PRACTICAL IMPLICATIONS OF THE USE OF ALUMINIDE COATINGS FOR THE CORROSION PROTECTION OF SUPERALLOYS IN GAS TURBINES
Aluminide coatings have been in use for some considerable time as a means of protecting nickel and cobalt based superalloys from oxidation and hot corrosion attack in both aero- and industrial gas turbines. Their practical usage however has not been achieved without problems. In examining the overall role of coatings in achieving or prolonging component life, their advantages and disadvantages have to be considered most carefully, especially as the diversity of potential substrate alloys increases. The primary objective of this paper is therefore to consider in some detail the nature of the difficulties incurred in aluminide coating of superalloys, especially in terms of prolonging component life without prejudice to performance, integrity and safety of the engine. In considering this, the paper will first of all review the objectives and requirements of using aluminide coatings, the processes currently commercially available, the compatibility of aluminide coatings with various superalloys substrates as well as the more general question of overall quality control of both the coating and the coated component. The properties of coatings themselves will be considered in terms of their corrosion resistance, overall thermal and structural stability, and effect on the mechanical properties of the substrate. Finally, the problems of long term corrosion protection will be examined in terms of the practicalities of reclaiming and recoating of ex-service turbine parts with a view to extending component life and conservation of critical materials.
Bibliographic Reference: MATERIALS SUBSTITUTION AND RECYCLING, VIMEIRO (PORTUGAL), OCT. 9-14, 1983 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31150 ORA
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Record Number: 1989122044800 / Last updated on: 1987-01-01
Available languages: en