Chemical Vapor Deposition Coatings Research Articles

Phase composition, microstructure and mechanical properties of CVD Ti–B–N coatings deposited at different temperatures guided by thermodynamic calculations

TiBN coatings, as materials with broad potential applications, have received much attention in surface engineering in recent years. Within this work, the chemical vapor deposition (CVD) phase diagrams of TiBxNy coatings were calculated and the effects of deposition temperature (830–920 °C) on the microstructure, phase composition and mechanical properties of CVD TiBxNy coatings were investigated. The TiB0.61N0.84 and TiB0.61N0.81 coatings deposited at 830 and 860 °C have a particle-like surface, the TiB0.56N0.88 and TiB0.55N0.92 coatings deposited at 890 and 920 °C exhibit needle-like characteristic. XPS and TEM results indicate that TiBxNy coatings consist of nanocrystalline TiN and TiB2 embedded in amorphous TiB and BN matrix. The TiB0.61N0.84 coating exhibits the highest hardness of 40.7 GPa. The hardness of the coatings decreases as the deposition temperature increases. The presently developed approach of thermodynamic calculations and key experiments is equally valid for the efficient deposition of other CVD coatings.

Stretch‐tolerant PECVD gas barrier coatings for sustainable flexible packaging

AbstractThis study employs X‐ray photoelectron spectroscopy (XPS), thickness measurements, permeation analysis and laser scanning microscopy to analyse the stretch tolerance in dependence of the chemical composition and deposition rates of plasma‐enhanced chemical vapour deposition coatings. SiOx and SiOCH coatings are deposited on polyethylene terephthalate film using a full factorial study design of three parameters (monomer/oxygen mass flow and pulse duration). They exhibit distinct differences, with the monomer mass flow emerging as a critical factor influencing deposition rates and stretch tolerance. SiOCH coatings demonstrate faster growth rates due to higher monomer flow. SiOx coatings exhibit superior barrier performance. Stretch tolerance does not solely correlate with atomic composition, since a SiOx coating with higher‐than‐predicted stretch tolerance was observed.

Towards a Better Understanding of the Back-Side Illumination Mode on Photocatalytic Metal–Organic Chemical Vapour Deposition Coatings Used for Treating Wastewater Polluted by Pesticides

Pesticides are emerging contaminants that pose various risks to human health and aquatic ecosystems. In this work, diuron was considered as a contaminant model to investigate the influence of the back-side illumination mode (BSI) on the photocatalytic activity of TiO2 coatings grown on Pyrex plates by metal–organic chemical vapour deposition (MOCVD). A photoreactor working in recirculation mode was irradiated at 365 nm with ultraviolet A (UVA) light-emitting diodes in BSI. The degradation of diuron and its transformation products was analysed by high-performance liquid chromatography, ion chromatography, and total organic carbon analysis. The coatings were characterised by X-ray diffraction analysis and scanning electron microscopy. Five coatings containing 3, 7, 10, 12 and 27 mg of TiO2 exhibited different morphology, crystallinity, thickness and photocatalytic activities. The morphology and crystallinity of the coatings had no significant influence on their photocatalytic activity, unlike their mass and thickness. TiO2 contents less than 10 mg limit the photocatalytic activity, whereas those greater than 15 mg are inefficient in the BSI because of their thickness. The maximum efficiency was achieved for coatings of thickness 1.8 and 2 µm with TiO2 contents of 10 and 12 mg, revealing that the photocatalyst thickness controls the photocatalytic efficiency in the BSI.

Experimental and Numerical Study on Friction and Wear Performance of Hot Extrusion Die Materials.

For the aluminium alloys produced by the hot extrusion process, the profile is shaped according to the bearing at the exit of the extrusion die. The tribological process has significant effects on the die service life, profile dimensional tolerances, and profile surface finish. Recently, new technologies have been introduced to the hot extrusion die, such as cemented carbide insert die and surface coating. However, under hot extrusion working conditions, quantitative studies on their friction and wear performances are lacking. In this work, the friction and wear performances of three typical extrusion die materials, traditional hot tool steel (H13), cemented carbide (YG8), and chemical vapour deposition (CVD) coating, were studied. Macro and nano hardness tests, Pin-on-disk friction and wear tests, optical profiler and SEM observations, and experiments and simulations of hot extrusion were conducted. The results show that the coefficients of friction of CVD coatings and H13 hot work tool steel specimens were smaller under the hot extrusion condition than at room temperature. The wear mechanisms of H13, YG8, and CVD coatings at 500 °C are adhesion, abrasive, and fatigue, respectively. Moreover, the tribology results were validated by the extrusion experiments and the finite element analysis of hot extrusion. The conclusion of this manuscript is useful not only for the numerical simulation of the hot extrusion process but also for the surface finishing of the extrusion profile.

Design of Comb Crack Resistant Milling Inserts: A Comparison of Stresses, Crack Propagation, and Deformation Behavior between Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 CVD Coatings

Investigations on comb crack resistance of milling inserts coated with chemical vapor deposition (CVD) Ti(C,N)/α-Al2O3 and Zr(C,N)/α-Al2O3 showed a distinct wear evolution in both systems. Wear studies revealed that the appearance of comb cracks is connected to the initial CVD cooling crack network. Micropillar compression tests indicated a brittle intergranular fracture mechanism for the Ti(C,N) layer and a transgranular fracture accompanied with signs of plastic deformation for the Zr(C,N) coating. Additionally, for the Zr(C,N) based system, a compressive stress condition in the temperature range of interest (200–600 °C) was determined by in-situ synchrotron X-ray diffraction. The set of residual compressive stresses together with the ability of the Zr(C,N) layer to deform plastically are key features that explain the enhanced resistance to comb crack wear of the Zr(C,N) based system in milling of cast iron.

Growth and Properties of TiN/Al2O3/Ti(C, N)/TiN Multilayer CVD Coatings on Ti (C, N)-Based Cermet Substrates with Ni, Co and Fe Binders

In this article, Ti (C, N)-based cermets with Ni, Co and Fe binder phase were manufactured by traditional powder metallurgical techniques. The multilayer TiN/Al2O3/Ti (C, N)/TiN CVD (chemical vapor deposition) coatings were deposited on the three kind of cermets, and the growth and properties of the coatings were studied. The results show that massive cores-incomplete rims are found in the cermet-Ni (cermets with Ni binder) and cermet-Fe (cermets with Fe binder), while in the cermet-Co (cermets with Co binder), the small black cores are surrounded by a complete and well-developed rim phase. When the TiN coating is deposited on the cermets with cores-incomplete rims, the Ti and N atoms stack on the face-centered cubic structure of Ti (C, N) first, and epitaxial growth of the TiN crystals takes place. The epitaxial growth is attributed to the same preferred orientation (2 0 0) of the TiN layers to the Ti (C, N) of the substrate. While on the cermets with cores-complete rims, (Mo, Ti) (C, N) solid solution and binder phase (Ni/Co/Fe), which has a distinct crystal structure or lattice parameters, TiN grains nucleate first and then grow. In this case, the TiN coatings show a (1 1 1)-oriented structure. Dense and thin coatings grow on the cermets-Co. The adhesion of the multilayer coatings to the substrate increases in the order cermets-Fe, cermets-Ni and cermets-Co. In addition, the coating on the cermets-Co has the lowest COF (coefficient of friction) as the thin TiN layer (0.7 μm) is propitious to diffusion of Al and O, and a protective transfer layer is formed by AlOx.

Structure and high temperature wear characteristics of CVD coating on HEA-bonded cermet

Ti(C,N)-based cermets with a CoCrFeMnNi high-entropy alloy (HEA) binder phase were coated via chemical vapor deposition (CVD). The influence of the HEA-bonded cermet substrate on the microstructure, orientation, adhesion, and high temperature frictional wear performance of the CVD coating was investigated. The results indicate that the HEA binder phase inhibits the growth of cermet grains and provides more nucleation sites for the coating. Thus, the coating on the HEA-bonded cermet has a smaller grain size. The substitution of HEA for the Ni binder phase increases the entropy value of the cermet system, resulting in a decrease in free energy. In the early stage of CVD, the gas atoms adsorbed on the solid surface with low free energy are in a more stable thermodynamic state, which enhances the adhesion strength between the coating and substrate. During high temperature frictional wear, the friction coefficient of the coating on Ni-bonded cermet is less than that of the coating on HEA-bonded cermet because of iron oxide lubricating films. However, the wear rate exhibits a reverse trend. The coating on the HEA-bonded cermet has the best wear resistance due to small grain size, superior hardness and excellent adhesion strength. The wear forms present in the CVD coatings are abrasive wear, adhesive wear and oxidation wear.

ON COMPLEXATION IN PROCESS OF CHEMICAL COPPER PLATING FROM SOLUTIONS CONTAINING POLYVINYLPYRROLIDONE

A formation of multifunctional composite coatings with a copper matrix by chemical vapor deposition is an effective method of modifying the surface of metals and non-metals and the increase in the deposition rate of coatings. It is important that the copper complex compounds are formed during chemical vapor deposition coatings and are included in the coatings composition. During the work by methods of thermogravimetric analysis and IR spectroscopy the composite coatings with copper matrix obtained from solutions containing copper sulphate and polyvinylpyrrolidone were studied. The results of thermogravimetry and IR spectroscopy of these components were presented. Samples of composite coatings for IR spectroscopy were obtained as a suspension of the coatings in vaseline oil. Deposited coating was scraped off from the substrate, and then was triturated in an agate mortar with vaseline oil until they formed a stable not stratified suspension. These suspensions were analyzed. The samples for thermogravimetry containing copper sulfate and polyvinylpyrrolidone were obtained by mixing these components. The following proofs of interaction in polyvinylpyrrolidone - copper sulphate system with forming a complex of polyvinylpyrrolidone - copper and includings of this complex into the coating were obtained. The differences of thermogravimetric curves of the mixture CuSO4 5H2O and polyvinylpyrrolidone were established. They are softening temperature increasing in the polymer material on 30 ... 35 °С towards to the softening temperature of polyvinylpyrrolidone, the appearance of the endothermic process, probably associated with the interaction of the polyvinylpyrrolidone with the copper, and the increase in the thermal stability of the polymer component of the system on 50-60 °С, which can be also with the result of complexation of polyvinylpyrrolidone - copper. The estimated structure of this complex, which reflects the results of the IR-spectrogram of the composite coatings analysis was presented. The IR spectra have absorption bands with wave numbers corresponding to the stretching vibrations of C-H bonds in the aromatic ring of polyvinylpyrrolidone, the stretching vibrations of the group – CH2 - and C-N bonds, which are also typical for the polyvinylpyrrolidone. This indicates the presence of polyvinylpyrrolidone in the coating or in its complex compound. In the spectra of the coatings the absorption bands in the range of 1750-1250 cm-1 are presented, which correspond to the stretching vibrations of C=O in the aromatic part of polyvinylpyrrolidone compound, in particular, in the group -CONHR, but they are shifted on about 50 cm-1 with respect to the same bands in the spectra of polyvinylpyrrolidone solution. Such shift is typical for the complex compounds of polyvinylpyrrolidone - copper which caused the C=O bond deformation, which occurs during the formation of additional bond of oxygen and copper atoms: C=O ∙∙∙ Cu, and indicates the presence of such complexes in a coating.Forcitation:Serbinovskiy M.Yu., Vasil'yeva N.A., Popova O.V. On complexation in process of chemical copper plating from solutions containing polyvinylpyrrolidone. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 2. P. 26-32.

Corrosion behavior of surface treated steel in liquid sodium negative electrode of liquid metal battery

While liquid metal batteries are attractive options for grid-scale energy storage applications as they have flexible siting capacities and small footprints, the compatibility between structural materials such as current collectors and negative electrode such as sodium is one of major issues for liquid metal batteries. Non-metallic elements such as carbon, oxygen, and nitrogen in the liquid sodium influence the material behaviors of the cell construction materials in the battery system. In this study, the compatibility of structural materials with sodium is investigated in high temperature liquid sodium, and electrochemical impedance spectroscopy (EIS) is used to monitor in-situ the corrosion behavior at the surface of materials in sodium. Chemical vapor deposition (CVD) coatings of SiC and Si3N4 are applied as protective barriers against dissolution and corrosion on the steel surface. The results show that CVD coating of Si compounds can delay corrosion of steel in high temperature liquid sodium comparing to the result of as-received specimens, while SiC coating is more durable than Si3N4 coating in high temperature liquid sodium.

CVD Coating of Oxide Particles for the Production of Novel Particle-Reinforced Iron-Based Metal Matrix Composites

This paper focuses on surface metallization of oxide particles by means of titanium nitride (TiN) thin films for the production of highly wear-resistant metal matrix composites (MMC) on Fe-base for wear protection applications. These powder-metallurgically produced materials consist of a metallic matrix with embedded oxide hard-particles such as alumina or zirconia. The poor wettability of these oxides by iron-base melts and the resulting weak bonding between the components lead to porous materials and weak tribomechanical properties, thus limiting the material’s application range. To counteract such problems, this paper describes a processing route in which the oxide particles are pre-metallized by application of a thin TiN coating by means of chemical vapor deposition (CVD). This surface metallization should increase the wettability and bonding behavior between the ionically bonded particles and the iron-base alloy, which should improve the mechanical and tribological properties. Therefore, a CVD device for coating ceramic particles was constructed and is described in this paper. Furthermore, coatings deposited on the ceramic sub-strates were investigated by means of RBS, SEM and XRD. In addition, the feasibility of producing metal matrix composites (MMC) by admixing the TiN-coated oxide particles with a Fe-base alloy and their further densification by supersolidus liquid-phase sintering is demonstrated.

Design of conformal, substrate-independent surface modification for controlled proteinadsorption by chemical vapor deposition (CVD)

Biofouling is a crucial consideration in a variety of applications including biosensors, biomedical implants and devices, food packaging, and industrial and marine equipment. On the other hand, the controlled adsorption of proteins is desired in certain fields such as bioassays and tissue engineering. As such, significant progress has been made in fabricating surface chemistries that are able to resist or regulate protein adsorption through the manipulation of the protein–water–surface interactions. However, a conformal, substrate-independent surface modification method is required in order to extend such chemistries to a wider range of applications including delicate substrates, nanostructured surfaces, and polymer nanotubes. Here, we review the chemical vapor deposition (CVD) of coatings to control protein adsorption. These CVD coatings can be classified into four categories: hydrophilic coatings or hydrogels, which resist protein adsorption through surface hydration; fluorinated coatings, which have especially been studied in the context of fouling release in marine environments; amphiphilic coatings involving a unique antifouling mechanism; and switchable or stimuli-responsive coatings. Many of the techniques in each group are compatible with the synthesis of surface or free-standing nanostructures, and can be easily integrated into the existing fabrication infrastructure.

Effectiveness of Low-Pressure Metal–Organic Chemical Vapor Deposition Coatings on Metal Surfaces for the Mitigation of Fouling from Heated Jet Fuel

Thin films of alumina, zirconia, tantalum oxide, and platinum were deposited on AISI304 by metal–organic chemical vapor deposition to investigate the effectiveness of these coatings in inhibiting carbon deposition and sulfide formation from thermal oxidative degradation of jet fuel. Coated AISI304 foils were heated in a laboratory scale flow reactor with a commercial jet fuel (Jet-A) flowing at 1 mL/min at a wall temperature of 350 °C and reactor pressure of 500 psig (3.4 MPa) for 5 h. Under these conditions, both liquid phase autoxidation and thermal decomposition of jet fuel contribute to carbon deposition. The surface composition of the metal oxide coatings was found by X-ray photoelectron spectroscopy. The morphology of the coating and the carbonaceous deposits formed during thermal stressing were examined by field emission scanning electron microscopy. The amount of solid carbonaceous deposits on the coated and uncoated surfaces was measured by temperature-programmed oxidation. The effectiveness of the coatings in mitigating carbon deposition was found to decrease in the following order: platinum > Ta2O5 > alumina from acetyl acetonate > ZrO2 > alumina from aluminum trisecondary butoxide > AISI304. The coatings cover the metal surface by forming a protective layer that inhibits the formation of metal sulfides from the reaction of sulfur compounds in jet fuel with iron and nickel on stainless steel and inconel surfaces, respectively. The variation in the activity of the coatings can be attributed to the interaction of oxygenated intermediates formed by autoxidation during thermal stressing with coating surfaces having different degrees of acidity.

CALCULATION AND PLOTTING OF STANDARD FREE ENERGY CHANGES AND EQUILIBRIUM CONSTANTS FOR CVD HARD COATINGS REACTIONS

CVD (chemical vapor deposition) coatings such as TiC , TiN , Al 2 O 3 and so on are widely used as tools' surface preserved materials with corrosion resistance and wear resistance. Standard Gibbs free energy changes for reactions are widely used to approximately analyze the trends of substance reactions and phase transitions in chemical reactions, metallurgy processes, materials synthesis and processing. Hard coatings and thin films can be prepared by CVD process. Accurate calculation and plotting of the standard free energy changes and equilibrium constants for CVD TiC , TiN , Al 2 O 3 coatings reactions are realized using the developed general computer program. Only inputting the basic thermodynamic data tabulated in data books into the computer program, the relationships of the standard free energy changes and equilibrium constants for most reactions with the temperatures can be gained in the same diagrams.

High energy solid particle erosion mechanisms of superhard CVD coatings

The high hardness of boron carbide (B 13C 2) and diamond make them attractive candidates for use as erosion- and abrasion-resistant coatings in applications such as valves and pumps used in the off-shore oil industry. This paper compares the dominant solid particle erosion mechanisms of boron carbide and diamond coatings produced by chemical vapour deposition (CVD), when subjected to high energy particle impacts. To generate a range of impact damage features, a variety of erodents were used with differing hardness and shape. The erosion tests were performed on a gas blast erosion rig using spherical soda-lime glass beads, angular quartz silica sand and diamond grit, at impingement velocities between 130 and 270 m s −1 and an erodent particle flux of 0.5 kg m −2 s −1. A range of techniques including optical interferometry, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), identified the damage mechanisms. For boron carbide, erosion occurred via removal of the coating through lateral/radial cracks generated by particle impacts. For the diamond coatings, the damage was in the form of stress-wave induced circumferential crack formation at delaminated regions of the coating leading to ejection of material within the cracks. The coatings were found to have a high threshold velocity for the initiation and propagation of the above damage features. Diamond was found to be highly resistant to the propagation of lateral–radial crack systems, which reflected in its superior erosion performance compared to boron carbide.

Comparison of the structure and properties of the PVD and CVD coatings deposited on nitride tool ceramics

Comprehensive structure and properties investigation results of the multi-layer, multi-component physical vapour deposition (PVD) and chemical vapour deposition (CVD) coatings developed on the Si 3N 4 nitride tool ceramics substrate are presented in the paper. The detailed results are presented of examinations carried out on the scanning and transmission electron microscopes, as well as of the mechanical properties and tribological tests of the investigated coatings. Examinations of the chemical compositions of the deposited coatings were also carried out using the X-ray energy dispersive spectrograph EDS, glow-discharge optical emission spectroscope GDOS, and using the X-ray diffractometer. Machining tests of the grey cast iron and nickel alloy were made to analyse in detail the investigated multi-edge cutting inserts. The inserts made from Si 3N 4 were coated in the PVD process with the TiN + multiTiAlSiN + TiN, TiN + TiAlSiN + TiN, TiN + TiAlSiN + AlSiTiN type multi-component coatings and in the CVD process with the coatings based on the combination of the TiC, TiN, Ti(C,N) and Al 2O 3 layers.

The Effect of Water Vapor on the Oxidation Behavior of CVD Iron-Aluminide Coatings

The oxidation behavior of iron-aluminide coatings, Fe3Al or (Fe,Ni)3Al, produced by chemical-vapor deposition (CVD) was studied in the temperature range of 700–800°C in air + 10 vol.% H2O. A typical ferritic steel, Fe–9Cr–1Mo, and an austenitic stainless steel, 304L, were coated. For both substrates, the as-deposited coating consisted of a thin (<5μm), Al-rich outer layer above a thicker (30–50 μm), lower-Al-content inner layer. In addition to coated and uncoated Fe–9Cr–1Mo and 304L, cast Fe–Al model alloys with similar Al contents (13–20 at.%) to the CVD coatings were included in the oxidation exposures for comparison. The specimens were cycled to 1000 1 hr cycles at 700°C and 500 1 hr cycles at 800°C, respectively. The CVD coating specimens showed excellent performance in the water-vapor environment at both temperatures, while the uncoated alloys were severely attacked. These results suggest that an aluminide coating can substantially improve resistance to water-vapor attack under these conditions.

Surface modifications and surface-protective coatings analyzed by means of thermal waves (invited) (abstract)

The depth profiles of the thermophysical properties of alloy systems, for example, shape memory alloys (NiTi), steel, and tool steel, can vary considerably due to rolling, surface machining, heat treatment, mechanical wear, and erosion. The same is true for coated tool steel samples, which show variations of the effective thermal depth profiles due to the effects of substrate preparation and deposition of the coatings, for example, plasma-etching, arc erosion, nitriding, chemical vapor deposition (CVD), physical vapor deposition (PVD), sputter deposition, and plasma spraying. In this work we present a large variety of measured effective thermal depth profiles. In a first step, we identify the effects of coating deposition and substrate preparation on the measured depth profiles. In a second step, we identify and try to quantify the effects of mechanical wear and erosion of both coated and uncoated surface. To this finality, the signals, which have been measured with the help of IR radiometry as a function of the modulation frequency, have been calibrated with reference signals measured for homogeneous samples of glassy carbon. The normalized amplitudes and phases have been approximated using layer models, mainly the two- and three-layer model with an opaque first layer, with respect to both the visible and the IR spectrum. Additionally, the signals measured for different coatings have been normalized against each other. By this latter calibration procedure, even smaller details and differences of coating deposition and substrate preparation can be identified, as well as the effects of wear and surface erosion. The virgin coated samples normally can well be described by the two-layer model, and the thermal transport parameters of the coatings as a whole can be determined quantitatively with rather good reliability (Ref. 1). The deviations from the two-layer model, which can be related to details of the deposition process, for example, to gradient layers or bond layers, are described by thermal diffusion times, which are orders of magnitude below the thermal diffusion time of the coating as a whole, so that they are negligible in the numerical simulation of heating or cooling processes. In many cases, however, the quantitative description based on layer models with only a small number of adjustable parameters is not possible, since the discrepancies between the reality of measurement and such a model are too large. This is the case for: (i) combined arc erosion and plasma nitriding of surfaces, which shows roughness effects with two different characteristic lengths (Ref. 2); (ii) CVD coatings, which show effects of preferred growth of some grains; (iii) strongly eroded coatings of cutting tools; and (iv) NiTi surfaces after rolling, surface machining, surface polishing, etc., where mechanical treatment can produce layer systems of the effective thermal properties with both reduced and increased effusivity values (Ref. 3).

Corrosion testing of platinum metals CVD coated titanium anodes in seawater-simulated solutions

A chemical vapour deposition (CVD) technique is widely used for the preparation of protection coatings. In the present work titanium anodes with CVD coatings of iridium, platinium and Ir—Pt composite were made The coatings were obtained by thermolysis of platinum(II) acetylacetonate and iridium(III) acetylacetonate in the oxygen or hydrogen contained atmosphere. The investigation of the samples by means of XPS showed the presence of oxide phases in the coatings. Tests of the resulting samples in the electrolysis of seawater-simulated solutions under active evolution of oxygen were conducted. Platinum coatings were found to be more stable than iridium ones, which is, to a substantial extent, due to mechanical strain at the titanium-to-coating boundary. Iridium-coated titanium foil anodes were tested in an experimental electrodialysis unit. Their service life exceeded 1 year.

Protection of coated superalloys from erosion in turbomachinery and other systems exposed to particulate flows

The design and development of high performance turbomachinery operating in an ambient with solid particles require a thorough knowledge of the fundamental phenomenon associated with particulate flows. This paper describes the overview of jet engines performance deterioration and retention. The ingestion of solid particles over period of time, will reduce the efficiency of the propulsion system, causing increased fuel consumption and thrust decrease. High pressure compressor and turbine design improvements are now developing and verifying experimentally different new ceramic coatings on superalloys such as INCO 718, Waspaloy and on SS410, subjected to gas particulate flows at high temperatures. The investigated coatings are produced by plasma spray, detonation guns, chemical vapor deposition (CVD), physical vapor deposition (PVD), and other methods. Experimental studies were conducted at the University of Cincinnati high temperature erosion wind tunnel to investigate the erosion behavior of coatings exposed to different types of solid particles. Some of the following coatings were evaluated: rhodium platinum aluminized, SDG-2207 (super D-gun product), CVD coatings, including TiC, TiN, Al 2O 3, and PVD coatings. The erosive wear of the samples was studied experimentally by exposing them to particle laden flow at velocities from 180 to 305 m s −1, temperatures from ambient to 815°C and impingement angles from 15° to 90°.

Rapid thermal processing of TiN coatings deposited by chemical and physical vapor deposition using a low-energy, high-current electron beam: Microstructural studies and properties

Monolithic TiN coatings deposited onto cemented carbide cutting tool inserts coated by chemical vapor deposition (CVD) or physical vapor deposition (PVD) methods, respectively, were subjected to pulsed intense electron beam treatments in the energy range 3 to 5 J·cm−2. The temperature profiles for this rapid thermal processing (RTP) covered the range between fusion of the cobalt binder in the carbide to surface fusion of the TiN coatings. The treatment caused extensive cracking in all coatings, removed the atomic level defects, vacancies and dislocations, and the residual stress in the PVD coatings, but caused little change in the CVD coatings. There was some nitorgen loss very close to the surface but no change in the stoichiometry of the bulk of the nitride. In contrast, no changes were found in the carbide substrate below the PVD coatings, but microscopic changes were found immediately below the surface in the carbide under the CVD coatings. Steel turning tests suggest that treatment of the PVD coatings at the lowest power used, 3 J·cm−2, reduced the flank wear by a factor of 2 but had no effect on any of the CVD coatings.