Abstract
It has been known by the present authors that some projections and inclusions are often observed on CVD coated films and in the same films on cemented carbides substrate, respectively. The characteristics and the source of inclusions were mainly studied, using commercially available coated cemented carbides tools for cutting steels, and specimens prepared in the authors' laboratory. The results obtained were as follows. The projections were closely related to the inclusions, because projections usually developed just over inclusions. The inclusions were the small particles consisting of TiC, TiN, etc. It was considered that, during CVD, the substance crystallized on the inner surface of carbon-tray (for setting samples) was broken, and produced fine particles were transferred with gas flow to the substrate surface, resulting in the inclusions wrapped in the films. The size and number density of projections or inclusions varied depending on the location of substrate surface in relation to the direction of gas flow.
