Laboratory tests for hot-corrosion studies

Abstract

To simulate and study hot corrosion in gas turbines various testing procedures have been developed. The first category of test corresponds to sample immersion in molten salt. These crucible tests were developed to allow fast ranking of the alloys. They have been almost totally abandoned in their original form, but they have led to more sophisticated testing methods involving electrochemical measurements. In the second category it is attempted to reproduce the conditions prevailing in burner rigs, i.e. continuous salt deposition on the testpieces. This is achieved using either sample contamination by spraying a Na2SO4 aqueous solution, followed by oxidation, or the modified Dean method (condensation of Na2S4 vapour produced in the hot zone of a gradient furnace).MST/289