Development of Gas-to-Liquid projects requires processing systems which can promote an aggressive
form of high temperature corrosion attack called metal dusting. Nickel alloys containing high levels of
chromium and aluminium are shown to be most effective in resisting this form of corrosion among
wrought materials. A single material appraisal for use of one such material, alloy 693, has recently been
granted, allowing its use beneath the temperature of time-dependency. The methodology behind
obtaining this approval will be explained. Metal dusting corrosion behaviour of several nickelchromium
materials will be described.