Growth of WC–Cr–N and WC–Al–N coatings in a RF-magnetron sputtering process

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. a b s t r a c tTungsten carbide-based coatings have been used in a wide variety of industrial applications such as high speed cutting tools, extrusion dies, drills, aerospace industries, and more. A few reports on ternary and quaternary coatings of WC with other elements indicate good prospects for these material systems. The present study focuses on the formation of quaternary WCeCreN and WCeAleN coatings during the simultaneous reactive RF-magnetron sputtering of tungsten carbide and Al or Cr targets in an argon/ nitrogen gas mixture. The resulting coatings, with thicknesses of 3.5 mme8.2 mm, were characterized by using several analytical techniques including X-ray diffraction, SEM/EDS, AFM, and X-ray photoelectron spectroscopy. WCeCreN and WCeAleN coatings with high levels of tungsten (i.e. more than 50 at.% of the total metal content) demonstrated dense microstructure. Coatings with lower tungsten content formed columnar grain microstructure, with different surface morphologies depending on the process parameters. It was proposed that crystalline tungsten carbide (with partial N-substitution of C atoms) and chromium (or aluminum) nitride phases coexist in the coatings when the amount of tungsten was greater than 50 at.% of the total metal content; while at lower tungsten content, the dominating crystalline phase is either W-doped CrN 1Ày or AlN 1Ày solid solution, with WC 1Àx and small amounts of free sp 2 -bonded carbon present as X-ray amorphous phases.

Investigation on WC–Al composite coatings of AZ91 alloy by mechanical alloying

“…Owing to its high melting point, superior hardness, low friction coefficient, considerable elastic modulus, small thermal expansion coefficient and high thermal resistance, WC has been used in a wide range of applications, especially for use as high temperature working device. 14,15 Nowadays, many researchers have studied the composite coatings of WC-Cr, 15 WC-C, 16 WC-Co, 17 WC-Ni, 18 WC-TiC, 19 Ni-Al/BN/WC-Co, 20 etc. Mechanical alloying (MA) is a high energy ball milling technique utilising various types of mills in which a mixture of different powders is subjected to highly energetic compressive impact forces.…”