Properties of (Ti,Al)N coatings deposited by the magnetic filter cathodic arc

A newly devised magnetic solenoid filter retrofitted in the cathodic are plating system demonstrates that it can effectively reduce the number and size of the numerous macroparticles that are usually present on the surface of the coatings deposited by the conventional cathodic are plating system. However, the magnetic solenoid filter tends to alter the composition and properties of the coating deposited. The (Ti,AI)N coatings produced were evaluated in terms of surface properties, color dispersion, elemental content and oxidation behavior. The properties derived for the coatings were categorized according to the position of the coating specimens with respect to the central axis of the target. It was found that the properties of the coatings deposited in this system are symmetric about the central axis of the cylindrical target. In other words, specimens located along the central axis of the cylindrical target were found to be higher in Ti content (28 at.%) and lower in Al content (19 at.%). By comparing the elemental content with the results of colorimetry analysis for the coatings, it was found that the color of the coating is blacker and greener when Al content is higher, and is whiter and redder when the Ti content is higher. The result of thermogravimetry shows an improved oxidation resistance for the coatings having higher Al contents. (C) 2000 Elsevier Science B.V. Al rights reserved.