Papers by Keyword: Cathodic Arc Deposition

Abstract: The influence of Al/Ti and Al/Cr ratios on the structural, mechanical and tribological properties of AlTiSiN and AlCrSiN coatings, deposited by the cathodic arc evaporation PVD method at a temperature of 400°C, was investigated. The remains of the original AlSiN hexagonal phase were observed in the obtained coatings as well as the crystallites of cubic TiN and CrN, respectively. XPS analysis assumes the presence of a substoichiometric SiN. The addition of 11 at.% Ti or 13 at.% Cr in AlSiN led to an increase in both the coating’s resistance to plastic deformation and the plasticity index. The addition of 13 at.% and 24 at.% Cr to the AlSiN coating structure resulted in a decrease in the average coefficient of friction with 18% and 36% against a counterpart of Al₂O₃, respectively, and with 36% for both concentration against steel ball counterpart. The addition of Ti have no influence on the values of the coefficient of friction at using ceramic counterpart, while at steel counterpart decreased it up to 30%. Both element change the abrasion effect of the coating.Keywords: AlCrSiN; AlTiSiN; Cathodic Arc Deposition; Tribological Behaviour; Abrasion Resistance; Nanoindentation

Abstract: TiCN thin coatings with various different carbon contents were deposited using cathode arc evaporation of pure titanium in a mixture of N₂ and C₂H₂ gasses at a constant pressure of 1.5 Pa. The analyses show a transition from a stoichiometric to a non-stoichiometric coating structure with an increasing C₂H₂ content. Moreover, the increase in the acetylene in the gas mixture leads to a decrease in the crystal phase from pure polycrystalline to pure amorphous. Nanohardness changes from 30.4 to 4.4 GPa and the cohesive failure of the coatings is in the range of 61 - 72 N. The tribology is estimated by the Ball-on-Disc method and an Si₃N₄ ball as the counterpart. The measured coefficient of friction is in the range of 0.2 - 0.56.

Abstract: This paper is a continuation of our previous work. The article presents an investigation of the influence of coating deposition parameters, in particular a variation with 50% of both cathodic arc current and bias voltage, on the mechanical and tribological properties of TiCN coatings deposited by the cathodic arc evaporation of metals at a constant gas ratio. The thicknesses of the coatings are measured by the Calotest method using a 30-mm hard steel ball. The determined values are in the range of 734 – 1534 nm. Surface morphology and chemical composition are estimated by a Scanning Electron Microscope (SEM) and an Energy Dispersive Spectrometer (EDS) of SEM. The determined values of nanohardness are in the range of 10 - 23 GPa and adhesion values are in the range of 28 - 70 N. Tribology of the TiCN coatings is investigated with three different load forces (3N, 5N and 8N) by the CETR UMI Multi-Specimen Test System from Bruker with an Si3N4 ball counter-body. The friction coefficient is measured in the range of 0.19 - 0.23. Coating wear and wear of the counter-body are calculated, according to the standard EN1071-13:2010, wherein the values of the latter are in the range of (2.5 - 30) x 10-6 mm3.

Abstract: In this research, the possibility of applying multilayer multielement super hard coatings by Cathodic Arc is investigated. More precisely the structure of the coating consisting of quaternary CrAlSiN and ternary AlSiN layers is examined by electron microscopy, X-ray diffraction and X-ray photoelectron microscopy analytical methods. The as-deposited samples were found to have distinguishable layers. The CrAlSiN layer is characterized by an extra sequence of repeated nanolayers. The AlSiN layer consisted of nanosized grains having a preferential orientation. Finally the surface layer was found to contain a solid solution of CrxAl1-xN, while Si3N4was identified only by XPS most probably due to its amorphous structure.

Abstract: Aluminum chromium nitride (AlCrN) coatings and aluminum chromium oxynitride (AlCrON) coatings were successfully fabricated through cathodic arc deposition with pulsed bias. The results indicated that both AlCrN and AlCrON coatings had a lower coefficient of friction against AISI 52100 bearing ball under dry conditions than CrN coating. The hardness of the AlCrN coating was in the range of 30 GPa, two times higher than that of the AlCrON coating. Thermogravimetric and differential scanning calorimetry analyzer (TGA/DSC) confirmed the best thermal stability of the AlCrON coating during the test.

Abstract: The present study addresses the influence of the gradient microstructure of nanocrystalline TiAlSiN coatings on their tribological behaviour. Cathodic arc deposition was applied to elaborate such coatings, with a total thickness of 3.5 μm, onto stainless steel substrates. Their microstructure has been characterised via Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS) and has been reported in detail previously. Since the main application of TiN-based coatings is the enhancement of the anti-wear resistance of metallic substrates, this work is focused on the tribological performance of gradient TiAlSiN coatings under dry sliding conditions. For this purpose, tests were carried out in a ball-on-disc apparatus, using an alumina ball as counterbody. The influence of the sliding velocity on the evolution of the friction coefficient and the wear lifetime of the gradient coatings has been evaluated in comparison to those of TiN coatings of the same thickness, tested under the same experimental conditions. It was found that the gradient microstructure results in an increase of the coatings’ mean lifetime by an average factor of three.

Abstract: Bipolar plate with multiple functions is one of the essential components of the PEMFC (Proton Exchange Membrane Fuel Cells) stacks. Recently, metallic bipolar plates, particularly different grades of stainless steels, have been increasingly considered due to relatively low cost, good corrosion resistance, sufficient stiffness and excellent flexibility in thin forms, and easy manufacturability [1-3]. However, the major concerns with the use of stainless steel alloys as bipolar plates are their corrosion resistance and interfacial electrical resistance under long operation conditions. Development of advanced ternary nitride coatings such as chromium silicon nitride (CrSiN) has attracted significant industrial interest in recent years [4-11]. Si addition of CrN to form CrSiN films were prepared by cathode arc ion deposition technique and magnetron sputter technique, in order to improve the characterizations of the coatings from structure to corrosion behaviors. It is reported that with the additional element of Si, the hardness and corrosion resistance of the CrSiN coatings can be greatly improved compared to that of the CrN coating. A direct link between the microstructure and mechanical properties of CrSiN coatings with varying Si contents was established [8]. With increasing Si content, the structure of CrSiN coating exhibited the transformation from a columnar-grained structure to a nanocomposite structure, consisting of CrN nanocrystallites embedded in an amorphous matrix. A maximum hardness of 26.6 GPa was found for CrSiN coating with Si content of about 6.7 at.%, while that of pure CrN was 19.4 GPa [6]. Up to now, the CrSiN is yet thoroughly investigated.

Abstract: A study of the structural and mechanical properties of nanocrystalline TiAlSiN gradient coatings deposited by cathodic arc deposition techniques at 500 °C and post-annealed at 525 °C is presented. Analysis of the coatings, chemical composition and microstructure revealed that the coatings have a structure based on (Ti, Al)N nanocrystals with an average size of 10 nm embedded in an amorphous Si₃N₄ phase. The study of the mechanical properties showed that post-annealing causes improvement and increase of the coatings hardness. A maximum hardness of 48 GPa and elastic modulus of 560 GPa were measured. Also, excellent adhesion to the WC-Co substrate was observed in the post-annealed coatings.

Abstract: (Ti,Al)N coatings possess superior hardness, good thermal and chemical stability. To further study the oxidation resistance, the arc-deposited AlTiN bulk material was collected from the substrate shutter of a commercial coating system deposited for over 100 batches. The thermal behaviour of the materials was studied by TGA/DSC with different annealing temperature or different atmospheres. The results show that AlTiN bulk material annealed in nitrogen exhibits the denser structure and thermal stability up to 1000°C. The oxidation resistance of the AlTiN can reach to 800°C. Annealed at 600 ~ 700°C proceed the recrystallization process which denser the structure. New phase of TiO₂ is formed by incorporate oxygen in exchange of nitrogen. nanoscaled 1D wire formation occurred at the 1000°C for 3 hours in air.

Abstract: This study utilized the reaction of O₂/N₂ gases and Al_0.67Ti_0.33/Cr (99.9%) dual targets to synthesize (Ti,Al)ON/CrON multilayered coatings on AISI M2 steel by cathodic arc deposition system. Thermal stability and corrosion resistance of the multilayered coatings for aluminum die casting applications, along with coating structure were investigated. The results showed that the structure of multilayered coatings was a B1 NaCl type. The formation of oxide phases by introducing oxygen to react with Al, Cr, and Ti elements was confirmed by XPS. The thermal stability of oxygen-doped AlTiN/CrN coatings was higher than that of one without oxygen. After the immersion tests in Al-alloy melt, the oxygen-doped AlTiN/CrN coatings deposited at the O₂/N₂ ratio value of 0.3 had the best improvement on the corrosion resistance among all the coated specimens.