THERMAL-STABILITY OF NANOCRYSTALLINE GOLD STUDIED BY X-RAY-DIFFRACTION METHOD

Grain size of nanocrystalline Au specimens prepared by the gas deposit ion method was measured by means of X-ray diffraction. The grain size of as-prepared specimens, estimated by the Warren-Averbach's method, w as in the range of 7 to 11 nm and no apparent dependence on the evapor ation temperature (1700-1850 K) and the He gas pressure (0.085-0.186 M Pa) in the evaporation chamber was found. The thermal stability of the se specimens was found to be quite high; when annealed for 1 h, the gr ain size remained unchanged up to 770 K, grew about twice at 1070 K an d showed a rapid growth above that.