Potenzial der High-Speed Physical Vapour Deposition Technologie zur Abscheidung oxidischer Werkzeugbeschichtungen

  • Potential of High-Speed Physical Vapour Deposition Technology for the Deposition of Oxide Tool Coatings

Welters, Martin; Bobzin, Kirsten (Thesis advisor); Mayer, Joachim (Thesis advisor)

Düren : Shaker Verlag (2021)
Book, Dissertation / PhD Thesis

In: Schriftenreihe Oberflächentechnik 67
Page(s)/Article-Nr.: XV, 167 Seiten : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2020

Abstract

The processing of new materials in machining, metal forming and casting processes is accompanied by increasing demands on tools when handling e.g. titanium alloys, high-strength and high-temperature-resistant alloys or fibre-reinforced materials. During the treatment of the materials, cutting and forming tools are exposed to complex stress collectives in which mechanical, chemical and thermal loads are superimposed. Conventional tool materials can only withstand these complex stresses to a limited extent, which is why the deposition of thin coatings on tools has become established in the industry over the past decades. Due to its excellent high-temperature properties and hot hardness, α-Al2O3 is a promising coating material for increasing the service life of production tools. However, industrial synthesis is conventionally carried out by chemical vapour deposition (CVD) at temperatures T ≥ 800 °C, which considerably limits the choice of substrate materials. Due to technological and material-specific properties the combined application of high-speed physical vapour deposition (HS-PVD) technology and the deposition of (Al,Cr)2O3 coatings represents a promising alternative to α-Al2O3-CVD coatings. The aim of the systematic variation of process parameters carried out in this work is to obtain fundamental process and coating-related knowledge concerning the deposition of (Al,Cr)2O3 coatings by means of HS-PVD technology at moderate temperatures. The variation of the substrate temperature, the O2 reactive gas flow and the bias voltage enables the definition of processes for the deposition of promising (Al,Cr)2O3 coatings concerning the application on production tools. Moreover, analyses are performed to investigate the properties of (Al,Cr)2O3 coatings in detail. Additionally, the challenges during the deposition of oxidic coatings by means of HS-PVD as well as the capacity of the technology for the deposition of thick, s ≥ 10 µm, oxidic hard coatings under stable conditions are evaluated. The planned use of (Al,Cr)2O3 coatings on cutting and forming tools requires sufficient thermal stability. Therefore, corresponding investigations are performed. Furthermore, the potential of HS-PVD technology regarding the homogeneous coating of internal surfaces by means of the convective particle transport is discussed and evaluated in this work.

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