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 10,000 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.