Influence of HPPMS pulse parameters on the stoichiometry and the formation of reaction layers on nitride hard coatings for cutting applications

• Applicant: Professorin Dr.-Ing. Kirsten Bobzin
• Subject Area: Coating and Surface Technology ; Metal-Cutting and Abrasive Manufacturing Engineering
• Term: from 2016 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 321041164

During the machining of powder metallurgical high-speed steel, abrasive and adhesive wear as well as oxidation occur as damage mechanisms on the tools. The application of TiAlCrSiON coatings by means of high power pulsed magnetron sputtering is a promising approach to increase the tool life. During the last research period, the chemical composition and pulse parameters of those coatings were correlated with the formation of the reaction layer. Moreover, the damage mechanisms due to thermal load and the diffusion behavior against steel were investigated comprehensively. Furthermore, milling tests were carried out under practical conditions. While the interaction between the coatings and steel was investigated under high thermal and purely static load so far, analysis of the tribological behavior of the coatings under dynamic load was not yet planned in the previous research period. However, investigations in the current state of the art show that the use of oxynitride hard coatings can reduce friction against steel under dynamic load. The overall aim of the research period now applied for is to gain knowledge about the influence of the chemical composition of TiAlCrSiON nanocomposites on the interaction with steel under tribological load and on the damage collective in machining. After coating deposition, an influence of the chemical composition on the coating properties is investigated. Moreover, the relationships between the coating properties, the frictional behavior and the formation of reaction layers are investigated in tribological system tests. It is also investigated whether wear can be reduced in the system tests by increasing the aluminium and oxygen content. Finally, it will be investigated whether the correlations found in the system tests can be transferred to field tests. Here, the extent of the fundamental damage mechanisms in the machining process is investigated as a function of the frictional behavior.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Tobias Brögelmann