第2回　ナノ材料科学環境拠点セミナー

Hard Nanocomposite Coatings:

Dr.Joerg Patscheider

スイス連邦素材研究所（EMPA）

Ternary metal nitrides and carbides with appropriate nanostructures successfully promote hardness, oxidation resistance, improved wear behavior and other properties relevant for protective coatings. Examples are nc-TiN/a-Si3N4 and nc-TiC/a-C:H which are composed of distinct nanocrystalline (nc-) and amorphous (a-) phases. Most nanocomposite hard coatings with well-separated phases show a hardness maximum, as the composition is changed from the pure polycrystalline phase to compositions dominated by the amorphous phase. At the hardness maximum the domain size of the nanocrystalline phase is below 10 nm and the average thickness of the tissue layer separating the nanocrystals, amounts on an average to only one to two atomic bond lengths. Mutual solubility often leads to interfaces with gradual transitions between the constituting phases. The quality of the resulting interfaces and that of the tissue phase in terms of structural perfection and thickness is of decisive influence for the performance of the coatings.