Abstract
During chemical vapour deposition (CVD) process the surface properties of the metallic or non-metallic materials are modified by the generation of a new layer with special chemical and physical properties. This modification in the surface properties is produced by subjecting the substrate materials to a single gas or a combination of gases at elevated temperatures. One type of CVD process is carried out in a heated retort and the chemical reactions that occur are initiated in the space around or on the surface of the substrate. In the present paper, titanium nitride layers on widia substrate have been obtained by an original CVD method, in a heat treatment chamber. Thin layers of 1·5–10 μm using ferrotitanium as raw materials were obtained as a function of exposure time at 1050°C. The microhardness of the coated materials ranges between 25 000 and 25 520 MPa. Although widia is well known as a very good material for cutting devices, cutting experiments on these coated widia plates show that the endurance increases by 3 to 5 times as compared with that of uncoated plates.
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