TRANSMISSION ELECTRON-MICROSCOPY ANALYSIS OF THE ORIENTED DIAMOND GROWTH ON NICKEL SUBSTRATES

Transmission electron microscopy (TEM) was used to investigate the int erfacial microstructure and the phases that developed during the nucle ation and growth of oriented diamond on Ni by a hot filament process. Oriented Ni4C nuclei were identified by plan-view TEM in a sample quen ched during the nucleation stage. Likewise, the presence of the Ni4C p hase between the diamond and the Ni substrate was observed by cross-se ction TEM in samples grown for several hours. The orientational relati onship among the diamond, Ni4C, and Ni substrate was examined by selec ted area diffraction. Diamond and Ni4C interfacial phase had a good ep itaxial relationship, while the interfacial Ni4C phase and the Ni subs trate developed with a small misfit and rotation. Based on these exper imental results, the nucleation mechanism of oriented diamond growth o n Ni is proposed. (C) 1998 American Institute of Physics.