Guide to the control of high temperature corrosion and protection of gas turbine materials

Abstract

Components of hot sections in gas turbines are subjected to severe thermomechanical cycles and operate in complex environments which depend on the type of machine and conditions of use. Environment-induced degradations if not controlled may cause a significant decrease in the components expected lifetime. The aim of this work is to show how to control hot corrosion processes or to decrease corrosion attack which affects these components. This report is directed to non-specialists. It is intended to give some basic knowledge on hot corrosion so that the users for instance can orientate themselves towards a solution and especially communicate in a meaningful way with specialists. It is based mainly on results collected from the 'COST' work, which represents about 12 years of collective effort of the European Communities in this field. The report covers the background to the problem, the description of the basic corrosion processes and the way to study them, the materials and coatings currently used for blades and vanes, the effect of environment and coating on components' mechanical properties and finally the prevention of corrosion and solutions for the future.