The corrosion behavior of two-phase Ni–Dy alloys in a eutectic (Li,K)2CO3 mixture at 650 °C

The corrosion behavior of binary Ni-Dy alloys containing 1, 3 and 5 wt.% Dy in a eutectic (0.62Li,0.38K)(2)CO3 mixture at 650 degreesC has been investigated. The alloys are two-phase composed of alpha-Ni solid solution and intermetallic compound DY2Ni17. The experimental results indicate that the corrosion rate of the three Ni-Dy alloys is significantly lower than that of pure Ni, forming a scale mainly composed of NiO together with a small amount of dysprosium oxides. The weight gain of the alloys changes little with the content of dysprosium, while the thickness of the scale decreases with increasing content of dysprosium. The presence of Dy can promote the lithiation process of NiO during immersion in the melt. The corrosion mechanism of the alloys is also discussed. (C) 2004 Elsevier Ltd. All rights reserved.