Corrosion tests on austenitic samples with alumina and alumina-forming coatings in oxygen-containing stagnant Pb and turbulently flowing PbBi

Two differently produced alumina coatings (by pulsed laser deposition (PLD) and detonation gun (DG)) and one alumina-forming coating realised by pack cementation are proposed as a protection barrier against corrosion of austenitic steels in Pb and PbBi. Samples were tested in oxygen-controlled stagnant Pb (10−7 wt.%) at 480°C and 550°C for up to 10000 h and in turbulently flowing (up to 1.6 m/s) PbBi eutectic at 490°C with 10−9 – 10−8 wt.% oxygen for about 500 h. All exposed coatings showed a good behaviour in flowing PbBi and in stagnant Pb at around 480°C independent of the oxygen content. At 550°C, the PLD coating failed most probably due to incomplete coating of the sample, while the DG sample protected the base material.