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Journal ArticleDOI

Structure and properties of cathodic arc ion plated CrN coatings for copper machining cutting tools

A. Kondo1, T. Oogami1, K. Sato1, Y. Tanaka1
05 Nov 2003-Surface & Coatings Technology (Elsevier)-Vol. 177, pp 238-244
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.
Citations
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Journal ArticleDOI
X. S. Wan1, Sumei Zhao1, Yeran Yang1, Jun Gong1, Chao Sun1 
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.

147 citations

Journal ArticleDOI
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.

135 citations

Journal ArticleDOI
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.

88 citations

Journal ArticleDOI
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]

50 citations

Journal ArticleDOI
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.

41 citations

References
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Journal ArticleDOI
TL;DR: In this article, the results and performance tests were compared with the available data, mostly published on forming, milling, deep drawing of copper, nickel and titanium and their alloys, and on die casting of aluminium and Al-alloys.
Abstract: Industrial applications of CrN (PVD) coatings are entering an expanding but selective range of mass manufactured goods. They may be prepared as single, low and high temperature CrN coatings and double TiN+CrN coatings. In this work, depositions of CrN at high temperatures were performed by a low voltage thermionic arc in a BAI 730M apparatus, while at low temperatures (below 250 °C), the plasma-beam sputtering process in a SPUTRON apparatus was used. We studied the following critical parameters that influence the quality of the coatings and applied the performance tests used in industrial practice: adhesion and scratching coefficient, microhardness, surface topography, oxidation and corrosion resistance. The performance tests were made with the assistance of technicians as well as in 12 Slovenian factories. CrN coatings were deposited at 480 °C for wear and corrosion protection in cold forming and cutting of copper in commutator manufacturing, in forming of aluminium components in automotive production and for surface improvement of moulds (made of H11 steel) in Al-Si die casting under pressure. Deposition temperatures of 180–220 °C, obtained in the SPUTRON apparatus, were required to improve cold forming tools made of alloyed tool steels (e.g. D2 and D3). The lowest obtainable temperature of 140 °C in the SPUTRON gave a CrN coating of high quality for practical use. These coatings were used to protect electrodeposited and electropolished nickel moulds (models) in artificial teeth production. Double TiN+CrN coatings were used as a highly abrasive resistant coating in the production of rotors (in the electromotor industry), and in cold forming and forging in mass manufacturing of screws. The results and performance tests were compared with the available data, mostly published on forming, milling, deep drawing of copper, nickel and titanium and their alloys, and on die casting of aluminium and Al-alloys.

287 citations

Journal ArticleDOI
TL;DR: In this paper, the crystal structure, hardness and oxidation resistance of (Al,Ti,Si)N films were investigated by using transmission electron microscopy with EDS, and the results showed that the films had the same columnar structure as (al,Ti)N but with a smaller column size.
Abstract: Al–Ti–Si–N coatings with several Al/Ti/Si ratios were deposited on WC–Co substrates by the cathodic arc ion plating method. Microstructure and compositions of the local parts of the films were investigated by using transmission electron microscopy with EDS. The films seemed to have the same columnar structure as (Al,Ti)N films but with a smaller column size. The crystal structure, hardness and oxidation resistance were investigated, and Al–Ti–Si–N films with cubic B1 crystal structures had higher hardness than (Al,Ti)N films. Similarly, the Al–Ti–Si–N films displayed greatly improved oxidation resistance at elevated temperatures of up to 1100°C in air. The cutting performances of (Al,Ti,Si)N coated carbide endmills were evaluated and offered significantly better performance in the machining of hardened steels with higher cutting speeds. The wear mechanism and cutting characteristics are discussed along with the film properties.

124 citations

Journal ArticleDOI
TL;DR: The high-temperature oxidation of CrN films which were deposited onto stainless steel substrates using an arc ion plating apparatus was studied at temperatures ranging from 1023 to 1173 K for 0.6 to 480 ks in air as mentioned in this paper.
Abstract: The high-temperature oxidation of CrN films which were deposited onto stainless steel substrates using an arc ion plating apparatus was studied at temperatures ranging from 1023 to 1173 K for 0.6 to 480 ks in air. The oxidation rate obtained from mass gain as a function of time was found to fit well to a parabolic time dependence. Formed oxide layers were analyzed by XRD, SEM, and SAM. An activation energy of the oxidation of CrN was slightly lower than that of the self-diffusion coefficient of Cr ion in Cr2O3. It is concluded that the oxidation of CrN is controlled by the outward diffusion of Cr ions through the Cr2O3 layer formed on each CrN grain.

102 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of the microstructure on the deformation transition is discussed in terms of lattice defect density and the presence of equiaxed grains and microcracks parallel the substrate-coating interface.
Abstract: Cr–N coatings were grown by arc evaporation onto high speed steel substrates. The coatings were each grown using a different negative substrate bias voltage, VS, between 20 and 400 V. X-ray diffraction showed a microstructure containing primarily the NaCl structured CrN phase along with the BCC-Cr and HCP-Cr2N. Auger electron spectroscopy and transmission electron microscopy indicate a substoichiometric (N/Cr=0.85±0.08) composition and dense columnar microstructure, respectively. At VS=400 V, equiaxed grains and microcracks parallel the substrate–coating interface were observed. The fiber textured coatings are in a compressive residual stress state that increases from 2.9 (VS=20 V) to 8.8 GPa (VS=100 V). At higher bias voltages, a decrease of the compressive residual stress is seen, which is discussed in terms of lattice defect annihilation in the collision cascade and lattice defect diffusion during deposition. Nanoindentation showed a maximum hardness at VS=100 V of 29 GPa. The critical loads for cohesive failure in a scratch test decreased monotonically with increasing negative substrate bias. The scratch results suggest a transition in deformation mechanism from plastic deformation to cracking, which occurs at lower applied loads when VS is increased. Similar behavior was also seen in a crater grinding wear test where a shift in wear mechanism from plastic deformation to chipping occurred at VS=200 V. The influence of the microstructure on the deformation transition is discussed in terms of lattice defect density and the presence of equiaxed grains.

102 citations

Journal ArticleDOI
TL;DR: In this article, the crystal structure of (Ti 0.4Al 0.6)N and TiN films was investigated using transmission and scanning electron microscopy, and it was found that (Ti,Al)N coated cutting tools offer significantly better performance characteristics compared to the tools with TiN coatings.
Abstract: (Ti,Al)N coatings with several Ti/Al ratios were deposited on Si and WC–Co substrates by the cathodic arc ion plating method. The crystal structure was found to be cubic B1 type, which is isostructural with the titanium‐based nitrides. Morphology of the (Ti0.4Al0.6)N and TiN films was investigated, using transmission and scanning electron microscopy. The films seemed to have a less columnar structure than expected. The (Ti,Al)N films containing less than 75 mol % AlN had higher hardness than for the pure TiN films. Similarly, (Ti,Al)N coatings displayed superior oxidation resistance at elevated temperatures. Overall, (Ti,Al)N coated cutting tools offer significantly better performance characteristics compared to the tools with TiN coatings.

101 citations