Titanium Carbonitride Coatings Research Articles

Investigation of thin titanium carbonitride coatings deposited onto stainless steel

Titanium carbonitride (TiCN) coatings are commonly used in a variety of applications, from microelectronics to high-performance cutting tools. The TiCN coatings grown by chemical vapor deposition are especially attractive because this technique provides a very high degree of control during the procedure. A gas-phase deposition utilizing an organometallic precursor molecule, tetrakis-dimethylamino-titanium was used to grow thin TiCN coatings onto 4140 series steel prepared and cleaned in vacuum. A highly controlled conformal filling was achieved by the deposition performed onto a sputter-cleaned steel surface held at 600K. The film of the overall Ti:C:N composition of 1:1:1 was produced, as demonstrated by Auger electron spectroscopy. In air, these coatings are oxidized but maintain their uniformity, as demonstrated by time-of-flight secondary ion mass spectrometry. The chemical state of the elements in the coatings was investigated by the X-ray photoelectron spectroscopy and the morphology of the films produced was investigated by atomic force microscopy. Finally, the initial mechanical testing of the films was performed by comparing Young's modulus to that of the underlying steel.

Characteristics of TiCN Film on AZ31 Magnesium Alloy Deposited by Radio Frequency Magnetron Sputtering

Titanium carbonitride (TiCN) films were deposited on AZ31 magnesium alloy by radio frequency magnetron sputtering. The surface morphology and microstructure were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the corrosion resistance was studied by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results show that TiCN coatings deposited on AZ31 magnesium alloy are amorphous, and reveal good adhesion onto the substrate. The corrosion current density of TiCN-coated magnesium alloy was 1.664×10-6 A/cm2, which decreased by more than one order of magnitude compared to the uncoated magnesium alloy (1.785×10-5 A/cm2).

Synthesis and microstructure observation of titanium carbonitride nanostructured coatings using reactive plasma spraying in atmosphere

In the present study, nanostructured titanium carbonitride (TiCN) coatings were successfully deposited by reactive plasma spraying (RPS) technology using a self-designed gas tunnel mounted on a normal plasma spray torch. The phase composition and microstructure of the TiCN coatings were characterised by XRD, SEM and TEM. The results indicated that the main phase of the coatings was FCC TiC 0.2N 0.8 with a small amount of Ti 3O. The coating that was deposited using 35 kW displayed better microstructure and properties. The coating exhibited a typical nanostructure including 90 nm diamertrical equiaxed grains and 400 nm long columnar grains by TEM images. The SEM observation further revealed that the equiaxed grains in parallel direction to the substrate surface in TEM images were actually the columnar grains perpendicular to the substrate surface. The formation mechanism of the nanostructured coatings was also discussed. The measured microhardness value of the coating was approximately 1659 Hv 100 g , and the calculated crack extension force was about 34.9 J/m 2.

Combined plasma-vacuum processing of wood-cutting tools

The influence of the regimes of the combined vacuum-plasma processing on the structure, phase composition, and microhardness of the modified layers and the titanium carbonitride coatings formed on samples of R6M5 high-speed steel is investigated. The combined processing involves ion nitration in a glow discharge plasma and the deposition of coatings using arc plasma.

Wear‐Resistant Titanium Carbonitride Coatings onto WC–Co Cutting Tools by Pulsed High‐Energy Density Plasma

Nanometer grain superhard ternary Ti(C,N) coatings with Vicker's nanohardness more than 50 GPa were deposited onto WC–Co cutting tools at ambient temperature using pulsed high‐energy density plasma coaxial gun. Young's modulus of the coated tools was about 550 GPa. Because of the continuously graded interfaces between the coatings and substrates, the coatings are well adherent to the tool substrates with very high critical load up to more than 100 mN measured by nanoscratch tester. The coefficients of friction were lower than 0.1. In contrast with the uncoated tools, the coated tools could be applied in turning hardened CrWMn steel at high speed under industrial conditions without lubricants, and the cutting performances were greatly improved with rather low flank wear and long tool life.

An Investigation of Tribological Properties of CN and TiCN Coatings

Today the tool industry on a worldwide basis uses hard, wear-resistant, and low-friction coatings produced by different processes such as electrochemical or electroless methods, spray technologies, thermochemical, chemical-vapor deposition (CVD), and physical vapor deposition (PVD). In the current work, two different coatings, nitrocarburized (CN) and titanium carbonitride (TiCN) on M2-grade tool steel, were prepared by commercial diffusion and PVD techniques, respectively. Properties such as thickness, roughness, and hardness were characterized using a variety of techniques, including glow-discharge optical emission spectrometry (GD-OES) and scanning electron microscopy (SEM). A crossed-cylinders wear-testing machine was used to investigate the performances of both coatings under lubrication. The effect of coatings on the performance of lubricants under a range of wear-test conditions was also examined. Degradation of lubricants during tribological testing was explored by Fourier transform infrared (FTIR) spectroscopy.

Structure and properties of the TiN and Ti(C,N) coatings deposited in the PVD process on high-speed steels

This paper presents investigation results of the influence of substrate type made from the W–Mo–V+Si high-speed steels with addition of Nb or Ti, or else from the Mo–V–Co+Si steel with the economically selected chemical composition, and from the sintered steels of the ASP 23 and ASP 30 types, on structure and properties of the hard, wear resistant, TiN, titanium nitride, and Ti(C,N), titanium carbonitride coatings, put down in the PVD process. It was demonstrated that the high-speed steels containing 9–11% of tungsten, 2% of molybdenum, 0.7% of silicon, in which vanadium was partially substituted by 0.5% of niobium or 0.3% of titanium, covered with the investigated coatings in the PVD process, demonstrate properties comparable to those obtained on the sintered high-speed steels of the ASP 23 and ASP 30 types. It was found out that the investigated TiN and Ti(C,N) coatings display the columnar structure with the clear axial texture {111}, with the solidified titanium drops deposited directly onto the substrate or coating layers developed earlier, and also with pits developed by falling out by some of these drops. The TiN and Ti(C,N) coatings display a good adhesion to the substrates from the investigated high-speed steels, and it is not only the adhesion deciding this but also the diffusion or ion implantation connected mix of elements in the transition zone between the coating and its substrate. The Ti(C,N) coatings display double erosion resistance compared to the TiN ones. The erosion resistance grows along with increasing of the coating hardness, whereas neither the critical load value in the adhesion test, nor the chemical composition do not have any significant effect. This makes it possible to exploit in practice high-speed steels with the relatively low concentration of the alloying elements instead of the high-alloy cobalt steels, provided the substrate’s heat treatment is made so that it ensures its maximum secondary hardness. Moreover, a new methodology was developed for evaluation of the erosion resistance of materials coated in the PVD process, employing the computer image analysis on the scanning electron microscope.

Effect of carrier gas on the deposition of titanium carbo-nitride coatings by a novel organo-metallic plasma immersion ion processing technique

Using a novel organo-metallic chemical vapor deposition plasma immersion ion processing technique, titanium carbo-nitride (Ti–C–N) coatings were deposited from an organo-metallic CVD precursor, tetrakis-dimethylamino titanium. Different carrier gases (acetylene, ammonia, argon and nitrogen) were made to flow through the precursor reservoir at 20 sccm so that the coating composition could be modified. Deposited coatings had thickness in the range of 300–1000 nm as determined by surface profilometry. Titanium concentrations in the coatings ranged from 10.8 to 15.1 at%. Hardness values of these coatings ranged from ≈8–14 GPa while residual stresses were in the range from −440 to −100 MPa, as determined by nanoindentation and wafer curvature techniques, respectively. Coefficient of friction values ranged from 0.2 to 0.45, and were lowest for coatings with low titanium content. Hardness, coefficient of friction and residual stress increased with increasing titanium content. Wear resistance was determined by a pin-on-disk technique and wear coefficients ranged from 0.005×10 −6 to 2×10 −6 mm 3/N m, increasing with increasing hardness indicating an abrasive wear mechanism.

Synthesis and characterization of TiC and TiCN coatings

Thin film coatings of titanium carbide (TiC) and titanium- carbo-nitride (TiCN) were deposited on Si(100) substrates using the pulsed laser deposition (PLD) method. The PLD method is a unique process for depositing high-quality thin films with novel microstructure and properties. Mechanical properties of TiCN are found to be dependent on the nitrogen ambient during deposition. For nitrogen ambient pressure of 20 mTorr the TiCN has hardness values close to TiN hardness values, whereas for nitrogen ambient pressure of 5 mTorr the hardness values of the TiCN films are comparable to the hardness values of the TiC films.

Analysis of wear behaviour of titanium carbonitride coatings

The kinetics of chemical reactions occurring during the coating process and the wear behaviour of Ti(C,N) coatings, including variations in wear displacement with the temperature of the lower specimen, were investigated in this work. The variations in the wear displacement and the temperature of the lower specimen are regressed by an eight-order polynomial function. The lower specimens were coated by a titanium film as underlayer and three kinds of coating material including TiN, Ti(C,N) or TiC were deposited as the top layer. The Ti(C,N) coatings were prepared by varying the gas flow rates of nitrogen and acetylene to form eight kinds of specimen. The tribological behaviour demonstrated by these eight specimens is discussed. The experimental data for the atomic ratios of [C] and [N] can be well expressed using the theory of diffusion rate and the theory of reaction rate for the deposition of ceramic coatings. The variations in the wear displacement gradient with the temperature of the lower specimen can give information on the adhesive behaviour arising before and after three-body wear. The wear rates of the upper and lower specimens due to adhesive wear are dependent on the operating conditions. The specimen with a higher final wear displacement was likely to produce on the upper specimen a higher wear rate when operating at 0.705 m s −1. The thicker the adhesive layer, the lower the wear rate of the lower specimen produced. When the sliding speed was elevated to 1.41 m s −1, the specimen with a higher final wear displacement often produced a lower wear rate on the upper specimen, and also caused higher wear rates on the lower specimens.

The tribological characteristics of titanium carbonitride coatings prepared by cathodic-arc ion plating technique

The tribological behavior of specimens coated by two layers, titanium carbonitride film as the top layer and titanium film as the underlayer, is studied in this work. The coating layers were deposited using the cathodic-arc ion plating process (CA) technique. Experiments were carried out on a wear test machine using a thrust-washer adapter to simulate the surface contacts between the steel ring (the upper specimen) and the titanium carbonitride coated washer (the bottom specimen). We address the influence of the thickness of the two coating layers on tribological behavior, the wear mechanism, specimen hardness, coating morphology, and adhesive strength. Higher measured values of electrical voltage are always obtained in the specimens with lower adhesion strength. A thin titanium carbonitride film with a thick titanium underlayer decreases the adhesion strength, resulting in a higher wear rate. The effect of surface morphology on specimen wear rate is dependent upon the sliding speed and the coating thickness. When the specimen's sliding speed is raised, both the wear rates and the friction coefficients decrease significantly.

X-Ray diffraction investigations of magnetron sputtered TiCN coatings

X-ray diffraction measurements were performed on titanium carbonitride coatings produced in an electron enhanced, unbalanced magnetron system. The films were deposited onto AISI 316 stainless steel substrates with an argon background pressure in the range of 0.1 Pa. A gas mixture of nitrogen and acetylene was introduced in different ratios, which alters the carbon-to-nitrogen ratio in the coating. The composition of the film was determined by glow discharge optical emission spectroscopy and wavelength-dispersive X-ray analysis. The morphology of the films was determined by scanning electron microscopy. The peak positions, integral breadths and shape parameters were determined by X-ray diffraction, and the composition influence on these parameters was investigated. The applied X-ray diffraction methods were conventional Bragg-Brentano diffraction and also parallel beam low angle diffraction. Morphological and microstructural features are found which indicate that an increased carbon content in the film gives similar results to a decrease in bias voltage.

Preparation of Titanium Carbonitride Coatings by the Sol-Gel Process

ABSTRACTTi(NPri2)4 has been synthesized and used as a precursor for aminolysis andpolymerization by reaction with isopropylamine. The resultant dark red solution was utilized for dip coating of silicon substrates. Firing of these coatings in N2 or Ar produced dense and crack-free titanium carbonitride coatings.

Plasma-assisted chemical vapour deposition of hard coatings with metallo-organic compounds

In this work the use of two metallo-organic compounds, titanium tetrakisdialkylamides, was investigated with a pulsed d.c. plasma-assisted chemical vapour deposition process to deposit layers on steel substrates and hard metals. The layers have been studied by scanning electron microscopy X-ray diffraction and wavelength-dispersive X-ray analysis. It is shown that chlorine-free titanium carbonitride coatings can be obtained by metallo-organic chemical vapour deposition even at substrate temperatures of lower than 450°C.

Plasma-assisted chemical vapour deposition with titanium amides as precursors

One possible way of reducing the high deposition temperatures required for conventional chemical vapour deposition (CVD) is the application of metal-organic compounds; a second is the excitation of the precursors in a glow discharge. In the production of wear-resistant coatings such as TiN in a low temperature plasma-assisted CVD process, the use of TiCl 4 can cause corrosion as well as producing coatings of undesirably low hardness. To avoid these problems, the application of a metal-organic precursor and plasma enhancement of the CVD process were combined in this investigation. Two titanium amides, Ti(N(CH 3) 2) 4 and Ti(N(C 2H 5) 2) 4, both liquids with sufficient volatility, were used together with hydrogen and argon in a d.c. glow discharge at a total pressure of approximately 1 mbar. The temperature of the steel substrates during deposition was varied from 200 to 500 °C. It was established by means of glow discharge optical spectrometry and X-ray diffraction that titanium carbonitride coatings were obtained. The morphology of the Ti(C,N) layers was examined by scanning electron microscopy. Up to a temperature of 400 °C fine-grained polycrystalline layers were observed whose hardness measured more than 2000 HV. At 500 °C thermal decomposition of the metal-organic compounds by a homogeneous reaction became dominant and reduced the quality of the coating.

Ion-plated titanium carbonitride films

The performance of newly developed titanium carbonitride coatings in cutting and forming operations is discussed, specifically in comparison with titanium nitride. It is shown that titanium carbonitride is to be recommended when abrasion is the main wear mechanism, though it also has advantages in reducing adhesive wear. When interrupted cutting is encountered, titanium nitride coatinhs are shown to be preferable.