Abstract
Au films were prepared on iron substrate by electroless plating using Al as a galvanic contact material, and their formation mechanism and morphology were studied by direct examinaticn and diffraction of electron microscope.
The results obtained were as follows:
1) The coherencies found between initial Au crystals and Fe substrate were as follows.
(1){(001) Fe||(001) Au [110] Fe||[010] Au (2){(110) Fe||(110) Au [001] Fe||[110] Au
With the lapse of plating time, crystal orientations different from such coherencies were observed in some parts.
2) The coherency between Au-particles of under 100Å in diameter and iron substrate had already been found. In the early stage, these Au-particles were separated one another; but with the lapse of time, they were combined and developed to network structure. Sometimes, micro-twins or moiré patterns were observed in the connecting parts of network structure.
3) Extra reflections due to double diffraction were observed in the diffraction patterns of Au plate crystals. They were explained as follows: there was co-existence of two or more Au crystals having different orientations.
4) Micro-twins and rotating moiré patterns were observed in the electron micrographs of Au plate crystals. The micro-twins contributed to the relaxation of stress due to lattice defects of Au crystals. The rotating moiré patterns indicated the rotation of Au crystals in the plate crystal and the rotation contributed to the relaxation of stress in the crystal.
