X-ray Diffraction in Conservation

An analytical method that identifies the crystalline phases in a material from the angles at which X-rays diffract off its lattice, used in artifact conservation to determine corrosion products and minerals. On the Mary Rose (sunk 1545, raised 1982), XRD identified iron-sulfur and chloride corrosion compounds in the waterlogged oak and iron, guiding the PEG and desalination treatment. It distinguishes, for example, akaganeite from other iron oxyhydroxides, which matters because akaganeite drives continued corrosion in marine iron after recovery.