ICMCTF2001 Session G4-2: Hard and Hybrid Coatings for Cutting and Forming Tools, and Surface Engineered Components

As previously reported the properties of MoS₂ coatings can be improved by the co-deposition of a small amount of titanium. These MoS₂ /Ti coatings known as MoST^TM, are harder, much more wear resistant and also less sensitive to atmospheric water vapour than pure MoS₂. These coatings have given excellent industrial results for a wide range of cutting and forming applications.

Plastic, glass and metallic (stainless steel, high speed steel…) substrates have been coated and rubbed against various counterparts (Al, bronze, stainless steel, Chrome steel, WC…balls) in pin on disc and reciprocating wear tests at several loads (from 5N to 100N) and under several conditions (humidity, oil, water…) and their friction and hardness have been reported. Different counterparts as well as the coated samples have been studied and the wear has been measured on both ball and coating. A comparison with traditional hard coatings such as TiN, TiCN, TiAlN, CrN, MoN, ZrN and CrC/C has shown that MoS₂/titanium composite coatings not only have lower friction, but also allow a protection of the counterpart.

This paper will an extension of the results presented at ICMCTF 2000- San Diego (USA), 10-14 April 2000.

Thin film oxide coatings are of more and more interest in the last years` thin film developments. Due to high binding energies oxide materials are highly resistant against adhesive wear. Furthermore, with increasing temperature the sliding coefficient decreases and the hardness reduction is slowly. This leads to high abrasion resistance and a high potential for dry machining applications.

This paper describes the development of deposited Al₂O₃, ZrO₂, CrO and TiZrO multilayer coatings using a combined DC/RF Sputter Ion Plating process. All coatings were applied under production conditions at moderate temperatures below 400°C in order to coat HSS as well as cemented carbide tools. Different layer arrangements and main metallographic data are presented. Furthermore,results of tribological tests and first performance tests in dry machining operations are shown.

Dry and high-speed machining of non-ferrous lightweight materials is becoming increasingly important, e.g. for a new generation of vehicles, due to environmental considerations etc.

The present paper summarizes the results of dry drilling experiments, which have been executed to evaluate the performance of a new super-hard coating (Diamor) in comparison to a commercially available TiAlN coating and uncoated hard-metal tools. The machined material was aluminum 6061, a standard off-the-shelf material used in numerous applications in the aerospace and automotive industries. The machine tool used was a three axis Chiron FZ 28 L. A full-factorial two-level statistical experimental design, including a center point for the two factors cutting speed (140 ..180m/min) and feed rate (0.3 ...0.5 mm) has been applied. All of the experiments have been repeated once for statistical purposes. The drill diameter, as well as the depth of the drilled holes, was 10 mm. The total cutting length based on breaking of the tools has been evaluated. The Diamor coated tools performed more than 100% better compared to TiAlN for almost all of the tested parameter combinations.