TiSiCN Coatings Research Articles

BRIEF OVERVIEW OF METHODS FOR PRODUCING TiSiCN COATINGS AND THE METHOD OF REACTIVE PLASMA SPRAYING

Modern materials science sets itself the task of developing new materials with multifunctional coatings. Materials with such coatings are widely used in various fields of technology: construction and energy, microelectronics, aviation and others. The main reason for the emergence and development of technology for applying multifunctional protective coatings is the desire to increase the durability of parts and assemblies of various machine mechanisms. Wear-resistant hard coatings based on transition metal nitrides and carbonitrides are widely used to extend the life of forging and extrusion dies and high-speed machining tools. Over the past two decades, the widespread use of these coatings has stimulated and supported the development of new processes and materials in an attempt to further improve their properties. Among these coatings, the higher hardness, excellent oxidation resistance and high thermal stability of coatings such as TiSiN and TiSiCN make them the most promising candidates for demanding tribological applications. In addition, TiSiCN coating is a promising material used in marine environments due to its excellent anti-wear and corrosion resistance, as well as high hardness and low friction coefficient. These combinations of properties make TiSiCN coatings potential candidates for protective layers in the automotive and petroleum industries.The article briefly examines the possibilities of producing TiSiCN coatings using different deposition methods to control the properties of the resulting films and the features of the reactive plasma spraying method. The work describes the most common methods and technologies for producing carbonitride coatings currently used. The latest developments and current trends in the field of plasma spray coating technologies are reviewed, taking into account important innovations for industrial coatings. New conclusions that were obtained as a result of fundamental and applied research in physics or chemistry are based on them. The article provides a comparative review of the characteristics of obtaining wear-resistant TiSiCN coatings and the features of using reactive plasma spraying to obtain wear-resistant coatings. Based on an analysis of the literature, it can be argued that the further development of reactive plasma technology is associated with the development of a new resource-saving method for the formation of composite coatings with increased corrosion and tribological characteristics, which corresponds to the development trends of world science.

Structure, mechanical properties and tribocorrosion behaviours of superhard TiSiCN nanocomposite coatings

Superhard coatings are no longer very difficult to obtain, but the direct observation and prediction of their failure are still a challenge. 3D tomography of the microcracks in coating failure offers lots of new information on the geometric shape, size, and spatial structure relationship of microcracks which was not available up to now. Hence, in this work, cross-scale visualization analysis of the microcrack network in superhard yet toughness TiSiCN coatings around indentations was achieved through advanced 3D tomography combined with HRTEM characterization. TiSiCN nanocomposite coatings were deposited by high-power pulsed magnetron sputtering. Superhard TiSiCN coatings exhibit a simultaneous superhardness of 48 ± 6.99 GPa and favorable toughness due to fully dense microstructure and smooth surface morphology. Due to the excellent crack initiation resistance and super-high hardness, superhard TiSiCN coatings show enhanced tribocorrosion performance in 3.5 wt% NaCl aqueous solution, with a low coefficient of friction of 0.11 and low specific wear rates of 3.23 × 10−6 mm−3N−1m−1.

Thermodynamic reassessments of the Ti–Si–C/Ti–Si–N systems and thermodynamic calculations of CVD TiSiCN hard-coating based on the Ti–Si–C–N quaternary system

The Ti–Si–C and Ti–Si–N systems were thermodynamically reassessed by using the CALculation of PHAse Diagram (CALPHAD) approach. A more suitable Gibbs energies expression of Ti3SiC2 was obtained to fit better with heat capacity data in the Ti–Si–C system. The thermodynamic parameters of the Ti–Si–N system were adjusted based on the revised Ti–Si system. A self-consistent thermodynamic database of the quaternary Ti–Si–C–N system was established. The calculated thermodynamic data and phase diagrams agree well with the experimental data. The CVD (Chemical Vapor Deposition) process for TiSiCN coatings was simulated using the newly evaluated thermodynamic parameters of the Ti–Si–C–N system. A good agreement between the predicted coating composition and the experimental ones was achieved, verifying the reliability of the thermodynamic database obtained in the present work.

Plasma Enhanced High-Rate Deposition of Advanced Film Materials by Metal Reactive Evaporation in Organosilicon Vapors.

Dense homogeneous nanocomposite TiSiCN coatings with a thickness of up to 15 microns and a hardness of up to 42 GPa were obtained by the method of reactive titanium evaporation in a hollow cathode arc discharge in an Ar + C2H2 + N2-gas mixture with the addition of hexamethyldisilazane (HMDS). An analysis of the plasma composition showed that this method allowed for a wide range of changes in the activation degree of all components of the gas mixture, providing a high (up to 20 mA/cm2) ion current density. It is possible to widely change the chemical composition, microstructure, deposition rate, and properties of coatings obtained by this method, by changing the pressure, composition, and activation degree of the vapor-gas mixture. An increase in the fluxes of C2H2, N2, HMDS, and discharge current leads to an increase in the rate of coating formation. However, the optimal coatings from the point of view of microhardness were obtained at a low discharge current of 10 A and relatively low contents of C2H2 (1 sccm) and HMDS (0.3 g/h), exceeding which leads to a decrease in the hardness of the films and the deterioration of their quality, which can be explained by the excessive ionic exposure and the non-optimal chemical composition of the coatings.

Oil-lubricated sliding wear performance of TiSiCN-coated ductile iron

Improvements to internal combustion engine performance can be achieved by the application of advanced coatings to piston rings and cylinder bores. Here, the sliding wear performance of TiSiCN coatings on ductile iron was evaluated in heavy-duty diesel engine oil using a block-on-ring tribometer. The coatings were deposited by plasma-enhanced magnetron sputtering of titanium in a reactive environment containing nitrogen, acetylene, and hexamethyldisilazane. Coating characterization was conducted using X-ray spectroscopy and diffraction, electron microscopy, and nanoindentation. TiSiCN adhesion to ductile iron was qualified by Rockwell indentation testing. Wearing surface and counter surface material pairs were systematically varied. Intermittent friction oscillation was observed for self-mated TiSiCN, while tribosystems with only one TiSiCN surface exhibited improved friction stability relative to uncoated ductile iron. A 24% reduction in block wear rate was achieved by coating the block surface with TiSiCN. Solely coating ring surfaces with TiSiCN, however, increased the uncoated block wear rate by over 300%.

Synthesis of Nanocomposite TiSiCN Coatings by Titanium Evaporation and Organosilicon Compound Activation in Hollow Cathode Arc Discharge.

TiSiCN coatings have been obtained by anode evaporation of titanium and the decomposition of hexamethyldisilazane in an arc discharge, using a self-heated hollow cathode, at the pressure rate of 1 mTorr of the Ar+N2 gas mixture. The proposed method makes it possible to independently and widely change the amount of metal and precursor vapor flows, the pressure and composition of the vapor-gas mixture and the degree of ionic interaction on the surface of the growing coating within a single discharge system. The paper presents the method and the results of the effect of a current discharge (10–50 A), and the flux of precursor vapours (0–1 g/h), on deposition rates, compositions, and properties of TiSiCN coatings deposited by an advanced combined PVD+PECVD method. Dense homogeneous TiSiCN coatings up to 6 µm thick and up to 27.5 GPa in hardness were obtained at 7.5 µm/h. The composition of the obtained coatings has been studied by X-ray diffraction and X-ray photoelectron spectroscopy, and it has been shown that the presented methods can form nanocomposite coatings with nanocrystallites TiC, TiN, and TiCxN1−x 3–10 nm in the amorphous matrix based on SiCN.

Effect of the Si/Ti Ratio on the Structure and Mechanical Properties of Plasma-Enhanced Magnetron Sputtered TiSiCN Coatings

Effect of the Si/Ti Ratio on the Structure and Mechanical Properties of Plasma-Enhanced Magnetron Sputtered TiSiCN Coatings

EFFECT OF THE N2/Ar FLOW RATIO ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF TiSiCN COATINGS

TiSiCN coatings were prepared with the multi-arc ion plating and magnetron sputtering technique. The effect of the N2/Ar flow ratio on the properties of TiSiCN coatings was studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and a friction and wear tester (UMT-3). With an increase in the N2/Ar flow ratio, the number of large particles on the surface first increases and then decreases. The intensity of the TiN (200) diffraction peak increases gradually, while the grain size first decreases and then increases. A TiSiCN coating consists of Ti (N, C) nanocrystallites, amorphous SiC, Si3N4 and carbon. When the N2/Ar flow ratio is 5 : 1, the coating exhibits the highest hardness and excellent wear resistance.

Investigation of the plasma composition of a discharge with a self-heating hollow cathode and an active anode in a gas mixture with titanium and hexamethyldisilazane vapors

The analysis of composition of low-pressure (~0.1-1 mTorr) hollow cathode arc plasma in Ar+N2 gas mixture with Ti+hexamethyldisilazane vapors was carried out by optical emission spectroscopy. The influence of HMDS flow rate (1-10 g/h), discharge current (10-50 A) and Ti-vapors flow on hexamethyldisilazane decomposition degree and plasma composition and was investigated. The proposed plasma activation method provides both an intense flow and a high activation degree of metal vapors, and a sufficient decomposition degree of precursor vapors for the formation of solid TiSiCN coatings at a high deposition rate. Test coatings with a thickness of 6 microns and a hardness of 31 GPa were obtained in 1 hour at 400ºC.

Obtaining of TiSiCN coatings by anodic evaporation of titanium and decomposition of hexamethyldisilazane in a low-pressure arc discharge

The method of TiSiCN-coatings deposition by anodic evaporation of Ti and decomposition of an organosilicon precursor (hexamethyldisilazane) in a low-pressure (∼1 mTorr) nitrogen-argon arc discharge with a self-heated hollow cathode is investigated. The plasma composition was analyzed by optical emission spectroscopy. TiSiCN coatings with a thickness of up to 10 microns and a hardness of up to 30 GPa were obtained in 1.5 hours at a temperature of 400°C.

Effect of carbon addition on tribological performance of TiSiN coatings produced by cathodic arc physical vapour deposition

Effect of carbon addition on tribological behaviour of multilayered TiSiN coating was investigated and the performance of TiSiCN and TiSiN coatings on cold forming steel dies were compared. The coatings were deposited by an industrial cathodic arc physical vapour deposition process. Surface analysis by X-ray diffraction and micro-Raman spectroscopy revealed that structure of TiSiN was mainly composed of TiN crystallites together with a silicon-rich amorphous phase. In the case of TiSiCN coating, presence of Ti(C, N) crystallites, graphite and amorphous carbon were identified. Both coatings contained high compressive residual stresses, as measured by sin2ψ method. Nanoindentation testing showed hardness values of 25 GPa and 29 GPa for TiSiN and TiSiCN, respectively. Tribological tests, conducted on a ball-on-disc wear tester using zirconia ball, indicated lower coefficient of friction of the coatings as compared to the steel substrate; the lowest value of 0.2 was experienced by TiSiCN coated surface. Study of wear mechanisms proved that application of coatings changed the prevailing wear mode from adhesive to abrasive, decreasing the wear rate to one third. Addition of carbon to TiSiN changed tribological behaviour of the coating, similar to a self-lubricant film. Field tests of TiSiCN coating on forming dies, for deep drawing operation of steel tubes, revealed 10 times increase of die lifetime.

Enhanced discharge and surface properties of TiSiCN coatings deposited by pulse-enhanced vacuum arc evaporation

Pulse-enhanced vacuum arc evaporation (PEVAE), an advanced version of conventional DC vacuum arc evaporation, generates a high flux of electrons to ionize more gaseous and metallic atoms in the deposition system to facilitate coating deposition. Compared to the conventional DC mode, the highly ionized plasma improves the structure and properties of the coatings deposited by the PEVAE mode. To obtain a better understanding and evaluate the advantages and limitations of this technique, we conduct a comparative study on TiSiCN coatings deposited by the traditional DC mode and PEVAE mode for different target-to-substrate distances (Dt-s) in the reactive environment of HMDSN. The substrate current is determined by an oscilloscope and optical emission is monitored by a miniature fiber-optics spectrometer. The microstructure and properties of the coatings are characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, indentation test, nanoindentation, electrochemical measurement, and ball-on-disk wear test. The results demonstrate that the average substrate current increases by 53.8% as Dt-s increases from 200 mm to 300 mm. The pulsed current discharge in the HMDSN atmosphere increases the deposition rates by up to 36.4% and Ebi increases by 29% reflecting a denser microstructure. The PEVAE mode improves the microstructure of the TiSiCN coatings as well as resistance to corrosion and wear. Furthermore, it has good processing adaptability for different target-to-substrate distances.

Tribocorrosion behaviors of TiSiCN nanocomposite coatings deposited by high power impulse magnetron sputtering

High-performance coatings originated in ingenious coating designs and advanced preparation techniques are expected to fulfill imperious demands in propulsion, bearings and mechanical seals, etc in marine systems for seawater lubrication. In this work, TiSiCN nanocomposite coatings were deposited by high power impulse magnetron sputtering at a power of 4–8 kW. As power is increased, TiSiCN coatings possess nanocrystalline (TiN, TiC, TiCN)/amorphous (Si3N4, SiC, sp2-C) nanocomposite structure without distinctly preferred orientation. The highest hardness (H) of 43 GPa and effective Young’s modulus (E*) of 360 GPa were achieved at 8 kW, while the highest H/E* of 0.123 and H3/E*2 of 0.61 appear at 7 kW due to refined nano-grains, uniform distribution, high surface/interface integrity and fully dense microstructure. Rockwell C adhesion level increased from HF2 at 4 kW to HF1 at 8 kW. TiSiCN coatings with high H, H/E*, H3/E*2 and adhesion exhibit high open circuit potential of −0.07 V, low friction coefficient of 0.25 and specific wear rate of 4.78 × 10−5 mm3 N−1 m−1, resulting from mild abrasive wear without the occurrence of pitting corrosion in 3.5 wt.% NaCl aqueous solution. Moreover, cycling tribocorrosion tests revealed that passive films possess strong abilities of regeneration and self-repairation on sliding contact surface.

Improvement of CoCr Alloy Characteristics by Ti-Based Carbonitride Coatings Used in Orthopedic Applications

The response of the human body to implanted biomaterials involves several complex reactions. The potential success of implantation depends on the knowledge of the interaction between the biomaterials and the corrosive environment prior to the implantation. Thus, in the present study, the in vitro corrosion behavior of biocompatible carbonitride-based coatings are discussed, based on microstructure, mechanical properties, roughness and morphology. TiCN and TiSiCN coatings were prepared by the cathodic arc deposition method and were analyzed as a possible solution for load bearing implants. It was found that both coatings have an almost stoichiometric structure, being solid solutions, which consist of a mixture of TiC and TiN, with a face-centered cubic (FCC) structure. The crystallite size decreased with the addition of Si into the TiCN matrix: the crystallite size of TiCN was 16.4 nm, while TiSiCN was 14.6 nm. The addition of Si into TiCN resulted in smaller Ra roughness values, indicating a beneficial effect of Si. All investigated surfaces have positive skewness, being adequate for the load bearing implants, which work in a corrosive environment. The hardness of the TiCN coating was 36.6 ± 2.9 GPa and was significantly increased to 47.4 ± 1 GPa when small amounts of Si were added into the TiCN layer structure. A sharp increase in resistance to plastic deformation (H3/E2 ratio) from 0.63 to 1.1 was found after the addition of Si into the TiCN matrix. The most electropositive value of corrosion potential was found for the TiSiCN coating (−14 mV), as well as the smallest value of corrosion current density (49.6 nA cm2), indicating good corrosion resistance in 90% DMEM + 10% FBS, at 37 ± 0.5 °C.

Microstructure, mechanical properties and cutting performances of TiSiCN super-hard nanocomposite coatings deposited using CVD method under the guidance of thermodynamic calculations

A general strategy for the development of TiSiCN super-hard nanocomposite coatings was proposed in the present work. Subsequently, TiSiCN coatings with promising industrial applications for cutting tools were prepared from gaseous mixtures of TiCl4, SiCl4, CH3CN, NH3/N2 and H2 by a low pressure chemical vapor deposition (CVD) process under the guidance of established phase diagrams. The chemical compositions, microstructure, mechanical properties and cutting performances of TiSiCN coatings were investigated. No Si was doped into MT (moderate temperature)-Ti(C,N) with N2 addition while higher Si contents (2.87–6.43 at.%) were obtained by using NH3. The measured compositions and phase assemblages of TiSiCN coatings were reasonably described by thermodynamic calculations. TiSiCN coatings showed nanocomposite structures consisting of nanocrystalline TiCxNy and amorphous SiCxNy. A maximum hardness (44.9 ± 0.9 GPa), ratios of H/E⁎ and H3/E⁎2 (H-hardness, E*-effective elastic modulus) were obtained for TiSiCN coating with a Si content of 2.87 at.% and a grain size of 37.7 nm, indicating enhanced mechanical properties to those of the previous works. TiSiCN displayed a superior cutting performance compared to MT-Ti(C,N) during continuous wet turning of nodular cast iron (DIN GGG40). It also exhibits a better wear resistance than state-of-the-art thicker MT-Ti(C,N) + Al2O3 multilayer coating during dry milling of the same material. TiSiCN coatings with better performances could be designed with the aid of the CVD phase diagrams in this work.

A comparative study of the mechanical and tribological properties of PECVD single layer and compositionally graded TiSiCN coatings

In this study, TiSiCN coatings, with and without a Ti/TiN/TiCN interlayer, are deposited on tempered and plasma-nitrided H13 hot-working tool steel substrate by pulsed direct current plasma enhanced chemical vapor deposition. The self-lubricant super hard TiSiCN coatings have a nanocomposite structure consisting of an amorphous SiCN matrix embedding TiCN nanocrystals. In the presence of the graded interlayer, coating adhesion improves significantly, as revealed by a 40% increase of the critical load for adhesion failure in scratch testing of the coated samples. The formation of shorter radial cracks around the indentation zone during Rockwell C indentation test reveals that the coating with the graded interlayer has a higher toughness compared to the single layer coating. The wear rate of the graded coating is found to be about three times lower than that of the single layer coating, which can be attributed to the higher hardness, better adhesion to the substrate and higher toughness of the graded coating.

Electrochemical and Tribological Properties of TiSiCN Coatings in Coolant

TiSiCN coatings were prepared using DC and RF magnetron co-sputtering system. The influence of target powers on phase structures, mechanical properties, tribological and electrochemical properties were studied. The results indicated the coatings presented an amorphous structure, and the highest microhardness of 1566.4 HV was obtained at a target power of 200 W. In terms of the electrochemical properties in coolant, the higher charge transfer resistance of 2.64 × 107 Ωcm2 and the polarization resistance (~1.10 × 108 kΩ.cm2) were obtained at low target power, indicating a better corrosion resistance. Furthermore, the friction coefficient was 1.01 ~ 1.14 as sliding against SUS440C balls in air. In contrast, the friction coefficient decreased to 0.45 ~ 0.58 in coolant, and the wear mechanism changed from oxidation wear into abrasive wear.

Structure and properties of TiSiCN coatings with different bias voltages by arc ion plating

TiSiCN coatings were deposited on 316 L steel using the multi-arc ion plating system. All the coatings had the same total thickness of approximately 1.6 µm. The TiSiCN coatings were deposited under the mixture constant flow of N2 and C2H2 but varying bias. Information about structures, composition and properties were characterized by scanning electron microscope, x-ray diffraction, x-ray photoelectron spectroscopy, nanoindentation and ball-on-plate wear tests. The results show that all of the coatings consist of a TiCN nano-crystal phase and an Si3N4 amorphous phase. With an increase in the bias, the film becomes denser and exhibits better tribological behavior and mechanical properties. Moreover, the bonding strength between the coatings and the substrate increased and the resistance to thermal shock intensified when the coatings were made at a higher bias voltage.

The effects of phase transformation on the structure and mechanical properties of TiSiCN nanocomposite coatings deposited by PECVD method

In the present study, the effects of phase transformations on the structure and mechanical properties of TiSiCN coatings were investigated. TiSiCN nanocomposite coatings were deposited on AISI H13 hot-work tool steel by a pulsed direct current plasma-enhanced chemical vapor deposition process at 350 or 500 °C, using TiCl4 and SiCl4 as the precursors of Ti and Si, respectively, in a CH4/N2/H2/Ar plasma as the source of carbon and nitrogen and reducing environment. Some samples deposited at 350 °C were subsequently annealed at 500 °C under Ar atmosphere. Super hard self-lubricant TiSiCN coatings, having nanocomposite structure consisting of TiCN nanocrystals and amorphous carbon particles embedded in an amorphous SiCNx matrix, formed through spinodal decomposition in the specimens deposited or annealed at 500 °C. In addition, it was revealed that either uncomplete or relatively coarse phase segregation of titanium compounds was achieved during deposition at 350 °C and 500 °C, respectively. On the contrary, by deposition at 350 °C followed by annealing at 500 °C, a finer structure was obtained with a sensible improvement of the mechanical properties of coatings. Accordingly, the main finding of this work is that significant enhancement in key properties of TiSiCN coatings, such as hardness, adhesion and friction coefficient, can be obtained by deposition at low temperature and subsequent annealing at higher temperature, thanks to the formation of a fine grained nanocomposite structure.

TiSiCN and TiAlVSiCN nanocomposite coatings deposited from Ti and Ti-6Al-4V targets

TiSiCN and TiAlVSiCN coatings were deposited by pulsed dc magnetron sputtering of a pure Ti target and a commercial grade Ti-6Al-4V target, respectively, in an Ar+N2+trimethylsilane (TMS) mixture. The elemental composition of the coatings was varied by increasing the TMS flow rate (fTMS) from 0 to 4sccm. The main goal of the study is to explore the possibility of using low cost commercial grade Ti-6Al-4V material as a sputtering source of Ti for depositing Ti based nanostructure coatings. The microstructure of the coatings was characterized using X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The mechanical properties, sliding wear and erosion resistances of the coatings were analyzed using nanoindentation, dry ball-on-disc test, and solid particle erosion, respectively. Higher deposition rates (35–59% increase) were observed for the TiAlVSiCN coatings than those for the TiSiCN coatings under similar deposition conditions. As the fTMS is increased, both coating systems exhibit similar structural evolution from fine columnar grain structure to nanocomposite structure, and finally to amorphous-like structure. The incorporation of a small amount of Al and V into the TiAlVSiCN coatings directly from the Ti-6Al-4V target is beneficial for improving the mechanical properties, wear resistance, and erosion resistance of the coatings. The study demonstrates that it is practical to use commercial grade Ti-6Al-4V material as a sputtering source of Ti for depositing Ti-based nanostructure coatings to achieve higher deposition rates, improved properties and lower production cost.