κ-alumina films were deposited on WC-Co alloy by a CVD method with an under layer of TiC. Powder samples were also prepared by disolving steel sheets on which TiC/Al₂O₃ or TiC/Al₂O₃/TiN were deposited. These specimens were examined by X-ray diffraction to obtain more exact diffraction data for practical use.
Diffraction profiles of the films and the powders were analyzed with a hexagonal system. CVD-coated films showed strong orientation, namely c-axis being rectangular to the film plane. κ-Al₂O₃ has lattice constants of a₀=9.632A and c₀=8.929A as a hexagonal system. These values correspond to a₀=4.816A, b₀=8.342A and c₀=8.929A of an orthorhombic system.