According to Plansee, laboratory tests carried out at the Vienna University of Technology, in the course of developing new PVD coatings for wear-protection applications, have proven that the use of molybdenum alloys significantly reduces wear during machining.
The service life of tools and coatings used in a wide variety of cutting processes is determined by wear such as adhesion and abrasion. Increasing the hardness is generally an effective approach to minimising abrasive wear, but Plansee states that this solution only works for a specific range of applications, and has no effect on those wear mechanisms that are related to adhesion.
In order to improve tool wear resistance and lifespan, Plansee, Oerlikon Surface Solutions AG and the University of Technology Vienna (TU Wien)’s Institute of Materials Science and Technology, have conducted a research programme into the effect of molybdenum on the wear behaviour of arc-evaporated Ti-Al-N coatings. The research was conducted at one of TU Wien’s Christian Doppler laboratories.
According to Plansee, the findings clearly showed that in situ formation of solid, self-lubricating phases such as MoO3 led to a significant reduction in adhesive and abrasive wear. The use of targets produced using powder metallurgical methods (Plansee Composite Materials GmbH) allowed the deposition of single-phase, face-centred cubic coatings with a Mo content of up to 12 at.%. This high alloy content also had a very positive impact during wear tests up to 700 °C.
Stefan A Glatz, Vincent Moraes, Christian M Koller and Helmut Riedl have released details of the research findings in a paper titled ‘Effect of Mo on the thermal stability, oxidation resistance, and tribomechanical properties of arc evaporated Ti-Al-N coatings’, published in the American Vacuum Society’s Journal of Vacuum Science and Technology and available to download here.