TiC Coatings Research Articles

Wear Resistance of Stellite-6/TiC Coating on Stainless Steel 316L Produced by Laser Cladding Process

Wear Resistance of Stellite-6/TiC Coating on Stainless Steel 316L Produced by Laser Cladding Process

Development of TaC-based transition metal carbide superlattices via compound target magnetron sputtering

Transition metal carbides belong to ultra-high temperature ceramics and are particularly valued for their high thermal and mechanical stability as well as melting points of even above 4000 °C. However, a considerable limitation of these materials is their high inherent brittleness. Inspired by the success of nanolayered superlattice architecture—shown to enhance both hardness and toughness of transition metal (TM) nitrides—we developed superlattice films with TM carbides. Among these, density functional theory calculations suggest TaC/HfC and TiC/TaC to have a similar shear modulus mismatch of 23 and 19 GPa, but a different lattice parameter mismatch of 4.2 and 2.4%, respectively. Detailed transmission electron microscopy and X-ray diffraction show a pronounced superlattice structure for TiC/TaC with nominal bilayer periods Λnom of 2, 6, and 10 nm. Contrary, the TaC/HfC showed a more solid solution like characteristic for Λnom = 2 nm, and a clear superlattice structure for Λnom = 6 and 10 nmjap. While the hardness of the TaC/HfC coatings is between those of their constituents TaC (33.3 ± 1.9 GPa) and HfC (37.4 ± 3.2 GPa), the TiC/TaC superlattices outperform their constituents and clearly show a superlattice-effect with a peak of 44.1 ± 3.4 GPa at Λnom = 2 nm (TiC has 37.6 ± 3.1 GPa). Also the qualitative fracture behavior investigation with 450-mN-loaded cube corner indentation yield the TiC/TaC superlattices to be superior to the TaC/HfC as well as the monolithically prepared TiC, TaC, and HfC coatings.

Effect of Chlorine Salts on TiC Coating Morphology and Bonding Strength of Diamond Surface in Molten Salt Reaction

To obtain a high-quality TiC coating on the diamond (D) surface and improve the interfacial properties of metal matrix composites, the optimized molten salt method is used to prepare TiC coatings on the D surface. The effects of NaCl, KCl, and NaCl–KCl molten salts on the uniformity, surface morphology, composition, and bonding ability of TiC coatings are investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction, and cold–hot cycling experiments. The results show that the boiling and pickling processes after the molten salt reaction can effectively remove the residual chloride salts and Ti powders to obtain clean TiC-coated D. The TiC particles of the coating surfaces prepared by NaCl and KCl molten salts are finer and more uniform, which is due to their higher melting points and shorter real reaction time compared with NaCl–KCl mixed salts. The TiC coating prepared by KCl has the best bonding ability and can withstand 50 times as many cold–hot cycles due to its uniform fine deposition particles and appropriate thickness. And, during cold–hot cycles, it can be found that the TiC coating cracking and shedding occur primarily at the edges and corners of the D with internal thermal stress concentration.

In situ synthesis of titanium carbide coating on foam titanium by molten salt electrolysis

In this study, TiC coatings were formed on titanium foam by the carbon precipitation reaction (CO32−+4e− = C+3 O2−) during molten salt electrolysis, and the effects of the pre-oxidation process, electrolysis time and molten salt composition on the formation of TiC coatings were explored. The results show that the pre-formed oxide layer on the titanium foam surface can promote the formation of TiC coating. Prolonging the electrolysis time can increase the thickness of the TiC coating, but a long time will cause the excessive growth of TiC particles and the falling off the coating. Reducing the surface tension of molten salt can promote the diffusion of CO32− in the titanium foam, and TiC coating can also be formed inside foam titanium. When there is TiC coating on the surface of foam titanium, the hardness increased from 144.5 HV to 795.6 HV, and the wear amount is reduced by about 86%.

Microstructure Evolution and Mechanical Properties of TiC Coating over Inconel 625 Obtained by Vacuum Electron Beam Surface Alloying

Inconel 625 nickel-base alloy was modified by electron beam surface alloying (EBSA) with TiC as the coating at different scanning speeds (80 mm/min, 100 mm/min, and 120 mm/min). Its microstructure evolution and friction and wear evolution were characterized using electron backscatter diffraction (EBSD), a microhardness tester, and a friction and wear tester (RTEC). The results indicated that the FCC phase in the microstructure of the Inconel 625 nickel-base alloy is island-shaped after EBSA. At different scanning speeds, the austenitic texture types will eventually form primarily S-texture accompanied by Goss texture and Brass texture of varying strengths. With an increase in scanning speed, the surface hardness of nickel-base alloys decreases. The highest surface hardness was 457 HB at 80 mm/min, and the surface hardness was 1.936 times higher than that of the base material. With an increase in scanning speed, the wear resistance of the nickel-base alloy plates decreased gradually. At the scanning speed of 80 mm/min, the wear volume and wear rate were the lowest, which were 0.9131 mm3 and 3.0437, respectively, and the wear rate decreased by 30.48%.

Effect of carbon content on the structural, mechanical and corrosion properties of TiC films deposited using a HiPIMS discharge

TiCx thin films have been deposited on steel substrates using High Power Impulse Magnetron Sputtering (HiPIMS) under Ar-C2H2 atmosphere. The effect of varying the acetylene content on the deposition process, and on the structural, mechanical and corrosion resistance properties was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), nanoindentation, scratch testing, potentiodynamic polarization, electrochemical impedance measurements (EIS), and salt spray. This study showed that an increase of the carbon ratio affected the deposited TiC coatings morphology and mechanical properties, with hardness values reaching up to 25 GPa. The near-stoichiometric coating exhibited the highest hardness while maintaining improved toughness, resistance to plastic deformation and resistance against crack propagation thanks to their nanocomposite structure. In contrast, corrosion tests showed that the understoichiometric coatings exhibited the best corrosion resistance in a 3.5 % wt NaCl medium. The drop of the corrosion performances of TiCx coatings deposited at higher acetylene flow rate was linked to a growth-related defects extending throughout the coating thickness, formed due to micro-droplet ejection from the target as evidenced by SEM analysis.

The Effect of the Displacement Amplitude on the Fretting Wear of GCr15 Steel with a TiC Coating.

In the present paper, the effect of mechanical ball milling time on the fretting wear of GCr15 steel balls at different displacement amplitudes is investigated. TiC powder coating was fabricated on the surface of GCr15 steel balls using various process times, and the fretting wear tests were conducted on an AISI 52100 steel disk with the applied force of 80 N. Additionally, various displacement amplitudes (10 μm, 20 μm, and 60 μm) were selected. Specimen attributes and wear scars were characterized using an inverted metallographic microscope, a microhardness tester, an X-ray diffractometry analyzer, a white light interferometer, and a scanning electron microscope. The results showed that thick and continuous coatings could be obtained at the milling time of 18 h. The specimens processed for a longer milling time demonstrated better fretting wear resistance, which we attribute to higher microhardness of the surface layer. The coefficient of friction and wear volume of specimens at each different displacement amplitude significantly decreased with increasing milling time. As the displacement amplitude increased, the three fretting states were: partial slip coordinated by elastic deformation; partial slip state coordinated by plastic deformation; and gross slip condition. Our observations indicate that mechanical ball milling could be an efficient approach to improve the fretting wear resistance of GCr15 steel balls.

Effect of carbon fibers crystallinity on the formation and growth of TiC coating in molten salt

To improve the application of molten salt method in carbon fibers (CFs) surface modification, the work explores the effect of the CFs-itself crystallinity on the formation and growth mechanism of TiC coating in the molten salt reaction. Three different types of CFs were used to prepare TiC coatings at 850°C, and the formation and growth mechanisms were studied. The results showed that CFs surface defects could preferentially initiate nucleation and cause inhomogeneity of TiC particles in the initial stage of TiC coating formation. The CFs surface with high crystallinity could obtain a finer and more uniform TiC coating because the growth rate of TiC particles is slower and the particles do not accumulate with each other during the coating growth. At the same time, the growth rate of TiC coating decreased with increasing CFs crystallinity during the TiC coating growth, which reason is that CFs with higher crystallinity require more activation energies of carbon atom counter diffusion. Therefore, the surface of CFs with higher crystallinity and fewer surface defects is easier to obtain a uniform and particle size TiC coating during the molten salt reaction.

Low voltage environmentally friendly plasma electrolytic oxidation process for titanium alloys

Plasma electrolytic oxidation (PEO) is a surface-treatment process extensively used to protect the surfaces of light metals such as Mg, Al, and Ti. Here, we report an environmentally friendly PEO process that uses nitrogen-containing electrolytes and low voltages (120 V) to form ~ 12 micron thick, uniform, adherent and porous oxide coatings on T1 titanium alloy surfaces. We evaluated the influence of nitrogenation by comparing the coatings to alloys treated in PEO baths without nitrogen-containing compounds. Both sets of samples exhibited basalt-like morphologies with distinct variation in the pore structures. The composition analyses showed that the coatings were primarily composites of titanium oxides and silicates. The T1 Ti alloys treated with nitrogen-containing electrolytes also contained TiC and TiN. This is the first ever report of producing TixOy, Ti–Si–O, TiC, and TiN composite coatings using a single PEO bath without carbide/nitride nanoparticles. The bandgaps of the coatings suggested visible light functionality. The use of nitrogen-based compounds in the PEO baths improved the hardness of the oxide layers but introduced stress-induced cracking which are potentially responsible for the reduction in corrosion resistance of the nitride and carbide containing coatings.

Performance of Ni-Based Coatings with Various Additives Fabricated by Cold Gas Spraying

The complexity of the operating conditions in oil fields requires the development and use of materials with unique properties. This paper presents the study results for nickel-based coatings fabricated by cold gas spraying. In this study, compositions based on Ni, Ni-Cu, Ni-Zn, Ni-Al2O3/TiC coatings applied to low-alloyed steel bases were investigated. Corrosion resistance was studied by means of electrochemical autoclave testing in simulated oilfield conditions. Hydroabrasive resistance was studied using a unique testing bench. Scanning electron microscopy mappings, microhardness testing, and adhesion testing were used to correlate the results of the tests with the structure, continuity, and porosity of the studied coatings. All the studied coating specimens had a sufficiently high adhesion. The Ni-Zn coating exhibited the lowest corrosion resistance and high hydroabrasive resistance. The Ni-Cu coatings exhibited a high degree of corrosion. The Al2O3/TiC additives gave ambiguous results with respect to the studied properties. Thicknesses of 40–60 microns provided acceptable performance for the studied coatings. Thus, varying the chemical composition the thickness of coatings allows optimal qualities to be obtained for Ni-based coatings made by cold gas spraying for use in the oil and gas industry.

Microstructure, Growth Kinetics, and Wear and Corrosion Properties of Tic Coatings on Pure Titanium by Carburizing

Microstructure, Growth Kinetics, and Wear and Corrosion Properties of Tic Coatings on Pure Titanium by Carburizing

Investigating the Effect of Tic Coating Layer on the Surface Roughness of Tungsten Carbide Cutting Tools Using Taguchi Design

In this study, external longitudinal turning operation was performed on (AISI 1020) steel to examine the influences of coating of the cutting tool on the machined surface roughness. The cutting tools used were coated and uncoated cemented carbide inserts. The tests are performed at four spindle speeds (80, 315, 500, and 800) rpm, at each of which two feed rates (0.2 and 0.5mm/rev) and two depth of cut (0.5 and 0.7mm) were used. Taguchi design of experiments (DOE) with a designed mathematical predictive model was used to investigate the effect of the coating layer and determine the machining conditions for minimum surface roughness. Accordingly, a suitable mixed orthogonal array L16 (3*4) was selected. The results showed that the surface roughness produced by using TiC coated inserts for identical machining conditions was lower than that produced due to uncoated tool by 41% to 53%. Regression analysis showed that the non-linear quadratic polynomial equation appears to be more suitable for representing the relation of spindle speed, feed rate, and depth of cut with the surface roughness. Taguchi method and the designed mathematical model had been used to predict the optimal cutting conditions. A confirmation test for the obtained results verified that the designed Taguchi experiments and the designed model successfully investigated the effect of the coating on the surface roughness. Data fit ver.9 and Mtb14 software had been employed to achieve the object of the presented work.

Wear and surface finish studies on CVD coated tungsten carbide indexable inserts

The present work aims at studying of the different types of wear occurring in cemented carbide indexable inserts. Chemical Vapour Deposition (CVD) coated tungsten carbide inserts were selected for the experimentation. Coating was brought about by vapor phase deposition process (CVD). TiN, TiC & Al2O3 coated grades were considered, as they are presently in wide commercial applications. Experiments have been conducted to study the flank wear, crater wear, nose deformation, built up edge formation etc., using R&D facilities at Kennametal India Ltd., Bengaluru. Experiments were conducted to compare surface finish at different feeds and different machining time. Studies indicated that the wear development and wear progression is very much slower in coated grades compared to uncoated grades. Surface finish is comparatively good in case of coated grades which are inferred using SEM. At low cutting speeds the existence of TiC Coating increases the life of the tool. Diffusion occurs as the cutting speed is increased, resulting in a high temperature, necessitating the use of a glaze that is both thermally and chemically stable (Al2O3). Wear analysis is an essential part of cutting tool application in order to assess the performance of coated layers as well as coating process. To measure the wear resistance of the material Pin on disc method is used. Wear analysis were carried out to study all the three types of wear. Experiments were conducted to record flank wear, crater wear, and Built-Up-Edge (BUE) in plain turning of EN8 alloy steel in CNC high powered lathe. Studies were extended to compare tool life of coated grades with uncoated grades. The results of the different stages of the experiments were recorded and discussed in the current study.

Micromechanical behaviour and wear resistance of hybrid plasma-sprayed TiC reinforced Tribaloy-400

Cobalt-based alloys such as Tribaloy-400 are known for their sliding wear resistance at room as well as elevated temperature. However, further enhancement in terms of hardness and wear resistance could be achieved by creating metal matrix composites reinforced by ceramic particles. For this purpose, Tribaloy-400 based coatings were deposited with the addition of different amounts of TiC reinforcement (≈25 vol%, ≈40 vol%, ≈60 vol%) through a “hybrid” plasma spray process , using a dry Tribaloy-400 powder with 10–45 μm particle size and a water-based TiC suspension (d 50 = 2.2 μm). Pure Tribaloy and pure TiC coatings were employed for comparison. During spraying, TiC was partly oxidized but could nonetheless be embedded between the bigger Tribaloy-400 lamellae. Specifically, the coating containing ≈ 25 vol% TiC shows a homogeneous microstructure, whilst greater amounts of hard phase lead to some agglomeration. Accordingly, the coating with 25 vol% TiC exhibits a good combination of hardness and toughness (the latter being assessed by scratch testing) and low sliding wear rates of ≈10 −5 –10 −6 mm 3 /(N·m) from room temperature up to 700 °C in ball-on-disc tests against an Al 2 O 3 counterbody. At room temperature, the tribological behaviour of the coatings is controlled by abrasive grooving and spallation due to surface fatigue. With increasing temperature, tribochemical phenomena take on an ever-increasing role and, at 700 °C, a uniform, oxide-based tribofilm is developed, so that the wear rates are often lower than are recorded at 400 °C. • Composite coatings are obtained by hybrid plasma spraying of a TiC suspension and dry Tribaloy-400. • The coatings contained Ti-oxycarbides because TiC was partly oxidized during spraying. • The hard phase tends to cluster when its content is >25 vol%. • The coating with ≈25 vol% hard phase had sliding wear rates of 10 −6 –10 −5 mm 3 /(N·m) from room temperature to 700 °C. • Wear mechanisms change from abrasion and fatigue to tribo-oxidation as temperature increases.

Microstructure, tribological performances, and wear mechanisms of laser-cladded TiC-reinforced NiMo coatings under grease-lubrication condition

Abstract NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings were prepared on GCr15 steel by laser cladding (LC). The microstructure and the phases of the obtained coatings were analyzed using ultra-depth-of-field microscopy (UDFM) and X-ray diffraction (XRD), respectively. A ball-on-disk wear test was used to analyze the friction-wear performance of the substrate and the NiMo-TiC coatings under grease-lubrication condition. The results show that the grain shape of NiMo-TiC coatings is dendritic. The wear resistance of NiMo-TiC coatings is improved by the addition of TiC, and the depths of the worn tracks on the substrate and on the NiMo-5%TiC, NiMo-15%TiC, and NiMo-25%TiC coatings are 4.183 μm, 2.164 μm, 1.882 μm, and 1.246 μm, respectively, and the corresponding wear rates are 72.25 μm3/s/N, 32.00 μm3/s/N, 18.10 μm3/s/N, and 7.99 μm3/s/N, respectively; this shows that the NiMo-25%TiC coating has the highest wear resistance among the three kinds of coatings. The wear mechanism of NiMo-TiC coatings is abrasive wear, and the addition of TiC plays a role in resisting wear during the friction process.

Effect of Low-Energy Nitrogen Ion Implantation on Friction and Wear Properties of Ion-Plated TiC Coating

To further improve the performance of the coated tools, we investigated the effects of low-energy nitrogen ion implantation on surface structure and wear resistance for TiC coatings deposited by ion plating. In this experiment, an implantation energy of 40 keV and a dose of 2 × 1017 to 1 × 1018 (ions/cm2) were used to implant N ions into the TiC coatings. The results indicate that the surface roughness of the coating increases first and then decreases with the increase of ion implantation dose. After ion implantation, the surface of the coating will soften and reduce the hardness, and the production of TiN phase will gradually increase the hardness. Nitrogen ion implantation can reduce the friction coefficient of the TiC coating and improve the friction performance. In terms of wear resistance, the coating with an implant dose of 1×1018 ions/cm2 has the greatest improvement in wear resistance. Tribological analysis shows that the improvement in the performance of TiC coatings implanted with N ions is mainly due to the effect of the lubricating implanted layer. The implanted layer mainly exists in the form of amorphous TiC, TiN phase, and sp2C–C phase.

Metallic Material Selection and Prospective Surface Treatments for Proton Exchange Membrane Fuel Cell Bipolar Plates-A Review.

The aim of this review is to summarize the possibilities of replacing graphite bipolar plates in fuel-cells. The review is mostly focused on metallic bipolar plates, which benefit from many properties required for fuel cells, viz. good mechanical properties, thermal and electrical conductivity, availability, and others. The main disadvantage of metals is that their corrosion resistance in the fuel-cell environment originates from the formation of a passive layer, which significantly increases interfacial contact resistance. Suitable coating systems prepared by a proper deposition method are eventually able to compensate for this disadvantage and make the replacement of graphite bipolar plates possible. This review compares coatings, materials, and deposition methods based on electrochemical measurements and contact resistance properties with respect to achieving appropriate parameters established by the DOE as objectives for 2020. An extraordinary number of studies have been performed, but only a minority of them provided promising results. One of these is the nanocrystalline β-Nb2N coating on AISI 430, prepared by the disproportionation reaction of Nb(IV) in molten salt, which satisfied the DOE 2020 objectives in terms of corrosion resistance and interfacial contact resistance. From other studies, TiN, CrN, NbC, TiC, or amorphous carbon-based coatings seem to be promising. This paper is novel in extracting important aspects for future studies and methods for testing the properties of metallic materials and factors affecting monitoring characteristics and parameters.

Effect of concentration of TiC on the properties of pulse electrodeposited Ni–P–TiC nanocomposite coatings

Ni–P/TiC nanocomposite coatings, including different concentrations of TiC nanoparticles (TCNPs) were developed on HSLA (high strength low alloy steel) substrates through the pulse electrodeposition (PED) process. The prepared coatings' structural, compositional, mechanical, wear, and electrochemical properties were accomplished, applying numerous characterizing techniques. The surface morphologies show the coatings are uniform, and compact, which appears flawless. An increase in the mechanical response of Ni–P/TiC is noticed with an increasing amount of TCNPs into the Ni–P matrix, attaining its highest values (720 Hv microhardness, 22.22 GPa modulus, 7.26 kN/m stiffness), and the lowest wear rate (ws) of 0.87 μ gm/Nm) for Ni–P/0.75TiC composition. The improvement in mechanical behavior can be attributed to grain refinement and dispersion hardening effect. Electrochemical Impedance Spectroscopy (EIS) and Potentiodynamic plots reveal a substantial increment in Ni–P coatings' corrosion resistance by successively incorporating TCNPs. As a comparison, Ni–P/0.75TiC coatings demonstrate the highest corrosion protection requirement efficiency (PE) of 94% in saline water. The promising performance of Ni–P/0.75TiC coating can be credited to forming a compact structure containing inactive TCNPs in the Ni–P matrix.

Effects of Process Parameters on Geometrical Characteristics and Microstructure of TiC Particle‐Reinforced Co50 Alloy by Laser Cladding

Laser cladding of Co50 alloy coating and Co50 composite coatings doped with 10, 20, and 30 wt.% TiC particles was performed on the H13 steel surface. The effects of TiC concentration on the phase composition, microstructure, and microhardness of the coatings were studied. The results indicated that, in 10% TiC coating, the “bright band” is a quite flat‐growth tissue, while with 20% TiC, the “white bright band” contains a large amount of black TiC particles. The composite coating Co50, 10% TiC, and 20% TiC samples can clearly distinguish the cladding zone, bonding zone, and heat‐affected zone, and a good metallurgical bond is formed between the coating and the substrate. The 30% TiC coating and the substrate are not well bonded, which is attributed to the high TiC content in the coating; however, it has the best surface morphology, and there is no porosity on the surface. 10% TiC coatings have poor surface quality, show a spraying material phenomenon on two side edges which is quite serious, and a lot of porosity on the surface of the coating. In addition, 10% TiC coating includes the original TiC particles and primary TiC particles that are precipitated in situ from the liquid phase during solidification; 20% TiC coating indicates a large amount of TiC in the form of cross petals and twigs, and the figure points out that TiC exists like a large number of diffusely distributed spherical structures in the 30% TiC coating. The coatings of TiC/Co composite with less than 20% TiC showed good metallurgical bonding characteristics with the H13 steel surface.

Titanium-Doped Powder Coatings with a TiN Layer on 9KhS Steel and VK8 Hardmetal Substrates

The phase and chemical compositions, structure, and properties of titanium/aluminum-doped coatings with a TiN layer on 9KhS steel and VK8 hardmetal substrates were studied. A TiN layer 5.0–5.5 μm thick was applied by the physical vapor deposition method. The alloys were doped with titanium and aluminum in fusible containers in a mixture of powders consisting (wt.%) of 40.0 Ti, 5.0 Al, 5.0 Al2O3, and 5 NH4Cl at 1050°C for 4 h. Multilayer coatings including Al2O3, Fe2Ti4O, TiC, and TiN formed on the 9KhS substrate and Al2O3, TiAlCO2, TiC, and TiN coatings on the hardmetal substrate. The TiN layer completely inhibited the penetration of aluminum into the 9KhS substrate and of aluminum and oxygen into the VK8 hardmetal substrate. The coating on 9KhS steel had no Feα(Al) layer, and the coating on VK8 hardmetal had no area containing aluminum and oxygen. Individual layers in the coatings exhibited high microhardness: 35.6 GPa for the TiC layer on 9KhS steel, 29.0 GPa for the TiC layer on VK8 hardmetal, and 23.4–23.6 GPa for the TiN layer on both substrates. The cross-sectional structure of the coatings was virtually porousless, showing good adhesion between the individual layers and the substrate, being characteristic of diffusionhardened coatings. The wear resistance of the coated 9KhS steel was 6.9 times higher than that of the uncoated steel in dry sliding friction conditions. The coated 9KhS steel showed an extreme dependence of the wear on the sliding velocity. Mechanically fastened indexable hardmetal cutting tools with coatings demonstrated 8.3 times higher resistance than uncoated tools tested by 40Kh13 steel cutting. The coatings developed can substantially increase the performance of 9KhS steel and VK8 hardmetal tools.