Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Laure Libralesso"

A comparative research on mechanical properties of monolayer, gradient and multi-module coatings on CrN(C) base DOI:10.15199/28.2018.1.2

  1. INTRODUCTION Chromium is used for decades for producing relatively thick, hard, anti-wear coatings in a variety of industries, including automotive and aerospace industries. However, the chemicals used for the deposition of these coatings contain hexavalent chromium (Cr6+ ions), and chromium in this state is extremely toxic. Therefore, in relation to the European directive concerning chemicals (REACH), hard chrome coatings, produced in toxic and carcinogenic baths, must be replaced by “green" solutions. After this period, the application of these technologies will be significantly limited. In the aerospace industry, in some applications, coatings produced by Physical Vapour Deposition (PVD) methods may be an alternative to hard chrome coatings [1÷3]. However, it should be noted that current practice in the designing of safe aircraft structures is the assumption, that the design should be resistant both to damage at a certain level (damage tolerant design) and have a degree of redundancy that will prevent the catastrophe in the case of total dysfunction of any part (fail-safe design). For this reason, in cases where it is necessary to take into account the resistance to accidental impacts, or impacts resulting from way of functioning of specific mechanisms, on parts subjected to such operations, are typically created composite surface layers. The best known and most widely used technology of surface treatment, capable of producing a composite layer, is a combination of gas or plasma nitriding process with deposition of hard, anti-wear coatings by PVD methods (duplex technology). The result of such configured technology is composite layer composed of nitrided layer and formed directly on its surface PVD coating. One of the first flagship works, indicating the synergistic effects resulting from sequential combination of nitriding processes with PVD deposition of thin coatings is the work of Sun and Bell [4], which contai[...]

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