TiC Coatings Research Articles

钛合金表面激光熔覆Ti C复合涂层的设计

钛合金表面激光熔覆Ti C复合涂层的设计

Effect of a TiC Coating on the Stress-Strain State of a Plate of a High-Density Nitride Ceramic Under Nonsteady Thermoelastic Conditions

An original method is presented to obtain relations which describe how the thickness and thermal conductivity of a TiC coating are related to the temperatures, displacements, and stresses in a nitride ceramic plate under nonsteady thermoelastic conditions. It is shown that the stress-strain state of parts made of high-density ceramics can be controlled under such conditions by the application of coatings.

Properties of TiC Coating by Pulsed DC PACVD

In the PACVD technique, temperature and gas flow rate are two important parameters affecting the coating characteristics. Effect of these parameters on mechanical behaviors of TiC coating that was deposited on hot work tool steel (H13) was investigated in this paper. We analyzed TiC coating composition and structure with grazing incidence X-ray diffraction (GIXRD) and Fourier transformation infrared spectroscopy (FTIR). The mechanical properties of the coatings, such as microhardness, wear resistance, and surface roughness, were studied with Knoop hardness indentation, pin on disk wear tests, and atomic force microscopy, respectively. When the deposition temperature decreased from 490°C to 450°C and the CH4 to TiCl4 flow rate ratio was also increased from 1.5 to 6, TiC coating color changed from dark gray to silver. The best mechanical properties such as a high hardness (27 GPa), wear resistance, and low surface roughness were related to the coating that was deposited at 450°C.

Fabrication of Titanium-Based Hard Coatings by Atmospheric Microplasma-Metal Organic Chemical Vapor Deposition Using Titanium Tetraisopropoxide

The atmospheric microplasma metal organic chemical vapor deposition (AP-MOCVD) using titanium (IV) tetraisopropoxide (TTIP) as a metal alkoxide titanium source was investigated for depositing TiC and TiN hard coatings on stainless steel rods for improving the tool life of electroplated diamond tools. The components and morphology of the coating deposited by microplasma AP-MOCVD with several gas sources and different processes was observed and analyzed. The titanium-based hard coatings composed of TiC, TiN, and TiO2 was successfully obtained by microplasma AP-MOCVD using TTIP as a metal alkoxide titanium source with mixed gases (CH4, N2, H2, and Ar). For the fabrication of titanium-based coatings (TiC, TiN) by microplasma AP-MOCVD, it is important that the carbon and oxygen content, which are components of TTIP, are reduced. The addition of hydrogen gas in the microplasma AP-MOCVD process, followed by nitriding effectively reduces the carbon and oxygen content in the coating.

Effect of Powder Particle Size and Substrate Hardening on the Formation of Nanostructured TiC Coating on AISI-D2 Steel by Mechanical Milling

In this study TiC coating was formed on AISI-D2 steel by mechanical milling. In this regard, steel sample, balls and the powder were placed within a milling vial. Ball milling were carried out with annealed and quench-tempered samples using TiC powder having particle sizes of 44 and 200 μm for 5, 10, 15, 20, 50 and 100 h. During milling treatment, sample surface was exposed to high energy collisions and powder particles trapped between balls and sample adhered to the surface through cold welding. It was shown that the thickness and the structure of the coating depended on powder particle size; hardness and milling time. The thickness of the coating increased at first and decreased thereafter with milling time. The results showed that the substrate hardening decreased the thickness of the coating. Scanning Electron Microscopy (SEM) was employed to investigate the structural characteristics of the coatings. X-ray Diffraction (XRD) analysis was also conducted to determine the kind of phases in the coating. SEM investigations showed that the greatest thickness of the coating was reached after 20 h of milling. Furthermore, no new phases were detected in the XRD results after 100 h. It was shown that the thickness and hardness of coatings with coarse particle size were lower than that of the other. It was revealed that lattice parameter of TiC coating increased with milling time.

Effect of titanium and tungsten carbide on the formation of the structure and properties of composite coatings. Part 3: wear resistance of steel R6M5–(WC+TiC)/TiC coatings

The results of analysis of the relative abrasion wear resistance of composite coatings based on a high-speed tool steel are presented. It is shown that the R6M5 steel–(TiC+WC) coating, with the initial surfacing mixture containing 20% of the hardening phase (5% TiC+15% WC), has the highest wear resistance and does not require additional heat treatment.

INTERACTION STUDIES OF CERAMIC VACUUM PLASMA SPRAYING FOR THE MELTING CRUCIBLE MATERIALS

Candidate coating materials for re-usable metallic nuclear fuel crucibles, TaC, TiC, ZrC, ZrO₂, and Y₂O₃, were plasmasprayed onto a niobium substrate. The microstructure of the plasma-sprayed coatings and thermal cycling behavior were characterized, and U-Zr melt interaction studies were carried out. The TaC and Y₂O₃ coating layers had a uniform thickness, and high density with only a few small closed pores showing good consolidation, while the ZrC, TiC, and ZrO₂ coatings were not well consolidated with a considerable amount of porosity. Thermal cycling tests showed that the adhesion of the TiC, ZrC, and ZrO₂ coating layers with niobium was relatively weak compared to the TaC and Y₂O₃ coatings. The TaC and Y2O₃ coatings had better cycling characteristics with no interconnected cracks. In the interaction studies, ZrC and ZrO₂ coated rods showed significant degradations after exposure to U-10 wt.% Zr melt at 1600℃ for 15 min., but TaC, TiC, and Y₂O₃ coatings showed good compatibility with U-Zr melt.

Effect of titanium and tungsten carbide on the formation of the structure and properties of composite coatings. Part 2: Structural and phase composition of R6M5 steel – TiC coatings

The results of investigation of the special features of the formation of the structural and phase composition of R6M5 steel – TiC composite coatings in relation to the content of titanium carbide are presented. It is shown that the amount of retained austenite in the hardened layer does not exceed 5% of the total volume of the matrix already after adding 5% titanium carbide. The mean size and the volume fraction of the titanium carbide particles decreased in analysis of the structure from top to the bottom of the deposit.

Wear monitoring of single point cutting tool using acoustic emission techniques

This paper examines the flank and crater wear characteristics of coated carbide tool inserts during dry turning of steel workpieces. A brief review of tool wear mechanisms is presented together with new evidence showing that wear of the TiC layer on both flank and rake faces is dominated by discrete plastic deformation, which causes the coating to be worn through to the underlying carbide substrate when machining at high cutting speeds and feed rates. Wear also occurs as a result of abrasion, as well as cracking and attrition, with the latter leading to the wearing through the coating on the rake face under low speed conditions. When moderate speeds and feeds are used, the coating remains intact throughout the duration of testing. Wear mechanism maps linking the observed wear mechanisms to machining conditions are presented for the first time. These maps demonstrate clearly that transitions from one dominant wear mechanism to another may be related to variations in measured tool wear rates. Comparisons of the present wear maps with similar maps for uncoated carbide tools show that TiC coatings dramatically expand the range of machining conditions under which acceptable rates of tool wear might be experienced. However, the extent of improvement brought about by the coatings depends strongly on the cutting conditions, with the greatest benefits being seen at higher cutting speeds and feed rates. Among these methods, tool condition monitoring using Acoustic Techniques (AET) is an emerging one. Hence, the present work was carried out to study the stability, applicability and relative sensitivity of AET in tool condition monitoring in turning.

Preparation of porous TiC/C ceramics using wooden template in molten salt media

Biomorphic TiC/C ceramics with a wood-like structure were synthesised using a template fabricated from wood. TiC coatings were obtained on the surface of a carbon template via reacting it with Ti powder in a mixture of a molten KF–KCl binary salt under an argon atmosphere. Phase composition and microstructure of the TiC/C ceramics were characterised by X-ray diffraction, scanning electron microscopy and X-ray spectroscopy. The pore size distribution within the porous TiC/C ceramics was investigated using automatic mercury porosimetery. The results demonstrated that Ti powder reacted with the cellular carbon walls of the wood to form TiC coatings at 700–1000°C. Furthermore, the synthesised TiC/C ceramic retained the morphology of the carbon template, indicating that the formation of the carbon template played a dominant role in the formation of the TiC/C ceramic possessing a highly microporous structure.

TiC Coating on Titanium by Carbonization Reaction Using Spark Plasma Sintering

Hard TiC coating layer is formed on commercially pure titanium by heat treatment in a spark plasma sintering (SPS) mold filled with graphite powder. In case of heat treatment at 1243K for 3600 s, the obtained thickness of the coating layer is about 10 μm and almost uniform. This coating itself consists of TiC and graphite, and there is no titanium oxide detected by X-ray diffractometer (XRD). Vickers hardness tests have revealed that the hardness of titanium coating is 1600HV, which is much higher than that of the titanium substrate (130HV). The hard TiC coating on titanium is considered to be advantageous when applied to load bearing parts of hard tissue replacements. The growth behavior of TiC is parabolic with an activation energy of 218.6 kJ/mol. This value is close to the activation energy of carbon diffusion in TiC. Therefore, the growth rate of TiC is rate-controlled by inward diffusion of carbon in the TiC phase. [doi:10.2320/matertrans.L-M2013829]

Novel Synthesis and Characterization of Titanium Carbide Coatings on Graphite Flakes

Titanium carbide coatings were synthesized by reacting with titanium powders in NaF-NaCl based salt on surface of graphite at 1100-1400 °C in argon (Ar). The effect of temperature of heat treatment on TiC coatings properties was studied. Phase composition and microstructure of the TiC coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectroscopy (EDS). The “template-growth” mechanism plays a dominant role in the coating formation process.

Determination of Surface Qualities on Inclined Surface Machining with Acoustic Sound Pressure

Die parts used in automotive and aviation industry have complicated surfaces that require multiaxis machining. In machining of inclined surfaces with ball-end milling, the process is of great significance for its correctness and accuracy. In this study, Acoustic Sound Pressure (ASP) generated during the machining of a workpiece at a vertical machining centre has been measured. The experiments have been conducted in association with cutting velocity, feed rate and step over parameters determined by using different surface forms and different cutter path strategies. Therefore, the aim of this study is to understand the relationships between the generated sound signals and surface roughness in the machining of inclined concave and convex surfaces. In the experiments, the workpiece material of EN X40CrMoV5-1 hot work tool steel, which is commonly used in the related die industry, has been chosen. The ball end mills with two indexable inserts with three different coatings of TiC, TiN, and TiAlN have been used. The results show that there is a rise at the value of surface roughness with a rise at the value of acoustic sound pressure and that surface roughness could be figured out with acoustic sound pressure level.

Corrosion behavior of HVOF sprayed coatings of NiTiC and Ni(Ti,W)C SHS produced composite powders and Ni + TiC mixed powder

In this research, the corrosion behavior of different types of (NiTiC) coatings produced by high velocity oxy‐fuel (HVOF) technique was studied. NiTiC and Ni(Ti,W)C composite powders were produced by self‐propagation high temperature synthesis (SHS). These powders as feedstock were thermally sprayed on steel substrates in comparison with a conventional powder mixture of Ni + TiC. The microstructures of the produced coatings were characterized using SEM micrographs. The presence of different phases in the microstructure was investigated using EDS analysis and XRD patterns. Also, the behavior of the coatings against a corrosive media was studied using Tafel polarization tests. The results show that the NiTiC and Ni(WTi)C coatings exhibited better corrosion resistance than conventional Ni + TiC mixture coating due to the increment of the homogeneity of the structure and the decrement of the porosity level. In addition, the presence of W in the microstructure of Ni(WTi)C coating provided the least pitting and highest general corrosion.

Low Temperature TiC Coating Process by Plasma Enhanced Chemical Vapor Deposition

not Available.

Microstructure and Tribological Property of TiC-Mo Composite Coating Prepared by Vacuum Plasma Spraying

TiC-based composite coating using Mo as an additive has been fabricated by vacuum plasma-spraying, and then the phase composition and microstructure of TiC-Mo composite coating were investigated. Wear resistance of the TiC-Mo composite coating was comparatively studied with pure TiC coating. The experimental results showed that the microstructure of the TiC-Mo composite coating was relatively homogeneous and compact, exhibiting typical lamellar structure of plasma-sprayed coating. Orientated columnar grains of TiC can be found in the composite coating, and a (Ti, Mo)C transition phase was also observed. Due to the formation of (Ti, Mo)C transition phase, strong interface between TiC and Mo splats was obtained, which positively influenced the wear performance of the composite coating. As compared with pure TiC coating, the TiC-Mo composite coating exhibited improved wear resistance both at low and high loads. Wear mechanisms for the TiC coatings have been changed by adding Mo element.

Effect of Manganese on Titanium Thin Films Adhesion Deposited on Steel Substrates

The mainly property of thin solid films technologies is their adhesion to the substrates. Because of its good wear resistance and its low coefficient of friction against steel, TiC is an attractive coating material for wear applications such as bearing components. The adhesion of TiC coatings, however suffers from insufficient reproducibility, which is probably due to uncontrolled process parameters. In our work pure titanium thin films of approximately 0.6 µm in thickness were prepared on 100C6 stainless steel substrates by cathodic sputtering. The samples were subjected to secondary vacuum annealing at a temperature between 400 and 1000°C for 30 min. The reaction between substrates and thin films was characterized using an x-ray diffractometer (XRD). Surface morphology and elements diffusion evaluations were carried out by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The interaction substrates-thin films is accompanied by nucleation and growth of titanium carbide as a function of annealing temperature. By the SEM and EDS results, it appears clearly that the diffusion of manganese to the external layers leads to the destruction of adhesion especially at high temperatures.

Optimization of Welding Parameters on Wear Performance of Cladded Layer with TiC Ceramic via a Taguchi Approach

Thin composite TiC coatings in a metal matrix are ideal for components subject to heavy abrasive wear. This study examines the wear behavior of a cladded layer on a carbon steel surface, in which wear resistance was enhanced by gas tungsten arc welding (GTAW). The effects of various parameters on cladded layer wear resistance were assessed using Taguchi's parameter design. Microstructure and cladding surface hardness were assessed by optical microscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) in a cross section of samples coated under optimum processing conditions. The wear behavior of the cladded layer was studied with a block-on-ring tribometer. Excellent metallurgical bonding was formed between the composite coating and substrate. Coatings were uniform, continuous, and virtually defect free, and particles were evenly distributed in the cladded coating. Hardness was increased from HRB 6.6 to 81 in the cladded layer due to the presence of the hard TiC phase. Coatings reinforced with TiC particles revealed higher wear resistance compared to the noncladded substrate. The experimental results revealed that the key factors in wear resistance performance are welding current and welding speed. Advanced analyses by SEM indicated that the mechanisms for strengthening the cladded layer include TiC precipitation and dispersion hardening.

Effects of duty cycle on microstructure and corrosion behavior of TiC coatings prepared by DC pulsed plasma CVD

Titanium carbide coatings are deposited on hot-work steel (H11) by plasma-assisted chemical vapor deposition (PACVD) and the dependence of the corrosion behavior on fabrication parameters is investigated. Grazing incidence X-ray diffraction (GIXRD), field emission scanning electron microscopy (FESEM), Raman and electrochemical tests are used to study the structure as well as corrosion behaviors. Grazing incidence X-ray diffraction reveals the (200) plane implying that the TiC coatings are deposited via the kinetics-limited crystal growth mechanism and under thermodynamically stable conditions. The SEM results indicate that the formation of a homogeneous and uniform titanium carbide nanostructure coatings. Potentiodynamic and electrochemical impedance tests performed in 0.5M H2SO4 and 0.05M NaCl show that the TiC coating produced using a 40% duty cycle possesses high corrosion resistance in both media. The Rp values of the TiC coating (50% duty cycle) in 0.05M NaCl and the other TiC coating (40% duty cycle) in 0.5M H2SO4 are approximately four and sixteen orders of magnitude higher than that of the bare steel, respectively. Our results reveal that the duty cycles not only affect the structure and morphology of the coatings but also influence the electrochemical properties.

Influence of Zr and O on the structure and properties of TiC(N) coatings deposited by magnetron sputtering of composite TiC 0.5 + ZrO 2 and (Ti, Zr)C 0.5 + ZrO 2 targets

The effect of Zr and O incorporation on the structure and properties of TiC(N) coatings deposited by DC magnetron sputtering of composite TiC 0.5 + xZrO 2 ( x = 10 and 20 wt.%) and (Ti,Zr)C 0.5 + 10%ZrO 2 targets in an argon atmosphere or reactively in a gaseous mixture of Ar + N 2 is presented. The structure, elemental and phase composition of the coatings were studied by means of X-ray diffraction, scanning electron microscopy, and glow discharge optical emission spectroscopy. The coatings were characterized in terms of their hardness, elastic modulus, and elastic recovery using the load–depth-sensing nanoindentation method. Tribological properties were investigated using ball-on-disk tests against cemented carbide at 25 °C and alumina in the temperature range of 25–500 °C. To evaluate the oxidation resistance, the coatings were annealed in air at 400, 550, and 600 °C for 1 h. The obtained results show that the TiZrCO(N) coatings exhibit a peak hardness versus nitrogen partial pressure. The coatings with maximum hardness tested at room temperature against WC + Co and Al 2O 3 counterparts showed low friction coefficients below 0.25. At higher temperatures 300–500 °C, the friction coefficient against an Al 2O 3 ball was recorded to be 0.6. The tribological tests of the coatings demonstrated their high wear resistance at moderate temperatures 25–300 °C (wear rate, k ~ 10 − 6 mm 3N − 1 m − 1 ). Moreover, the coatings with high Zr content were the most wear resistant. The oxidation resistance of the Zr-doped TiCON coatings was not as high as expected and restricted by 600 °C. The combination of high hardness about 40 GPa with low friction coefficient and superior wear resistance makes the TiZrCON coatings promising candidates for various dry tribological applications.