Structure of TiB2 produced by dynamic ion mixing

Article abstract of DOI:10.1016/0022-5088(88)90305-0

The technique of dynamic ion mixing is based on the use of a high energy ion beam to homogenize at the atomic scale and to improve the adherence of a growing film on any substrate. TiB₂ films of stoichiometric composition were produced either by co-evaporation or by dynamic ion mixing using 100 keV Ar⁺ ions. The characterization of the films was performed by transmission electron spectroscopy (TEM). The ion mixing of the growing film has a crucial importance with regard to the resulting microstructural state. Amorphous TiB₂ films are produced by conventional co-evaporation although crystalline TiB₂ films of hexagonal structure are produced by dynamic ion mixing. The TiB₂ amorphous phase appears to be very stable since crystallization starts only at about 1170 K, and complete transformation into the hexagonal crystalline structure is obtained at 1280 K. Relatively thick TiB₂ coatings have been prepared with e=1 μm and studied by TEM on cross-sectional preparations. The microhardness of crystalline TiB₂ films is about 2800 kgf mm^-2 and is in good agreement with the value reported for bulk TiB₂.