In the present work new coating materials have been tested in
laboratory conditions simulating high temperature corrosion in biomass
boilers and waste incinerators with molten salt deposits. The work also
included some thermodynamic modelling and high temperature erosion testing.
In the deposit corrosion tests the dense Ni- and Cr-based materials performed
somewhat better than iron-based materials in means of corrosion. In the
porous coatings corrosion had propagated into the coating through the pores.
Inconel 625, as well as some of the other high Ni-materials, had good
corrosion resistance, but the coating detached from the low alloy steel
substrate material in many cases. Welded materials (MIG, laser) formed a very
dense coating and therefore reacted like bulk materials and HVOF coatings
were denser than arc sprayed coatings. It can be concluded that tough and
dense coatings succeed best in the erosion conditions. However, due to their
lamellar structure coatings are very sensitive to the size of erosive
particles and the impact angle. The thermodynamic modelling supported quite
well the corrosion test results, in spite of some weaknesses in the
databases, e.g. content of boron. The new salt database used in some
modelling cases gave good results, but should be applied with some caution.
|Conference||BALTICA VII - International Conference on Life Management and Main-tenance for Power Plants|
|Period||12/06/07 → 14/06/07|