Abstract
This paper reports interactions between corrosion and solid particles erosion in slurry conditions. The materials tested in this investigation are intended to be used as hardfacing protective overlays in critical areas of the hydrotransport process in the oilsands industry, where erosion-corrosion can dramatically reduce the pumping and piping equipment lifetime. The materials under investigation were: two Ni-based and one Fe-based metal matrix composites (MMCs) with tungsten carbide (WC) as the reinforcing phase. The microstructure of the overlays was analyzed and mainly comprised a matrix phase with the presence of embedded intermetallics and the WC reinforcing phase grains. The corrosion behavior is assessed as a function of temperature, the Ni-based MMCs showed a pseudo-passive behavior at low temperature; however at high temperature their corrosion resistance was dramatically reduced. In contrast, the Fe-based MMC showed active corrosion behavior. The erosion- corrosion degradation mechanisms were assessed as a function of sand loading and aqueous environment. It was found that the presence of intermetallics in the matrix phase and around the WC grains played an important role in the erosion-corrosion performance of the MMCs overlays. At low sand loading and high temperature, the corrosion behavior of the MMCs dramatically affected their erosion-corrosion performance, whereas at high solid loading and low solution corrosivity, the microstructural features and matrix microhardness of the overlays determined their erosion-corrosion performance.
