Vapor‐Deposited Borides of Group IVA Metals

Abstract

The formation of vapor‐deposited TiB 2 , ZrB 2 , and HfB 2 at 1400°C was studied with respect to the influence of process variables on structure and stoichiometry. Stoichiometric, nonporous deposits of TiB 2 were obtained; ZrB 2 and HfB 2 deposits contained β‐rhombohedral boron. Precision lattice parameters were determined for the three diborides. The effect of codeposited boron on these parameters appeared to be slight. A small degree of preferred orientation existed in materials made under these conditions, indicating that crystallites tend to be deposited with c axes parallel to the substrate. Grain size, orientation, porosity, and stoichiometry are influenced and therefore should be controllable by process variation.