MEASUREMENT OF STRESS IN NICKEL-OXIDE LAYERS BY DIFFRACTION OF SYNCHROTRON RADIATION

The average in-plane stress in a number of polycrystalline NiO thermal oxidation scales has been measured by the sin2-psi technique at the Synchrotron Radiation Source, Daresbury, using the high-resolution diffractometer 8.3, which exploits parallel-beam X-ray optics. There are a number of distinct advantages for stress measurements using this arrangement. Shifts in peak positions of much less than 0.005-degrees can be accurately measured, and the tunability of the incident radiation allows control over the depth of penetration of the X-rays into the surface of the specimen.