TiN coating on wall of holes and stitches by pulsed DC plasma enhanced CVD

TiN coating samples with narrow-stitch or deep-hole of different sizes and real dies with complex shape were processed by a larger-scale pulsed plasma enhanced CVD(PECVD) reactor. Scanning electron microscopy, optical microscopy, Vicker's hardness and interfacial adhesion tests were conducted to find the relation between the microstructure and properties of TiN coating on a flat and an inner surface. The results indicate that the inner-wall of holes (d>2 mm) and inner surface of narrow-stitches (d>3 mm) can be coated with the aid of pulsed DC plasma in an industrial-scale reactor. The quality of coatings on different surfaces is almost the same. The coating was applied to aluminum extrusion mould, and the mould life was increased at least by one time.