Mechanisms for chlorine induced high temperature corrosion studied by in-situ microscopy and first principle calculations

Research Project, 2015 – 2018

The aim of this project is to help increase steam data in power boilers burning renewable fuels, such as biomass and waste, which are much more corrosive than the dominating fossil fuels. The maximum steam temperature in these plants (and thereby their power efficiency) is limited by alkali chloride induced corrosion. The corrosion models we have today are insufficient, partly because of serious experimental difficulties. To overcome this obstacle new instrumentation and methods will be developed in this project. We will construct a novel in-situ laboratory (the Nano-CPM workstation) placed inside a Focused Ion Beam/Environmental Scanning Electron Microscope (FIB/ESEM). It has a unique combination of state-of-the-art sub-parts: (i) a specially designed small furnace for well-controlled in-situ studies, which enables viewing of the corrosion process as it occurs, on the nano-scale, at high temperature; (ii) a system with small micro-robots for handling the furnace and bulk samples before and after exposure; (iii) micromanipulators for preparing, handling and storing thin (100 nm) samples; and (iv) various optimized stations providing a unique arrangement of imaging, chemical and structural analysis on the nano-level. The combination with modelling using Density Functional Theory (DFT) methods for large band gap and semiconducting oxides will enable us to describe detailed mechanisms for alkali chloride induced corrosion, making it possible to find ways to reduce its damage.