The present study has been conducted to investigate the interaction between erosion and
corrosion processes under high velocity multiphase conditions. Tests were performed on
martensitic stainless steel samples of grade UNS S42000. Pure erosion and pure corrosion as
well as erosion corrosion impingement tests were carried out at three different impact velocities
between 10 and 60 m/s. CO2 at a total pressure of 15 bar was used as the gas phase. The
sand content, with grain size below 150 µm, was 2.7 g/L brine. Artificial brine with a NaCl
content of 2.7 % at a gas liquid ratio of 20,000 (under standard conditions) was used as liquid
phase.
Damaged surfaces of specimens exposed to the high velocity multiphase flow were
investigated by stereo microscopy, scanning electron microscopy (SEM) and an optical device
for 3D surface measurements. Moreover electrochemical investigations according to ASTM G
61 were performed to determine electrochemical behavior of tested materials including critical
pitting potentials Epit and repassivation potentials Erepass. Furthermore, near surface near regions of tested samples were investigated by applying nanoindentation in an atomic force
microscope (AFM). Synergy effects as a function of impact velocity are quantified.
At impact velocities of 10 m/s a pronounced synergistic effect of erosion plus corrosion was
found, at high impact velocities this effect decreased due to domination of erosive damage.
Keywords: erosion, corrosion, erosion corrosion, multiphase flow, stainless steel