硬質膜の傾斜機能コーティング機構の解明

抄録

Coating of cutting tool tips is demanded to obtain not only good surface properties but also good adherence to a substrate. The former are related to high stability and high strength, and the latter to bonding characteristics between film layer and substrate. WC-TiN gradient coating was conducted by rf magnetron sputtering using multi-S-guns. In order to explain the gradient coating mechanism, various analyses were carried out : X-ray diffraction for inspection of crystalline structures, Auger electron spectral analysis for inspection of chemical compositions, and scanning electron microscopy for observations of sectioned film layers. Two mechanisms play important roles in improving the bonding characteristics. One is that sputter-deposited elements of each layer are composed of the same crystalline structure as NaCl. The other is that some carbon from WC diffuses into the substrate. The deposition of β-WC_1-x, in a stable state at high temperature, is due to rapid cooling and removal of partial carbon.