TL;DR: In this article, cathodic arc ion plated chromium nitride (CrN) coatings were deposited on WC-Co substrates at negative substrate bias voltages in a range from 0 to 200 V. The performance of CrN-coated endmills in copper was also investigated correlating with the properties.
Abstract: Cathodic arc ion plated chromium nitride (CrN) coatings were deposited on WC–Co substrates at negative substrate bias voltages in a range from 0 to 200 V. The properties of CrN coatings were investigated, including the structure, hardness, adhesion and residual stress. The performance of cutting tests of CrN-coated endmills in copper was also investigated correlating with the properties. At a negative substrate bias voltage of 30 V, the adhesion strength of the coating was maximized, and the grain size became relatively small. The endmill deposited at the same bias voltage exhibited the best cutting performance of all the other samples. The cutting performance of CrN-coated endmills were superior to that of (Ti,Al)N coated endmills or uncoated endmills. The relationships between the cutting performance and film properties were discussed in terms of the wear system of the cutting tools.
TL;DR: In this article, a phase transformation from CrN+Cr(2)N + CrN-->CrN+ Cr(2)-N+Cn+Cr+CrN was shown to change from 200 to 220 degrees and the preferred orientation of the chromium nitride was changed from (200) to (220).
Abstract: Cr-N coatings were deposited on 1Cr18Ni9Ti stainless steel in the pure N(2) atmosphere by arc ion plating (AIP). The relationships between deposition parameters and coating properties were investigated. X-ray diffraction showed a phase transformation from CrN+Cr(2)N+Cr-->CrN+Cr-->CrN and the CrN preferred orientation changed from (200) to (220) as N(2) pressure increased. Increasing bias voltage led to CrN preferred orientation changed from (200) to (220) and the formation of Cr(2)N. XPS results indicated that chemical composition of the coatings changed as N(2) pressure increased but it changed little with bias voltage. The lower melting point of chromium nitride formed on target surface induced the increase of macroparticles and deposition rate with increasing N(2) pressure; and bias voltage had an obvious effect on reducing macroparticles of the Cr-N coatings. Residual stresses were measured by substrate curvature technique, and the changing tendency coincided with the microhardness of the coatings. (C) 2009 Elsevier B.V. All rights reserved.
TL;DR: In this article, the microstructure, mechanical properties, fracture toughness and adhesive strength were investigated via X-ray diffraction (XRD), nanoindentation and micro-scratch tests.
Abstract: CrN, CrTiN, CrAlN and CrTiAlN coatings were deposited on Si (100) wafers, and their microstructure, mechanical properties, fracture toughness and adhesive strength were investigated via X-ray diffraction (XRD), nanoindentation and micro-scratch tests. Besides an F.C.C. crystal structure, TiN0.3 (004) and AlN (222) phases were found in the CrTiN and CrAlN coatings while the crystallinity of the CrTiAlN coating decreased. The hardness of the CrN (14.5 GPa), CrTiN (13.9 GPa) and CrAlN (17.7 GPa) coatings was determined by their grain sizes while the CrTiAlN coating with the most compact morphology exhibited the highest hardness of 22.0 GPa. In addition, CrTiN (KIc = 2.73 MPa· m ), CrAlN (KIc = 2.70 MPa· m ) and CrTiAlN coatings showed a stronger crack resistance than the CrN coating (KIc = 1.06 MPa· m ), especially the CrTiAlN coating without any radial cracks. However, the CrTiAlN coating encountered circumferential cracks and premature delamination (Adhesive energy Gc = 70 J/m2) because of its highest compressive stress (4.64 GPa). Based on the results here, it is concluded that a decent compressive stress of 3.0 GPa is expected to help thin films prevent from radial and circumferential cracks simultaneously.
TL;DR: In this paper, a bipolar symmetric pulsed DC magnetron reactive sputtering process at 2 kHz and 20 kHz pulse frequencies was used to prepare chromium nitride coatings.
TL;DR: The surface roughness of these coatings were investigated by atomic force microscopy (AFM) and the adhesion force was measured using direct tensile pull-off test apparatus as discussed by the authors.
Abstract: The sticking of product material to injection molding tools is a serious problem, which reduces productivity and reliability. Depositing alloy nitride coatings (TiN, ZrN, CrN, and TiAlCrN) using closed field unbalanced magnetron sputter ion plating and electrodeposition of chromium, and characterizing their surface free energies in the temperature range 20–120 � C have led to the development of a non-sticking (with a low surface free energy) coating system for semiconductor IC packaging molding dies. The contact angles of water, diiodomethane and ethylene glycol on the coated surfaces were measured at temperatures in the range 20–120 � C using a Dataphysics OCA-20 contact angle analyzer. The surface free energy of the coatings and their components (dispersion and polar) were calculated using the Owens-Wendt geometric mean approach. The surface roughness of these coatings were investigated by atomic force microscopy (AFM). The adhesion force of these coatings were measured using direct tensile pull-off test apparatus. The experimental results revealed that TiAlCrN, CrN and ZrN coatings outperformed Hard-Cr and TiN coatings in terms of anti-adhesion, and thus have the potential as working layers for injection molding industrial equipment, especially in semiconductor IC packaging molding applications. [doi:10.2320/matertrans.47.2533]
TL;DR: In this article, the authors reported experimental results on increases in hardness of sputtered PVD CrN coatings by means of additions of varying content of Ag or W. The results showed that the hardness of CrN increased with increasing W content; reversely, that of Cr-Ag-N decreased with increasing Ag content.
Abstract: Practice has proven that CrN performs better than TiN under some specific tribological applications. Nevertheless, the relatively soft nature of CrN still remains a problem. This paper reports experimental results on increases in hardness of sputtered PVD CrN coatings by means of additions of varying content of Ag or W. The resulting Cr–Ag–N and Cr–W–N coatings, grown on JIS SKH51 steel substrates, were characterized using SEM, EDS, WDS, XRD, micro-indentation hardness testing and scratch adhesion tests. Moreover, wear behavior was studied on two types of tribometer, employing different contact regimes — a ‘cylinder-on-disk’ line-contact reciprocating-sliding regime and a ‘ball-on-disk’ point-contact rotating-sliding regime. The experimental results can be summarized as follows: The hardness of Cr–W–N coatings increased with increasing W content; reversely, that of Cr–Ag–N coatings decreased with increasing Ag content. The additions of Ag and W resulted in a formation of secondary phases, elemental Ag and WN, respectively, uniformly embedded in the CrN coatings. With the two different types of tribometer, the observed trends for wear behavior, wear and friction coefficient, were nearly identical, indicating that both Ag and W additions to CrN coatings were beneficial. However, the Cr–W–N coatings were significantly more wear resistant than the Cr–Ag–N coatings. With the addition of W at 6.8 at.%, the largest wear improvement of 73%–85% was achieved.