The cavitation erosion performance of Nickel 200 was used to calibrate the equipment at the University of Southampton. The incubation period was also investigated along with a comparison of a range of materials. including steel, ceramics, carbide and PEEK.
Comparison with ASTM G32
In order to normalise the erosion test rig with the ASTM G32 standard, Nickel 200 (UNS N02200) has been tested. The results were compared to the results detailed in Figure 5 of ASTM G32 – 16 , which provides cumulative erosion time curves for Nickel 200 to determine a multiplication factor to be applied to normalise results with the standard.
In order to assess the incubation period the surfaces were examined employing SEM images after 30 and 60 minutes. The top row of images shows the surface profile prior to testing, where machining lines can clearly be seen. After 30 minutes the surface appears to be indented and this is clearly shown in the backscattered images with the machining line of the original nickel surface following the pattern of the indents. After 1 hour fractures on the surface have begun to appear along the machining marks of the original nickel surface, which are still visible.
Comparison of Materials
The cavitation characteristics for various materials have been carried out in order to rank their performance. Materials such as tungsten carbide and zirconia exhibited low rates of erosion, whereas HTCS has a shorter incubation period and a lower maximum rate of erosion compared with duplex stainless steels. The maximum mean depths of erosion was found to be for PEEK materials
“Cavitation Erosion Performance of Steel, Ceramics, Carbide, and Victrex PEEK Materials”, Materials Performance and Characterization, Vol. 7, No. 5,2018, pp. 1093–1106, https://doi.org/10.1520/MPC20180027. ISSN 2379-1365