Mon, 23 November, 2020
As part of the Geo-Coat project, laboratory testing has assisted in down-selection of the novel Geo-Coat materials. Weir Group’s dedicated erosion-corrosion laboratory testing facility has aided in understanding of the corrosive wear resistance of the Geo-Coat materials and has helped to identify the most attractive coatings for geothermal applications. The laboratory erosion-corrosion testing used a recirculating submerged impinging jet test apparatus, where a jet of slurry impacts the test surface. The test conditions were chosen to particularly aggressive (3.5%NaCl, pH4 HCl) in an attempt to simulate harsh conditions which can be experienced in geothermal components.
One coating system which has been a focus of the Geo-Coat project is based on High Entropy Alloys (HEAs) produced by laser cladding. One particular alloy has shown a noticeable increase in erosion-corrosion resistance compared to its substrate material – 17-4PH stainless steel. This HEA has shown a reduction of material loss of almost 33% under erosion-corrosion conditions. This promising coating system is one of the coatings which was down-selected for evaluation in in-situ geothermal environments.
Article courtesy: Dr Frazer Brownlie, Dr Trevor Hodgkiess, Dr Douglas Watson, Weir Group, UK