Properties Of CrN Research Articles

Mechanical and Tribological Properties of CrN Coated Inconel X750

Three CrN coatings were deposited on the Inconel X750 through the metal vapor vacuum arc ion implantation and the magnetic filtered cathodic vacuum arc deposition system (MEVVA-FCVA) with the N2 flow rates of 10, 50, and 100 sccm, respectively. The surface morphologies and cross-section morphologies of the CrN coatings were obtained through scanning electron microscopy (SEM) and an optical profilometer. The microstructures of the coatings were characterized through X-ray diffraction (XRD). The hardness and the elastic modulus of the coatings were tested by a nano-hardness tester. The adhesion strength and friction coefficients were investigated through scratch tests and ball-on-disk tests and the wear tracks were tested by the optical profilometer. The experimental results indicate that the CrN coating deposited on the Inconel X750 substrate displays a uniform thickness and a smooth surface. The mechanical properties behaves well as the N2 flow rate varies. The CrN coating significantly reduces the friction coefficient fluctuation and improves the antiadhesion and anti-wear properties of the Inconel X750.

Improvement of Structural, Morphological and Mechanical Properties of CrN<sub>x</sub> Sputtered Thin Films by Vacuum Annealing Process

In this study, CrNx thin films were prepared on 304 stainless steel substrate by DC reactive magnetron sputtering technique. Different N2 gas partial pressure from 10 to 30% was employed in the sputtering process while sputtering power, sputtering pressure and total film thickness were kept constant. In order to improve structural, morphological, and mechanical properties, vacuum annealing process was adopted on the CrNx thin films at the temperature of 400 oC. The standard characterization techniques such as X-ray diffraction, scanning electron microscope, atomic force microscope and hardness (load force of HV0.1) were used to reveal the properties of as-deposited and annealing films. The as-deposited films show two-phase crystal structure of Cr2N and CrN depending on N2 gas partial pressure. After the annealing process, the films effectively enhance the crystal structure and found the phases change from Cr2N to CrN for the film deposited at low N2 partial pressure. The surface roughness of the films was between 5 - 20 nm, and as expected the annealing films shows smoother surface than the as-deposited films. Hardness of the CrNx films is in the range of 7 to 10 GPa. The mechanism of improvement in structural and mechanical properties of annealing films is introduced based on strain relaxation.

The influence of plasma nitriding on microstructure and properties of CrN and CrNiN coatings on Ti6Al4V by magnetron sputtering

In this paper, the CrN and CrNiN coatings were deposited on the non-nitrided and nitrided Ti6Al4V alloys with the method of closed-field unbalanced magnetron sputter ion plating (CFUBMSIP). The influence of plasma nitriding treatment on microstructure, mechanical and tribological properties of Physical Vapor Deposition (PVD) films was evacuated by means of SEM (EDS), XRD, Rockwell-C indentation testing, nanoindentation testing, and ball-on disc tribotesting. With the addition of Ni, the preferred orientation changes to CrN (200) and the grain is refined. The indentation tests indicated that the duplex treated samples exhibited the best combined properties. The nanoindentation testing results showed that the hardness of the coatings increased, the plastic deformation reduced and they had higher H3/E2 values than PVD coatings with the plasma nitriding before PVD treatment due to the increase of substrate's load bear capacity after plasma nitriding process. The friction and wear tests demonstrated that the tribological performance of the PVD coatings improved after plasma nitriding which is attributed to the enhanced the mechanical compatibility between the hard PVD coating and soft substrate and the resistance of CrN coating is better than that of CrNiN coating because of the transfer layer (constituted of TiN and Ti2N) deposited by nitriding.

The Influences of Process Parameters on Properties of CrNx Coatings Deposited by Closed Field Unbalanced Magnetron Sputtering

CrNx coatings were prepared by closed filed unbalanced magnetron sputtering (CFUMS), and the effects of N2 flux ratio and bias voltage on CrN coatings were investigated. Results showed that the phase in coatings was the coexistence of CrN, Cr2N and Cr, and CrN(111) always showed an intensive preferred orientation in both cases, but CrN(200) enhanced with the rise of bias voltage. The hardness of coatings decreased with an increasing N2 flux ratio, while improved with an increasing bias voltage. The grain edges were polished off and the boundaries became blurred when higher bias voltage was applied. All in all, the surface morphologies of CrN coatings became flatter and denser with both increasing N2 content and bias voltage, respectively.

Impact wear and abrasion resistance of CrN, AlCrN and AlTiN PVD coatings

The properties of CrN, AlCrN and AlTiN coatings deposited on cemented carbide substrates by a multiple-arc Physical Vapour Deposition (PVD) technique were evaluated by cyclic impact wear and micro-scale abrasion testing. In the impact wear test, a 6mm diameter tungsten carbide ball was used as the impacting body and the impact frequency (f) was set at 10Hz. In the micro-scale abrasion test, a micro-blasted 25mm diameter hardened steel ball was used as the counterface and a suspension of SiC particles (mean size of 4–5μm) in distilled water as the abrasive slurry. After these wear tests, the wear craters were studied by stylus profilometry, SEM and EDX, to investigate wear behaviour. It is shown that the CrN coating suffered much more severe impact deformation as compared to the two ternary coatings, and exhibited a non-linear increase of the maximum wear depth with increasing number of impact cycles. The impact wear mechanisms of the CrN coating were mainly plastic deformation and micro-delamination. The AlTiN coating exhibited the worst impact wear resistance among the three coatings, mainly due to adhesive wear; in contrast, the AlCrN coating exhibited a lower tendency for the coating to pick-up the ball counterface material, and accordingly demonstrated good impact wear resistance. The AlCrN coating exhibited both the best impact wear performance and the best abrasion resistance amongst the three coatings. The CrN coating exhibited the worst abrasive wear resistance due to its comparatively low hardness. The abrasive wear mechanisms of the CrN coating were a combination of plastic deformation, fine micro-cracking and micro-spallation. The AlTiN coating suffered more severe abrasive wear compared to the AlCrN coating, although both coatings had similar hardnesses.

Effect of N<SUB>2</SUB> Flow on Microstructure and Properties of CrN<SUB>x</SUB> Film Prepared by Unbalanced Magnetron Sputtering on the Surface of Depleted Uranium

金属铀的化学性质十分活泼, 极易发生氧化腐蚀. 为改善基体的抗腐蚀性能, 采用非平衡磁控溅射技术在金属铀表面制备了不同氮含量的CrN x 薄膜. 采用扫描电子显微镜(SEM)、X射线衍射技术(XRD)、X射线光电子能谱(XPS)、动电位极化曲线, 分别研究了薄膜形貌、物相结构、表面元素化学价态及抗腐蚀性能. 结果表明, 当氮流量为10 sccm时薄膜主要为体心立方的α-Cr, 随氮流量的增大, 薄膜转化为六方Cr 2 N和立方CrN结构, 其择优取向由Cr(110)转化为Cr 2 N(111)及CrN(200), 金属态Cr的含量逐渐减少, 氮化态Cr的含量增多, Cr2p3/2的结合能峰位逐渐向高结合能方向移动. CrN x 薄膜呈纤维状结构, 当氮流量增大到30 sccm时, 生成了Cr 2 N的密排结构, 有效改善了薄膜的致密性. 在金属铀表面制备CrNx薄膜后, 自然腐蚀电位增大, 腐蚀电流密度降低, 当氮流量增大到30 sccm时, 薄膜的自然腐蚀电位提高了近550 mV左右, 腐蚀电流密度降低约两个数量级, 有效改善了贫铀表面的抗腐蚀性能.

Characterization and Properties of CrN and CrBN Films

The CrN films and CrBN films were successfully deposited by medium frequency magnetron sputtering in a mixture gas of nitrogen and argon. X-ray diffraction analysis shows that the CrN have preferential orientation of (111), (200) and (222). And the patterns of CrBN films is similar to that of CrN. The CrN films have smooth surfaces with dense and continuous microstructure and the CrBN films have glassy packed structure without columnar grains. The hardness of CrBN films were remarkable improved because of B attending.

Composition, microstructure, and properties of CrN x films deposited using medium frequency magnetron sputtering

CrN x films were deposited on stainless steel and Si (1 1 1) substrates via medium frequency magnetron sputtering in a N 2 + Ar mixed atmosphere. The influence of N 2 content on the deposition rate, composition, microstructure, mechanical and tribological properties of the as-deposited films was investigated by means of the X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), nanoindentation and tribometer testing. It was found that the N atomic concentration increased and the phase transformed from a mixture of Cr 2N + Cr(N) to single-phase Cr 2N, and then Cr 2N + CrN to pure CrN phase with the increase of N 2 content. The Cr 2p 3/2 and N 1s of XPS spectra also confirmed the evolution of phase. Accordingly, all films exhibited a typical columnar structure which lies in the zone T of Thornton Model. The mixed Cr 2N and Cr(N) phases showed low hardness and high friction coefficient. Cr 2N possessed higher hardness than CrN while CrN exhibited lower friction coefficient.

Synthesis and properties of CrN x/amorphous-WC nanocomposites prepared using hybrid arc ion plating and direct current magnetron sputtering

Hybrid deposition method was used to prepare CrN x/amorphous-WC (CrN x/a-WC) films. The effect of the arc ion plating and direct current magnetron sputtering on the changes in microstructure and properties such as hardness and thermal stability were studied. The amorphous WC phase of the CrN x/a-WC films was confirmed by X-ray photoelectron spectroscopy and high resolution transmission electron microscopy. A bi-phase nanocomposite kinetic model and the Koehler's theory were used to explain the growth mechanism of CrN x/a-WC films. A superhard superlattice Cr 2N/a-WC film with hardness up to ~ 48 GPa was abtained. The CrN/a-WC films displayed better resistance to oxidation than pure CrN and CrN-based films. As such, CrN x/a-WC nanocomposite films are very promising for high-speed drying machines and other high-temperature applications.

The Microstructure and Properties of CrN<sub>x</sub> Films Synthesized by Unbalanced Magnetron Sputtering

CrNx film was widely used in mechanical engineering field because of its excellent anti-wear and corrosion resistance properties. While most of research was focused on mechanical properties, little attention had been paid to the corrosion resistance and residual stress of CrNx film . In this paper, CrNx films were deposited on silicon wafer (100) and iron substrate by unbalanced magnetron sputtering system (UBMS) at different N2 flow. Then the structure, thickness, residual stress, micro-hardness, wear-resistance and anti-corrosion properties of CrNx films were investigated. The results showed that the phase composition of CrNx films transformed from Cr, single phase Cr2N, Cr2N and CrN coexist to single CrN with the N2 flow rate increasing. The CrNx films composed with Cr2N phase, which deposited at 6 sccm N2 flow, had the highest microhardness and had higher compressive residual stress. Whereas the CrNx films with CrN and Cr2N phase coexist had the best wear and corrosion resistance.

Comparative Studies on Microstructure and Mechanical Properties of CrN, Cr-Mo-N and Cr-Si-N Coatings

CrN-based multi-component coatings were deposited by a hybrid coating system combining the arc ion plating (AIP) and sputtering technique. In this work, comparative studies on microstructure and mechanical properties of microhardness and wear behavior among CrN, Cr-Mo- N, Cr-Si-N coatings were systematically conducted. Adding Mo and Si atoms into CrN coatings had important effects on microstructural change and mechanical properties of CrN coatings. The maximum hardness values of Cr-Mo-N and Cr-Si-N coatings were the same value of 34GPa, These values were much enhanced compared with 18GPa of CrN coating. The average friction coefficient of CrN-based coatings decreased to 0.37 and 0.2 with the incorporation of Mo and Si content

Engineered Nanocrystallites for Enhanced Performance of Ceramic Coatings by Ion Beam Assisted Deposition

AbstractTypical high-temperature thin-film deposition techniques are not suitable for certain substrates such as polymers and thermally-sensitive steels. In this work, ion beam assisted deposition (IBAD) was used to deposit ceramic and metallic films at temperatures below 150°C with nanocrystalline (< 100Å diameter) grain size. Nanoindentation studies of these films have shown hardnesses 50 to 100% greater than larger-grained films and, in some cases, fracture toughness approaching that of Si3N4.By combining chromium evaporation with nitrogen beam bombardment, hard, adherent CrN films without any porosity have been produced at low temperatures with a N/Cr arrival ratio of about 1. The grain size is typically smaller than 100Å and hardness is typically higher than 25 GPa. For a N/Cr arrival ratio slightly less than 1, we observed possible grain boundary porosity. However, even with porosity, hardness is typically 20 to 24 GPa for grain sizes smaller than 100Å. For a N/Cr arrival ratio of 1/4 we deposited elemental Cr with a grain size of 300 to 500Å and a hardness greater than that of silicon (12 GPa). Using Ar ions and a N backfill, we produced elemental Cr containing a mixture of coarse (120 to 150Å) and fine (25 to 30Å) grains. For high-temperature deposition of CrN, the grain size increases (200 to 600Å) with a noticeable decrease in hardness. Mechanical properties of CrN are greatly influenced by impurities, as well as by surface conditioning of the substrate.TiN films having gold color and grain sizes from 50 to 1000Å have been produced at low temperatures. Nanoindentation measurements of hardness and fracture toughness indicate that impurity-free TiN (with grains smaller than 100Å) has a hardness higher than 25 GPa and a fracture toughness close to that of Si3N4, but with higher wear resistance. Mechanical properties of our TiN films are greatly influenced by impurities, particularly oxygen, although it does not influence the gold color of TiN.

Properties of Crn and (Ti, Al)N Coatings Produced by High Rate Sputter Deposition

CrNand (Ti, Al) N coatings have been deposited by high rate sputter deposition. CrN is one of the most uncritical coatings to produce, neither microhardness nor sputtering stability being influenced by sputtering conditions. Depending upon the nitrogen partial pressure during deposition and the aluminium content, (Ti, Al) N coatings with maximum microhardness values of 2200–3000 HV0.01 can be obtained. Such coatings have superior oxidation and wear resistance compared to normal sputtered TiN coatings.