The sulfur iodine (SI) water splitting cycle for hydrogen production consists of three coupled chemical reactions, which includes the generation and decomposition of HI. The HIx environment is extremely corrosive and the severity increases with temperature. Immersion coupon corrosion screening tests were performed on materials selected from four classes of corrosion resistant materials: refractory metal, reactive metal, superalloys and ceramics. Of the materials tested, only Ta and Nb-based refractory metals and ceramic mullite can tolerate the extreme HIx environment. Severe pitting and dissolution was observed in two different reactive metal zirconium. A nickel based superalloy, C-276, also showed severe dissolution in HIx solution. The materials which showed good corrosion behavior will undergo further long-term immersion testing to assess performance. In addition, C-ring, U-bend and DCB test samples fabricated from qualified materials will be tested under stress corrosion conditions to investigate their crack initiation and growth properties. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.