CP-Ti Samples Research Articles

Combined bulk nanostructuring and surface modifications of titanium substrate for improved corrosion behavior

Titanium has proven to be a game-changing biomaterial in biomedical engineering. Titanium and its alloys offer superior properties such as machinability, mechanical strength, biocompatibility, and corrosion resistance, making them indispensable for safer and more efficient biomedical treatments. While commercially pure titanium (Cp-Ti) is an exceptional material for medical applications, it has some limitations. Allergic reactions can manifest as localized inflammation around the implant, and corrosion compromises implant stability. Corrosion starts with cracking from the surface and disrupts the protective passive oxide layer when touching body fluids, and failure occurs. This study utilized a combination of techniques including grain refinement of Cp-Ti via equal channel angular pressing (ECAP), two-step anodization (for creating titanium oxide nanotubes coatings), annealing at 450°C and 570°C, and immersion in simulated body fluid (SBF) to create a Hydroxyapatite (HA) film coating. These methods addressed various challenges and provided a positive approach to improving corrosion behavior. The microstructure of Nano-Ti was evaluated by Transmission Electron Microscopy (TEM). The morphology of the as-anodized samples and corroded areas were investigated using field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The crystalline phases of titanium nanotubes (TNTs) were evaluated through X-ray diffraction (XRD). The presence of hydroxyapatite particles was analyzed and characterized by FESEM coupled with Energy Dispersive Spectroscopy (EDS) and Fourier Transform Infrared-Attenuated Total Reflection (FTIR-ATR). The corrosion behavior was evaluated using a potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). Results indicated that grain refinement and successive surface modifications significantly impact corrosion performance. The nanostructured (Nano-Ti) sample, after the final modification stage, exhibited an approximately 11-fold decrease in corrosion rate and over a 450-fold rise in polarization resistance (7.4 MΩ) compared to as-anodized Cp-Ti sample and a 7-fold increase in its Cp-Ti counterpart, and showed excellent adhesion strength compared to other samples.

Comparative investigation of structural, morphological, mechanical, tribological and electrochemical properties of TiO2 films formed on Cp-Ti, Ti6Al4V and Ti45Nb alloys

This study focuses on the comparison of structural, morphological, mechanical, tribological and electrochemical properties of TiO2 films fabricated on Cp-Ti, Ti6Al4V and Ti45Nb alloys, which are widely used in different industries. For this purpose, TiO2 films were grown on Cp-Ti, Ti6Al4V and Ti45Nb materials by anodization method. Structural, morphological and mechanical properties of the samples were determined using XRD, SEM, Micro Raman, contact angle, surface roughness and micro hardness devices. Afterwards, the samples were subjected to wear and corrosion tests using a pin-on-disc wear device and a corrosion device, respectively. Wear tests were carried out in both dry and liquid environments. In electrochemical corrosion tests, Ringer's solution was used and open circuit potential (OCP) and electrochemical polarization analyzes were performed. According to the results of XRD and Raman analyses, it was determined that TiO2 films were successfully grown on the surface of the samples. Additionally, it was observed that these films were in Rutile and Anatase phases and their peak intensities increased with increasing anodization time. While the thickest films were obtained from Ti45Nb samples, the thinnest films were obtained from Cp-Ti samples. As a result of the increase in surface roughness with anodization, surface wettability increased in all samples. It was seen that electrical resistance of the materials was highly effective on the film thickness, surface roughness and surface structures. Wear coefficients decreased in all samples for both dry and liquid wear conditions due to the increased surface hardness and anodic film thickness and the lowest wear coefficients were obtained from the Ti45Nb sample. Corrosion performance of the samples increased with anodization because TiO2 films acted as protective layers on surface of materials.

New insights into the mechanism causing the loss of anti-corrosion property of superhydrophobic titanium surfaces

In this paper, we provide new insights into the mechanism causing the loss of anti-corrosion property of superhydrophobic titanium (SHP Ti) during potentiodynamic polarization (PDP) measurements. The water contact angle and sliding angle values of the SHP Ti, produced by a facile two-step process: anodizing and coating, were >160° and 6±2°, respectively. The anodization of Ti resulted in randomly distributed micro-clusters of TiO2-xCly covering the Ti surface homogeneously while the low surface energy organic coatings were inhomogeneous in coverage and specifically distributed over the micro-clusters alone of the anodized titanium surface. The electrochemical impedance (EIS) analysis of the SHP CP-Ti samples has shown more than an order of magnitude improvement in their barrier /polarization resistance (Rp) values at ∼ 100 MΩ.cm2 suggesting the effectiveness of the SHP coatings as a barrier against corrosion in neutral chloride environments. However, the Rp values (∼ 10 M Ω.cm2) of the SHP coatings obtained from the PDP analysis were an order of magnitude lower than the Rp values derived from the EIS. SHP CP-Ti samples showed dual passive range behaviour with an initial narrow passive region due to the porous anodized TiO2-xCly layer while the later stage passivity due to the barrier TiO2 layer, where the outer anodized porous TiO2-xCly layer was less effective against corrosion in neutral chloride media. Detailed analysis showed that in PDP, the sample lost its SHP because of the permeation of electrolyte into the hierarchical surface, due to its sensitivity to polarization, owing to the lower thickness of the organic layers. The mechanism involved in the loss of SHP and the limitation of the PDP technique for the corrosion analysis of SHP / organic coatings on metal surfaces is highlighted.

Role of coating techniques and low surface energy materials on long-term performance of superhydrophobic titanium

This study, for the first time, compares the performance of robust superhydrophobic (SHP) titanium (CP-Ti) surfaces developed by two different coating methods, (i) dip / immersion coating and (ii) spin coating, using two different low surface energy materials, (i) stearic acid and (ii) polydimethylsiloxane (PDMS). A facile two-step method for the fabrication of SHP Ti surface is followed, wherein the CP-Ti was first anodized and followed by the coating. The anodization of CP-Ti increased its surface roughness by developing a homogeneous coverage of randomly distributed micro-clusters, whose chemical composition was TiO2-xCly. Subsequent low surface energy organic coatings did not alter the surface morphology. The XPS analysis of stearic acid coated SHP Ti showed that the molecular structure of stearic acid is retained intact whereas the PDMS coated sample showed a partial modification of PDMS molecular structure with the presence of additional -[Si(O)2-O]- bonds apart from the inherent -[Si(CH3)2-O]- bonds. The water contact angle (WCA) and sliding angle (SA) values of SHP Ti were 170±5° and 6±2°, respectively. The SHP Ti showed excellent self-cleaning properties for both hydrophobic and hydrophilic contaminants. The adhesion test of the coatings showed the detachment of coating was within 5%. The coatings prepared by dip / immersion method retained their superhydrophobicity for an abrasion distance of about twice the length, (75±25 cm), due to a higher coating thickness, as compared to those obtained by the spin coating technique (40±20 cm). Further, the stearic acid-coated CP-Ti showed a better abrasion resistance while the stability of the PDMS-coated samples in different pH and Cl- environments was better. Nevertheless, both the stearic acid and PDMS-coated SHP CP-Ti samples showed excellent long-term stability against ambient atmosphere and UV exposure.

Muti-mechanism of the improving wear performance for titanium alloy via laser powder bed fusion

Wear is the key issue hindering the further application of titanium alloy. The aim of this work was to explore the strengthening mechanisms for the wear properties of Ti–15Mo alloys via laser powder bed fusion (LPBF) by the La2O3 addition. The results showed that the grain of LPBF-fabricated Ti–15Mo/La2O3 composites was obviously refined after La2O3 addition by heterogeneous nucleation and inhibited grain growth. The average grain size of Ti–15Mo/(0.2 wt%, 0.4 wt%, 0.6 wt% and 0.8 wt%) La2O3 composites is 11.75 μm, 10.85 μm, 10.39 μm, and 9.99 μm, respectively. The wear rate of Ti–15Mo/(0.2 wt% - 0.8 wt%) La2O3 composites is 1.5916 × 10−4mm3N−1m−1, 1.2885 × 10−4mm3N−1m−1, 0.6821 × 10−4mm3N−1m−1 and 0.6063 × 10−4mm3N−1m−1, respectively. Thanks to the combined effect of fine grain strengthening, grain boundary strengthening, precipitation strengthening, dispersion strengthening and dislocation strengthening, the wear resistance of the obtained sample exceeds that of the LPBF-fabricated Ti–15Mo sample more than five times and that of the LPBF-fabricated CP-Ti sample more than ten times.

Role of shielding gas and rolling treatment on mechanical properties of CP-Ti sheet fabricated by selective laser melting

Commercially pure titanium (CP–Ti) took advantages of low stiffness, high corrosion resistance and bio-compatibility, implying an ideal structural material in aerospace, military and medical industries. However, its insufficient mechanical properties have always been the long-standing obstacle for the industrial applications. In this work, we have achieved a superior strong and ductile CP-Ti via active atmosphere-assisted selective laser melting (SLM) and subsequent rolling treatment. By incorporating the active N2 atmosphere during SLM, mechanical properties of CP-Ti were substantially improved, microhardness of the lyaers with 10 at.% and 100 at.% was 63 % and 174.3 % higher than that of CP-Ti with 182.3 HV0.2, the compressive strength of 10 sample was 27.1 % higher than that of 10 L sample when the strain was 52.2 %, and ultimate tensile strength of 10 sample reached 928 MPa with an elongation of 25.6 %, and ultimate tensile strength and elongation of 10 L sample were enhanced simultaneously by 58.3 % and 13.6 % relative to CP-Ti sample. These were attributed to the interstitial strengthening induced by N atoms. After rolling treatment, the mechanical properties of N-doping layers could enhance furtherly. Macroscale cracking along the rolling direction never occur in the 10 L sample during the repeatedly rolling treatment, which could depend to high tolerability of sandwich layers for high-density dislocations. Meanwhile, rolling treatment played an important role for refining grain to enhance the strength further.

Pitting corrosion performance of plasma oxidized Cp-Ti and effects of fabrication methods

In this study, the electrochemical corrosion properties of commercial pure titanium (Cp-Ti) samples produced by additive manufacturing and forging were compared by plasma oxidizing. Plasma oxidizing processes were carried out at temperatures of 650 °C and 750 °C for 1 h and 4 h. Electrochemical corrosion experiments were carried out in Simulated Body Fluid (SBF) using open circuit potential, cyclic potentiodynamic polarization and electrochemical impedance spectroscopy methods. It was found that the coating thickness of F 750 °C-4 h and S 750 °C-4 h samples was the highest. The corrosion resistance of the samples produced by additive manufacturing is lower than that produced by forging due to the Lack of fusion (LOF) effect. The barrier layer developed by the plasma oxidizing process significantly improved the corrosion performance of additive manufacturing by reducing the LOF effect. The minimum corrosion rate was obtained at S 750°-4 h. While the total material loss due to corrosion was the lowest on this surface, the last corroded surface was F 750°-4 h. The maximum resistance was observed on the plasma oxidized surfaces for the group produced by forging.

Analyzing the corrosion and tribocorrosion performances of monolayer TiO2 and bilayer TiO2-SiO2 coatings at different SBF temperatures

In this study, monolayer TiO2 coating was formed by the anodization method and bilayer TiO2-SiO2 coating was formed by the spin-coating method on commercially pure titanium (Cp-Ti) samples. The aim of this work compare the effects of monolayer and bilayer coatings at 37 °C and 60 °C in simulated body fluid (SBF) on the corrosion and tribocorrosion behaviors of Cp-Ti material. XRD and SEM were used for structural characterization of the coatings. Afterward, the adhesion strength of monolayer and bilayer coatings was investigated. The bilayer film began to separate from the Cp-Ti surface at higher forces, which was associated with energy dissipation between the layers, increased load-carrying capacity, and increased surface hardness. The best resistance was achieved from the bilayer film in tribocorrosion experiment at both 37 °C and 60 °C SBF temperatures; the result was attributed to higher surface hardness and film thickness. Consequently, untreated, monolayer, and bilayer Cp-Ti samples were tested for adhesion strength, corrosion, and tribocorrosion and bilayer samples exhibited the highest performance.

Wear mechanism transforming of ultrafine-grained pure titanium by multi-axial forging and low-temperature annealing

The effect of microstructure and mechanical properties of submicro grained commercial pure titanium (CP–Ti) on the wear mechanism is still unclear. In the present work, CP-Ti samples were subjected to multi-axial forging (MAF) and low-temperature annealing treatment to prepare ultrafine-grained (UFG) material. The mechanical properties, microstructure, and tribological characterization between coarse-grained (CG) sample and UFG samples were comparatively studied. The results showed that the MAF sample could reach a grain size of 165 nm, while its grains coarsened slightly after low-temperature annealing. The MAF sample had the highest strength and hardness and the lowest coefficient of friction, but only a 7.3 % decrease in wear rate compared to the CG sample. The 400 °C annealed MAF sample possessed a good combination of tensile strength (814 MPa) and elongation (18.6 %), resulting in the lowest wear rate of 16.8 × 10−5mm3/(N∙m). The dominated wear mechanisms of the CG sample, MAF sample and 500 °C annealed MAF sample were abrasive wear, adhesive wear and delamination wear, while the primary mechanism of the 400 °C annealed MAF sample was abrasive wear and adhesive wear. It was found that the wear mechanism transforming, higher hardness and sufficient work hardening could be responsible for lower wear rate of the 400 °C annealed MAF sample. The 400 °C annealed MAF sample showed a thinner and more homogeneous deformation layer near the worn surface, and its thickness of deformation layer was about 8 μm.

Exploring the potential of a newly developed pectin-chitosan polyelectrolyte composite on the surface of commercially pure titanium for dental implants

Pectin and chitosan are natural polysaccharides obtained from fruit peels and exoskeletons of crustaceans and insects. They are safe for usage in food products and are renewable and biocompatible. They have further applications as wound dressings, body fat reduction, tissue engineering, and auxiliary agents in drug delivery systems. The healing process is usually long and painful. Adding a new material such as a pectin-chitosan composite to the implant surface or body would create unique biological responses to accelerate healing and delivery of target-specific medication at the implant site. The present study utilized the electrospraying process to create pectin-chitosan polyelectrolyte composite (PCPC) coatings with various ratios of 1:1, 2:1, 1:2, 1:3, and 3:1 on commercially pure titanium substrates. By means of FESEM, AFM, wettability, cross-cut adhesion, and microhardness were assessed the PCPC coatings’ physical and mechanical properties. Subsequently, the antibacterial properties of the coating composite were assessed. AFM analysis revealed higher surface roughness for group 5 and homogenous coating for group 1. Group 3 showed the lowest water contact angle of 66.7° and all PCPC coatings had significantly higher Vickers hardness values compared to the control uncoated CpTi samples. Groups 3 and 4 showed the best adhesion of the PCPC to the titanium substrates. Groups 3, 4, and 5 showed antibacterial properties with a high zone of inhibitions compared to the control. The PCPC coating's characteristics can be significantly impacted by using certain pectin-chitosan ratios. Groups 3 (1:2) and 4 (1:3) showed remarkable morphological and mechanical properties with better surface roughness, greater surface strength, improved hydrophilicity, improved adhesion to the substrate surface, and additionally demonstrated significant antibacterial properties. According to the accomplished in vitro study outcomes, these particular PCPC ratios can be considered as an efficient coating for titanium dental implants.

Investigation of surface wettability, corrosion and tribocorrosion behavior of machined, etched, blasted and anodized Cp-Ti samples

Investigation of surface wettability, corrosion and tribocorrosion behavior of machined, etched, blasted and anodized Cp-Ti samples

Correlation of microstructure and bio-tribocorrosion behavior of equal channel angular pressed pure titanium

The effect of equal channel angular pressing (ECAP) strain (i.e., 1st to 4th pass) on the grain size and eventual mechanical and bio-tribocorrosion properties of commercially pure titanium (cp-Ti) has been investigated. Ultra-fine grains (UFG) of 0.8 µm size (from 12 µm) and yield strength enhancement to 785 MPa (from 381 MPa) have been observed for the ECAP 4th pass sample as compared to the annealed condition of cp-Ti. In addition, the maximum hardness increased by 101 HV to 293 HV in the 4th pass samples due to grain refinement caused by the ECAP process. Further, the tribocorrosion behaviour as a function of cp-Ti sample conditions in the simulated body fluid (SBF) has been evaluated. The ultra-fine-grained 4th pass sample shows a lower coefficient of friction (CoF) of ∼0.35 (from ∼0.5) and wear loss due to its enhanced strength than the annealed sample. Moreover, the ECAP 4th pass sample, because of its UFG, exhibits a more negative potential shift (∼0.82 V) as compared to annealed sample (∼0.88 V). However, this shift is marginal due to its low wear scar width and depth, which eventually induced less galvanic coupling effect in it. Abrasion and adhesion are the primary wear mechanisms for all the sample conditions.

The study of hydroxyapatite growth kinetics on CP – Ti and Ti65Zr treated by Plasma electrolytic oxidation process

The kinetics of hydroxyapatite growth on titanium alloys (CP–Ti and Ti65Zr) was studied. Specimens were treated by Plasma Electrolytic Oxidation (PEO) and immersed into the Hanks' solution. The PEO method was performed at AC mode with the current density of 4 A/dm2 in an electrolyte containing calcium acetate and calcium glycerophosphate, allowing the inclusion of calcium and phosphorus in the obtained oxide layer, which promotes the osseointegration when applied to bone tissue. The treated specimens were immersed in the Hanks’ solution with different exposure times, followed by studying changes in morphology, chemical, and phase composition. In addition, the surface wettability was tested, and the corrosion behavior of the treated samples was investigated. Tiny HA crystals can be seen on the surface of CP-Ti samples treated by PEO for 5 and 30 min. The morphology with a distinct layer of HA was obtained for the Ti65Zr sample after 5 min of PEO treatment. As for the immersion times, the highest crystal growth velocity was observed for the Ti65Zr of 5 min of PEO and 14 days of immersion. The change in morphology and EIS analysis confirms the observed behavior. Finally, based on the XRD analysis for the Ti65Zr of 5 min PEO treatment samples, the Srilankite phase in an amount of 60% is responsible for the crystal growth, resulting in the best crystal growth velocity and good corrosion properties (Rp = 0.732 MΩ cm2).

Surface and Tribological Properties of Powder Metallurgical Cp-Ti Titanium Alloy Modified by Shot Peening

The present study reveals for the first time the dry sliding wear behavior of a powder metallurgical pure titanium alloy (Cp-Ti) modified by shot peening. Cp-Ti samples were manufactured via powder metallurgy, and then their surface and subsurface features were modified using a custom-made, fully automated shot-peening system. The texture isotropy rate and the highest orientation angle of the shot-peened samples were 71.5% and 36°, respectively. The Abbott curves of the shot-peened surfaces revealed that the most common areal roughness value was 5.177 μm, with a frequency of 8.1%. Shot-peened surfaces exhibited an ~20% lower wear rate than unpeened surfaces under dry sliding wear, whereas the coefficient of friction was the same for both surfaces. Micro-ploughing, micro-cutting, oxidation, and three-body abrasion wear mechanisms were observed on the shot-peened and unpeened surfaces. High resolution 3D surface topographies of worn unpeened and shot-peened surfaces revealed micro-scratches and inhomogeneities along wear tracks, which are indicative of three-body abrasion mechanisms during contact. In addition, vertical and horizontal microcracks were visible just beneath the wear track, suggesting a clear indication of plastic deformation during contact. The cross-sectional hardness maps of shot-peened samples revealed the formation of a work-hardened surface layer with shot peening, which improved the wear resistance. These findings support that shot peening can be a useful tool to modify the surface and tribological properties of powder metallurgical Cp-Ti alloys.

Comparison of the structural properties, surface wettability and corrosion resistance of TiO2 nanotubes fabricated on Cp-Ti, Ti6Al4V and Ti45Nb

In this study, the synthesis of TiO2 nanotubes (TNT), which are widely used in many fields such as biomedical, solar cell, drug delivery, etc., was performed on Cp-Ti, Ti6Al4V, and Ti45Nb alloys with different parameters. The aim of this research is to investigate the structural properties, surface wettability and corrosion resistance of nanotubes fabricated in three different titanium alloys. XRD, Micro-Raman, XPS, SEM and a surface tension meter were used to characterize the nanotubes. The diameters of the synthesized nanotubes were found to have a significant effect on the surface wettability. The creation of anatase and rutile phase structures and the length of TiO2 layers/nanotubes improved the corrosion resistance by preventing the SBF to reach the substrate. The longest nanotubes were found in the Ti45Nb alloy samples, the nanotubes with the largest diameter in the Ti6Al4V samples and the nanotubes with the thickest walls in Cp-Ti samples.

Investigation of corrosion and tribocorrosion behavior of boron doped and graphene oxide doped TiO2 nanotubes produced on Cp-Ti

In this study, undoped, boron doped and graphene oxide doped TiO2 nanotubes (TNT) were synthesized on Cp-Ti (commercially pure titanium) samples. The aim of this research is to investigate the structural properties, surface wettability, corrosion resistance and tribocorrosion behavior of boron and graphene oxide doped TNT. XRD, Micro-Raman, XPS, SEM and a surface tension meter were used to characterize the nanotubes. It was found that the increasing surface roughness and contact area of the synthesized nanotubes improved the surface wettability. By preventing the SBF liquid from reaching the substrate material, the anodic films formed in all TNT-synthesized samples improved the corrosion resistance. The ceramic TiO2 structure formed on the surface increased the surface hardness and consequently, wear resistance improved. The best tribocorrosion resistance was obtained from the graphene oxide doped TNT, which has the longest tubular architecture.

Synthesis and characterization of wear and corrosion resistant Ni-doped Al2O3 nanocomposite ceramic coatings by sol-gel method

Cp-Ti is frequently used in biomedical applications because of its good corrosion and high biocompatible properties. However, its poor wear resistance limits its use in some applications. Therefore, this study aims to improve its wear and corrosion resistance by producing Ni-doped Al2O3 nanocomposite coatings on Cp-Ti. In order to achieve this goal, undoped Al2O3 and Ni-doped Al2O3 nanocomposite ceramic coatings were produced on Cp-Ti samples at two different rotational speeds by the spin coating process, which is a sol-gel method. Afterward, their structural and morphological features were examined by XRD, SEM, Raman, and 3D surface profilometer. Reciprocating wear tests and electrochemical investigations were performed to determine their wear and corrosion properties.

Surface characteristics of plasma electrolytic oxidation coatings on Cp-Ti and hot-dip aluminised Cp-Ti

ABSTRACT Plasma electrolytic oxidation (PEO) coatings on commercial pure titanium (Cp-Ti) and hot-dip aluminised Cp-Ti surfaces were prepared in an alkaline electrolyte. The morphological, structural, wear, and corrosion characteristics of the coatings were studied by using SEM, EDS, XRD, electrochemical polarisation, and dry sliding wear tests. The experimental results showed that the main compositions of the PEO coating on Cp-Ti are TiO2 and Al2TiO5 phases, while the PEO coating on hot-dip aluminised (HDA’ed) Cp-Ti mainly consists of the Al2O3 phase. The single PEO coating exhibited more porosity with small diameter micro-pores compared to the PEO coating on the HDA’ed sample. Electrochemical polarisation tests revealed that the PEO coating on the HDA'ed sample exhibited approximately 4.6 times more polarisation resistance than the single PEO coating and 10 times that of the bare Cp-Ti sample. According to the wear test results, the wear resistance of the bare Cp-Ti was doubled by hot-dip aluminising (HDA) and PEO treatments, while the single PEO treatment resulted in better resistance against dry sliding wear.

Additive manufacturing of Ti-Ni bimetallic structures

Bimetallic structures of nickel (Ni) and commercially pure titanium (CP Ti) were manufactured in three different configurations via directed energy deposition (DED)-based metal additive manufacturing (AM). To understand whether the bulk properties of these three composites are dominated by phase formation at the interface, their directional dependence on mechanical properties was tested. X-ray diffraction (XRD) pattern confirmed the intermetallic NiTi phase formation at the interface. Microstructural gradient observed at the heat-affected zone (HAZ) areas. The longitudinal samples showed about 12% elongation, while the same was 36% for the transverse samples. During compressive deformation, strain hardening from dislocation accumulation was observed in the CP Ti and transverse samples, but longitudinal samples demonstrated failures similar to a brittle fracture at the interface. Transverse samples also showed shear band formation indicative of ductile failures. Our results demonstrate that AM can design innovative bimetallic structures with unique directional mechanical properties.

Influences of Ti, Al and V metal doping on the structural, mechanical and tribological properties of DLC films

DLC films are widely used in different engineering products. However, some problems such as inadequate toughness, insufficient adhesion and internal stresses affect their performance. Therefore, we aimed to enhance the mechanical and tribological features of Cp-Ti by metal-free and metal-doped DLC films in this study. Cp-Ti samples were coated with un-doped and Ti, Al and V metal-doped DLC films by PVD. Their properties were investigated by Raman, XPS, XRD, SEM and wear tester. The results revealed that the incorporation of metal in DLC increased the disorder. Ti, Al and V carbides formed on DLC due to bonding of doping elements with carbon. Metal-doping improved the adhesion and decreased the internal stresses and these improvements caused metal-doped films to exhibit better tribological properties than metal-free film.