Reactive Cathodic Arc Evaporation Research Articles

The influence of corrosive medium on the selected tribological properties of ZrSi-based nitride and oxynitride deposited on 316L stainless steel

Targeting to restore the function of load-bearing joints which are subjected to high levels of friction and wear during the normal activity, the aim of the current study was to assess the extent of the role played by the corrosive environment on the underlaying tribological mechanism. In this study we deposited by reactive cathodic arc evaporation technique ∼ 1 μm thick, stoichiometric ZrSi-based nitrides and oxynitrides coatings, either as monolayer or double-layer structure on 316L steel substrates. Tribological tests were conducted in dry and two commonly used corrosive environments: Ringer and 0.9 % NaCl solutions. We demonstrate that the ZrSiN and ZrSi(N,O) coatings improved the wear performance of 316L stainless steel in biological environments, reaching even ∼ 94 % improvement as compared with the bare substrate for the ZrSi(N,O) coating.

Corrosion Improvement of 304L Stainless Steel by ZrSiN and ZrSi(N,O) Mono- and Double-Layers Prepared by Reactive Cathodic Arc Evaporation

Zr-based nitrides and oxynitrides were deposited by reactive cathodic arc evaporation in monolayer and double-layer structures with the aim of increasing the corrosion protection of 304L stainless steel (SS) in a biomedical aggressive environment. All coatings had a total thickness of 1.2 µm. Compared to the bare substrate, the surface roughness of the coated samples was higher, the presence of microdroplets being revealed by scanning electron micrography (SEM). The X-ray diffraction investigation of the ZrN phases revealed that the peaks shifted towards lower Bragg angles and the lattice constants increased as a result of Si and O2 inclusion in ZrN lattice, and of the ion bombardment characteristic of the cathodic arc method, augmented by the applied bias substrate. SS/ZrSiN/ZrSi(N,O) showed the best corrosion performance in an acidic environment (0.9% NaCl and 6% H2O2; pH = 4), which was ascribed to the blocking effect of the interfaces, which acted as a corrosion barrier for the electrolyte ingress. Moreover, the aforementioned bilayer had the highest amount of Si and O in the composition of the top layer, forming a stable passive layer with beneficial effects on corrosion protection.

Insights into the role of the layer architecture of Cr–Ti–N based coatings in long-term high temperature oxidation experiments in steam atmosphere

Knowledge on hard coatings has been applied in the energy field extending their use as protecting coatings of steam power generation plants components. The role of the layer architecture of Cr–Ti–N based coatings deposited by reactive cathodic arc evaporation on P92 steel substrates was studied with the focus on their oxidation resistance at 650 °C in 100% steam atmosphere up to 2000 h. Characterization of the coatings was performed by gravimetry, scanning electron microscopy, electron probe microanalysis, glow discharge optical emission spectroscopy, X-ray diffraction, thermodynamic simulations using the CALPHAD method, Rockwell C indentation and nanoindentation. The layered arrangement improves the oxidation resistance of TiN under the working conditions of steam power plants, as well as the mechanical properties of CrN. The produced architectures performance under the described working conditions boosts the understanding of the processes taking place at high temperature, making possible the design of optimal coatings combining the best behavior of both nitrides for each specific application, reaching a corrosion protection at high temperature in water vapor comparable to that of CrN and a hardness and Young's modulus as high as those of TiN.

Impact wear-resistance of Ti-Cr-B-N coatings produced by pulsed CAE of ceramic target

Ti–Cr–B–N coatings were successfully deposited using reactive pulsed cathodic arc evaporation (CAE) of ceramic TiCrB target. The influence of the substrate negative bias voltage on the coating impact wear resistance and mechanical properties has been studied. Structural investigations have been carried out using X-ray diffraction analysis, transmission and scanning electron microscopy, glow-discharge optical-emission spectroscopy, and optical profilometry. The coating properties have been estimated by impact tests, scratch-test, and nanoindentation. The obtained results show that the coatings consist of Ti(Cr)N fcc phase with crystallites 1–2 nm in size and amorphous BNx tissure. The coatings obtained at Ubias=-250 V demonstrated highest hardness of 24 GPa, whereas samples deposited at Ubias=-500V exhibited minimal wear rate (worn area of 12 μm2) in impact conditions. Coatings obtained by pulsed CAE with intensive ion-bombardment possess high adhesion strength higher than 120 N.

Substrate rotation-induced chemical modulation in Ti-Al-O-N coatings synthesized by cathodic arc in an industrial deposition plant

Reactive cathodic arc evaporation of Ti-Al-O-N was carried out in an industrial deposition system with two-fold substrate rotation. The structural and compositional evolution of the coatings was st ...

Improvement of the tribological performance in corrosive environment of CoCr alloy by TiSiON coatings

TiSiON thin films for load bearing applications were prepared by reactive cathodic arc evaporation at different substrate bias voltages. The influence of deposition parameters on the tribological performance of coated CoCr samples was investigated. The tribological performance of uncoated and coated CoCr alloy surfaces was investigated in 0.9% NaCl solution. The friction coefficient of the TiSiON in corrosive environment exhibited values ranging from 0.1 to 0.3. Combined adhesive and oxidative wear mechanism was found. All of the coatings demonstrated a better tribological performance when compared with uncoated CoCr substrate. Of the investigated coatings, TiSiON deposited at −200V bias voltages exhibited the best tribological performance in 0.9% NaCl, both in friction coefficient (0.1) and wear rate (6.29×10−6mm3/Nm).

High pressure and high temperature behaviour of TiAlN coatings deposited on c-BN based substrates

TiAlN and TiAlN-based coatings that are used of relevance as protection of cutting tool inserts used in metal machining have been studied. All coatings were deposited by reactive cathodic arc evaporation using industrial scale deposition systems. The metal content of the coatings was varied by using different combinations of compound cathodes. The as-deposited coatings were temperature annealed at ambient pressure and in some cases also at high pressure. The resulting microstructure was first evaluated through a combination of x-ray diffraction and transmission electron microscopy. In addition, mechanical properties such as hardness by nanoindentation were also reported.TiAlN coatings with two different compositions were deposited on polycrystalline boron nitride substrates and then high pressure high temperature treated in a BELT press at constant 5.35 GPa and at 1050 and 1300 °C for different times.For high pressure high temperature treated TiAlN it has been shown that the decomposition is slower at higher pressure compared to ambeint pressure and that no chemical interaction takes place between TiAlN and polycrystalline cubic boron nitride during the experiments. It is concluded that this film has the potential to protect a polycrystalline cubic boron nitride substrate during metal machining due to a high chemical integrity.TiZrAlN coatings with different predicted driving forces for spinodal decomposition were furthermore annealed at different temperatures. For this material system it has been shown that for Zr-poor compositions the tendency for phase separation between ZrN and AlN is strong at elevated temperatures and that after spinodal decomposition stable TiZrN is formed.

Structural and mechanical properties of corundum and cubic (AlxCr1−x)2+yO3−y coatings grown by reactive cathodic arc evaporation in as-deposited and annealed states

Coatings of (AlxCr1−x)2+yO3−y with 0.51⩽x⩽0.84 and 0.1⩽y⩽0.5 were deposited on hard cemented carbide substrates in an industrial cathodic arc evaporation system from powder-metallurgy-prepared Cr/Al targets in pure O2 and O2+N2 atmospheres. The substrate temperature and bias in all the deposition runs were 575°C and −120V, respectively. The composition of the coatings measured by energy dispersive X-ray spectroscopy and elastic recoil detection analysis differed from that of the facing targets by up to 11%. Microstructure analyses performed by symmetrical X-ray diffraction and transmission electron microscopy showed that corundum, cubic or mixed-phase coatings formed, depending on the Cr/Al ratio of the coatings and O2 flow per active target during deposition. The corundum phase was promoted by high Cr content and high O2 flow per target, while the cubic phase was observed mostly for high Al content and low O2 flow per active target. In-situ annealing of the cubic coatings resulted in phase transformation from cubic to corundum, completed in the temperature range of 900–1100°C, while corundum coatings retained their structure in the same range of annealing temperatures. Nanoindentation hardness of the coatings with Cr/Al ratio <0.4 was 26–28GPa, regardless of the structure. Increasing the Cr content of the coatings resulted in increased hardness of 28–30GPa for corundum coatings. Wear resistance testing in a turning operation showed that coatings of Al–Cr–O have improved resistance to crater wear at the cost of flank wear compared with TiAlN coatings.

Effects of Ti alloying of AlCrN coatings on thermal stability and oxidation resistance

Quaternary cubic (TixCr1−xAl~0.60)1N1 coatings with 0<x<0.33 have been grown using reactive cathodic arc evaporation. When adding Ti the hardness was retained after annealing up to 1100°C which is a dramatic improvement compared to CrAlN coatings. The coatings showed an age hardening process caused by spinodal decomposition into coherent TiCr- and Al-rich cubic TiCrAlN domains and the formation of hexagonal AlN precipitates and cubic TiCrN domains in the vicinity of the grain boundaries. The improved hardness was attributed to the stabilization of the cubic structure suppressing the formation and growth of hexagonal AlN. Furthermore, the presence of Ti atoms generated incoherent nanometer-sized crystallites within the hexagonal AlN precipitates disrupting the hexagonal lattice during the coarsening process.The addition of Ti promoted the formation of a TiO2 layer over Al2O3 resulting in a lower oxidation resistance. However, by tuning the composition it is possible to design coatings to have both good oxidation resistance and good high temperature mechanical stability.

Microstructure and thermal stability of corundum-type (Al0.5Cr0.5)2O3 solid solution coatings grown by cathodic arc evaporation

Corundum-type (AlxCr1−x)2O3 coatings were grown by reactive cathodic arc evaporation in an oxygen atmosphere using AlCr targets with an Al/Cr atomic ratio of 1. Since the (AlxCr1−x)2O3 solid solution shows a miscibility gap below 1300°C, where spinodal decomposition is predicted, the microstructural changes upon annealing were investigated by a combination of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry. The as-deposited coating consists primarily of the corundum-type (AlxCr1−x)2O3 solid solution, with smaller fractions of cubic (AlxCr1−x)2O3. An additional Al-rich amorphous phase and a Cr-rich crystalline phase stem from the droplets incorporated. The corundum-type (AlxCr1−x)2O3 solid solution is still present after vacuum annealing at 1050°C for 2h, whereas the cubic (AlxCr1−x)2O3 phase has transformed to corundum-type (AlxCr1−x)2O3. Cr and Cr2O3 have been detected in the annealed coating, the latter most probably originating from the partial oxidation of Cr-rich droplets. Upon crystallization of the amorphous phase fractions present, γ-Al2O3 is formed, which then transforms into α-Al2O3. No evidence for decomposition of the corundum-type (AlxCr1−x)2O3 solid solution could be found within the temperature range up to 1400°C.

Microstructure evolution of Ti3SiC2 compound cathodes during reactive cathodic arc evaporation

The microstructure evolution and compositional variation of Ti3SiC2 cathode surfaces during reactive cathodic arc evaporation are presented for different process conditions. The results show that phase decomposition takes place in the near-surface region, resulting in a 5–50 μm thick converted layer that is affected by the presence of nitrogen in the deposition chamber. This layer consists of two different sublayers, i.e., 1–20 μm thick top layer with a melted and resolidified microstructure, followed by a 4–30 μm thick transition layer with a decomposed microstructure. The converted layer contains a polycrystalline TiCx phase and trace quantities of Si-rich domains with Ti5Si3(C) at their interface. The arc discharge causes Si redistribution in the two regions of the layer, whose Si/(Ti+Si) ratio is higher in the top region and lower in the transition region compared to the virgin material.

Correlation between target surface and layer nucleation in the synthesis of Al–Cr–O coatings deposited by reactive cathodic arc evaporation

The deposition parameters of reactive cathodic arc are correlated with processes at the surface of the composite Al–Cr targets and the nucleation and phase formation of the synthesized Al–Cr–O layers. The oxygen pressure and the pulsed operation of the arc current influence the formation of intermetallic phases and solid solutions at the target surface. The nucleation of the ternary oxide coatings at the substrate site appears to be, to some extent, controllable by the intermetallics or solid solutions formed at the target surface. A specific nucleation process at the substrate site can therefore be induced by the free choice of target composition in combination with the oxygen pressure and a pulsed arc operation. It also allows the control over the oxide island growth at the target surface which occurs occasionally at higher oxygen pressure. This hypothesis is supported by the X-ray diffraction analysis of the layers as well as of the target surface, and the layer analysis by cross-sectional scanning electron microscopy and Rutherford backscattering spectroscopy.

Microstructure evolution and age hardening in (Ti,Si)(C,N) thin films deposited by cathodic arc evaporation

Ti 1 − x Si x C y N 1 − y films have been deposited by reactive cathodic arc evaporation onto cemented carbide substrates. The films were characterized by X-ray diffraction, elastic recoil detection analysis, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electron-energy loss spectroscopy and nanoindentation. Reactive arc evaporation in a mixed CH 4 and N 2 gas gave films with 0 ≤ x ≤ 0.13 and 0 ≤ y ≤ 0.27. All films had the NaCl-structure with a dense columnar microstructure, containing a featherlike pattern of nanocrystalline grains for high Si and C contents. The film hardness was 32–40 GPa. Films with x > 0 and y > 0 exhibited age-hardening up to 35–44 GPa when isothermally annealed up to 900 °C. The temperature threshold for over-ageing was decreased to 700 °C with increasing C and Si content, due to migration of Co, W and Cr from the substrate to the film, and loss of Si. The diffusion pathway was tied to grain boundaries provided by the featherlike substructure.

Characterization of worn Ti–Si cathodes used for reactive cathodic arc evaporation

The microstructural evolution of Ti1−xSix cathode surfaces (x=0,0.1,0.2) used in reactive cathodic arc evaporation has been investigated by analytical electron microscopy and x-ray diffractometry. The results show that the reactive arc operated in N2 atmosphere induces a 2–12 μm thick N-containing converted layer consisting of nanosized grains in the two-phase Ti and Ti5Si3 cathode surface. The formation mechanism of this layer is proposed to be surface nitriding and redeposition of macroparticles formed during the deposition process. The surface roughness of the worn Ti1−xSix cathodes increases with increasing Si content, up to 20 at. %, due to preferential erosion of Ti5Si3.

Approaches to influence the microstructure and the properties of Al–Cr–O layers synthesized by cathodic arc evaporation

Al–Cr–O layers were synthesized by reactive cathodic arc evaporation utilizing DC as well as pulsed operation of the arc sources. The observed increase of the substrate ion current in the pulsed mode is attributed to the increased ionization of the oxygen reactive gas. The influence of the substrate ion current and the oxygen flow on the microstructure of the layers has been investigated. A strong influence of the oxygen gas flow on morphology and crystal structure has been observed. The increased substrate ion current in the pulsed mode has seemingly no influence on layer morphology at low bias voltages, but influences the nucleation behavior of the layer. The appearance of a multi-layer structure in the synthesized layers utilizing a single composite target has been ascribed to partial ion splitting of the target constituents in the curvilinear arc discharge.

Wear-resistant Ti–B–N nanocomposite coatings synthesized by reactive cathodic arc evaporation

Abstract Wear-resistant Ti–B–N coatings have been synthesized by reactive arc evaporation of Ti–TiB 2 compound cathodes in a commercial Oerlikon Balzers Rapid Coating System. Owing to the strong non-equilibrium conditions of the deposition method, a TiN–TiB x phase mixture is observed at low N 2 partial pressures, as determined by elastic recoil detection analysis, X-ray diffraction, X-ray spectroscopy, transmission electron microscopy and selected area electron diffraction. The indicated formation of a metastable solid solution of B in face-centered cubic TiN gives rise to a maximum in hardness (>40 GPa) and wear resistance on the expense of increased compressive stresses. A further saturation of the nitrogen content results in the formation of a TiN–BN nanocomposite, where the BN phase fraction was tailored by the target composition (Ti/B ratio of 5/3 and 5/1). However, the amorphous nature of the BN phase does not support self-lubricious properties, showing friction coefficients of 0.7 ± 0.1 against alumina. The effect of an increased bias voltage on structure and morphology was investigated from −20 to −140 V and the thermal stability assessed in Ar and air by simultaneous thermal analysis up to 1400 °C.

Deposition and characterization of TiBCN films by cathodic arc plasma evaporation

TiBCN thin films were deposited on Si(100) substrate by reactive cathodic arc evaporation from a graphite/boron-containing composite target and Ti target in an N 2 atmosphere. Characteristics and microstructures of the films were investigated, deposited under different target currents. Raman spectroscopy and high resolution X-ray photoelectron spectroscopy (HRXPS) were employed to investigate the spectrum and bonding states of films. The film microstructures were evaluated by using an atomic force microscope (AFM), a field emission scanning electron microscopy (FEGSEM), a glancing angle X-ray diffractometry (GAXRD) and a high-resolution transmission electron microscopy (HRTEM). Results demonstrated that the TiBCN films were synthesized successfully and adhered well to the silicon substrate. The Raman spectra showed that wavenumbers ranging from 900 to 1800 cm − 1 consisted of D and G bands, similar to that of cathodic arc plasma deposited DLC. Raman spectra proved that the intensity of D and G bands decreased by increasing Ti target currents. HRTEM results established that TiBCN films revealed an amorphous structure while the Ti target current was low. As the Ti target current increased, the TiBCN films revealed a nanocomposite structure, an amorphous matrix consisting of nano scale Ti(C,N) and TiB crystalline, which were comparable to GAXRD, Raman and HRXPS results. The HRXPS spectra of B1s, C1s, N1s and Ti2p in the TiBCN films reveal much broader peaks; this indicated that there is more than one category of bonding state surrounding each of Ti, B, C and N atoms. Morphology, characteristics and film concentration as a function of deposition parameters were also investigated in this study.

Structure–property relations of arc-evaporated Al–Cr–Si–N coatings

The addition of silicon to the widely used aluminum-containing transition metal nitrides is promising for the synthesis of hard and thermally stable films with good oxidation resistance. For that reason, Al–Cr–Si–N coatings were deposited by reactive cathodic arc-evaporation under industrial conditions from Al 70Cr 30 − x Si x ( x = 0, 1, 2, 5 at.%) targets at substrate bias voltages ranging from − 40 V to − 150 V. The structure of the well adherent coatings was investigated by X-ray diffraction and Raman spectroscopy, which indicated at higher Al/Cr ratio > 1.9 an increased tendency of the metastable face-centered cubic solid solution of AlN in CrN to separate into a cubic–hexagonal phase mixture. At higher bias voltages, this effect is gradually inverted and the single cubic phase can be retained. X-ray photoelectron spectroscopy revealed dominant Si–N bonds suggesting either a substitutional solid solution or a separate Si–N phase. Mechanical properties, i.e. hardness and elastic modulus, measured by indentation together with stress evolution demonstrate the beneficial effect of the conservation of the metastable cubic phase.

Nanocomposite AlTiNCO Coatings Deposited by Reactive Cathodic Arc Evaporation

AlTiNCO coatings were deposited by the reactive cathodic arc evaporation. In addition, TiNC coatings with different carbon contents were deposited to compare the influence of carbon addition on the oxidation depth between TiNC and AlTiNCO coatings. Variations in microstructure, morphology, and chemical composition were correlated with mechanical properties. High-resolution transmission electron microscopy revealed that nanocrystalline phases are present. Higher carbon contents lead to the precipitation of free carbon resulting in a nanocomposite structure of AlTiNCO/C. Raman spectroscopy of the nanocomposite structure showed spectra typical of nanocrystalline carbon. It was shown that the additional carbon had a positive influence on the cutting performance in dry cutting.

Deposition of zirconium oxynitride films by reactive cathodic arc evaporation and investigation of physical properties

The area of metal oxynitrides is poorly explored, and understanding of the fundamental mechanism that explains structural, mechanical, electrical, and optical properties is still insufficient. Therefore, the purpose of the present investigation is to analyze structural, electrical, and optical properties of ZrNxOy films deposited by reactive cathodic arc evaporation.Depending on the oxygen flow, cubic ZrN:O, monoclinic ZrO2:N, and tetragonal ZrO2:N phases films were prepared. The sheet resistance and the optical transmittance very much depend on the oxygen flow. Optical transparent ZrNxOy films with transmittance of 86% at 650 nm, the sheet resistance 1.1·103 Ω/sq, and the figure of merit 2·10−4 Ω−1 are deposited with the 60 sccm oxygen flow.