In situ structural evolution of arc-deposited Cr-based coatings

Abstract

Cr-based coatings were prepared by cathode arc evaporation technology using N 2 and C 2 H 2 as reactive gases. Three compositions were investigated, Cr 60 N 40 , Cr 41 N 27 C 32 and Cr 67 C 33 .The present investigation is centred on the structural stability via coatings tempering up to 1000ºC, by in situ X-ray diffraction in inert atmosphere. As-deposited coatings present low order structure with a medium feature size less then 10 nm. The hexagonal β-Cr 2 N phase, characteristic of binary Cr 60 N 40 coating, was stable up to 900ºC, before recrystallization and grain growth takes place. For Cr 41 N 27 C 32 film the phase transition varies from the metastable δ-Cr(N,C) to orthorhombic chromium carbonitride Cr 3 (C x N 1-x ) 2 phase up to 800ºC and then to chromium carbide phase. No chromium nitride phases were detected in spite of the similar N and C contents after the deposition. The Cr-C coating recrystallizes into a mixture of carbide phases, mainly Cr 3 C 2 and Cr 23 C 6 after 1000ºC annealing treatment.

Effect of annealing treatment on the microstructure, mechanical and tribological properties of chromium carbonitride coatings

“…These values are close to that obtained by Ibrahim et al [4] for CrN coatings deposited by magnetron sputtering. However, the film hardness is a little bit lower than that reported in the literature (19)(20)(21)(22)(23)(24) [12,32,33]. This may be attributed to the heat produced by high energetic ion bombardment [33].…”

“…Every time the annealing temperature rises, we stimulate the migration of a greater amount of carbon atoms to the film, which leads to the observed increase of the (410) Cr 7 C 3 peak intensity. This carbide is the most stable and the hardest among all the other carbide phases, especially when it is used as a coating for high carbon steel [6,17,20]. From Fig.…”

The effect of temperature and sliding distance on coated (CrN, TiAlN) and uncoated nitrided hot-work tool steels against an aluminium alloy

“…Due to the transferred aluminium alloy the forming process must be interrupted and the die's bearing surface, cleaned using silicon carbide abrasive paper and, on occasions, chemical solutions must be used, which can cause damage to the die surface and deteriorate the dimensional and geometrical tolerances of the product [5]. To improve the service life of the forming tools and the quality of the product, the surfaces of the tools can be coated with thin, hard coatings, which can operate at high temperatures [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. With the use of protective layers such as CrN and TiAlN in the contact, and with different counter materials, the coefficient of friction can be reduced by as much as 30%, compared to the hot-work tool steel that is typically used in forming applications [5,[21][22][23][24][25][26][27][28][29][30][31][32].…”

Ion bombardment-induced nanocrystallization of magnetron-sputtered chromium carbide thin films

“…However, due to the environmental pollution that may be caused by these methods [11], recent investigations have been focused at various physical vapor deposition (PVD) techniques such as sputtering [1,3,[6][7][8][11][12][13][14][15], pulsed laser deposition [16] and arc evaporation [3][4][5]17,18] as well as chemical vapor deposition (CVD) techniques [19].…”