from oxidation up to 950°C.
Рабочие температуры данных сплавов будут определяться системой
их легированности и температурной областью растворения упрочняюшей фазы.
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