Titanium Dioxide Thin Films Research Articles

Microstructural, optical, and photocatalytic properties of TiO2–Bi2O3–GO thin films obtained by sol-gel for applications with sunlight

The following study presents the structural, optical, and photocatalytic properties of thin films of titanium dioxide (TiO2) and bismuth trioxide (Bi2O3) in their pure state, as well as mixtures of both oxides in different atomic proportions (with respect to Ti and Bi) and as films modified with a dispersed phase of graphene oxide (GO). The films were sintered at 400 °C, 450 °C, 500 °C and 550 °C. The synthesis of the oxides was carried out by the sol-gel method and the material deposits were synthesized by the dip-coating technique. For mixtures with atomic proportions of 50% and 70% Bi2O3, bismuth titanates were obtained with Bi2(Ti2O7) (cubic) stoichiometry at 550 °C and Bi4Ti3O7 (orthorhombic) stoichiometry at 500 °C, respectively. It was determined that the Bi2(Ti2O7) compound presents the best photocatalytic properties in the degradation of tartrazine in aqueous solution using solar radiation, achieving up to 30% in the photodegradation of the dye. The GO was incorporated in 2% p/p to the precursor solutions of TiO2 and Bi2O3; the resulting materials presented a better photocatalytic activity.

Local structural and sensing properties of TiO2 thin film using the PVD method

This paper studied the structural, morphological, optical, and X-ray absorption near-edge spectroscopy (XANES) and sensing properties of titanium dioxide (TiO2) thin film. The TiO2 thin film is prepared in the thin film laboratory on a clean glass plate using a physical vapor deposition (PVD) method. The structural, morphological, Optical, and electronic properties of the fabricated samples are presented by X-ray diffraction (XRD), atomic force microscope (AFM), UV-visible, and XANES. It is found from XRD the crystallite size was ∼25.66 nm with microstrain ∼0.0064 using the Williamson-Hall (W-H) plot. The fractal terms such as grain size, roughness, kurtosis, and skewness were estimated using AFM. The grain size lies in the nanometric range and found that ∼77.21 nm. The band gap of the fabricated film is ∼3.23 eV. The XANES analysis is well supported by XRD measurement and the result found that the fabricated TiO2 thin film was anatase phase. The sensing properties of TiO2 are studied for the detection of Liquified Petroleum Gas (LPG) concentration (0-5000 ppm) at room temperature. Results found that the TiO2 film is highly sensitive and is the fast response for LPG gas sensors with a maximum sensitivity of ∼198 %.

Flexible Antibacterial Respiratory Monitoring Sensor Based on Controllable Au-Modified Surface of Highly {001} Preferred Anatase Titanium Dioxide Thin Film.

Respiratory signals are critical clinical diagnostic criteria for respiratory diseases and health conditions, and respiratory sensors play a crucial role in achieving the desired respiratory monitoring effect. High sensitivity to a single factor can improve the reliability of respiratory monitoring, and maintaining the hygiene of the sensors is also important for daily health monitoring. Herein, we propose a flexible Au-modified anatase titanium dioxide resistive respiratory sensor, which can be mechanically compliantly attached to curved surfaces for respiratory monitoring in different modalities (i.e., respiratory intensity, frequency, and rate). The uniform and preferentially oriented anatase titanium dioxide films gained by the polymer-assisted deposition technique can be fabricated on flexible substrates through a liquid-assisted transferring process. The Au modification can enhance surface plasmon resonance to facilitate the photocatalytic activity of titanium dioxide, and the optimized distribution of Au on the surface of titanium dioxide film made the sensor have an excellent antibacterial effect. The uniquely designed encapsulation can effectively control the contact between the surface of titanium dioxide films and electrodes, allowing the flexible sensor to exhibit fast response time (0.71 s) and recovery time (1.06 s) to respiratory as well as insensitivity or low sensitivity to other factors (i.e., gas composition, humidity, temperature, stress, and strain). This work provided an effective strategy for flexible wearable respiratory sensors and has great potential in daily respiratory monitoring for health management and pandemic control.

Nanostructured TiO2 thin films sputtered at room temperature as electron transport layer for flexible perovskite solar cell applications: Impact of varying RF power

This work examines the adoption of radio frequency (RF) sputtering at power ranging from 100 to 300 W to deposit nanostructured titanium dioxide (TiO2) thin films on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) flexible substrate (ITO/PET) at room temperature. At higher RF power, X-ray diffraction (XRD) results exhibited evolution from amorphous into crystalline anatase with preferred (101) orientation and the films revealed spherical-like nanostructures with increasing grain size from 15.71 to 21.57 nm. Films transparency decreased from 79% to 70%. Estimated energy gap decreased from 3.57 to 3.36 eV, while refractive index increased from 2.19 to 2.25, denoting a red shift in the films. The thin film deposited at 300 W exhibited high conductivity and mobility of 19.65 × 10−5 Ω−1 cm−1 and 0.30 cm2/Vs, respectively. The film demonstrated its capability as an electron transport layer for flexible perovskite solar cells.

Superior Performances of Q-Switched and Mode-Locked Erbium-doped Fiber Laser using Black Titanium Dioxide Thin-film Saturable Absorbers

This work reports on the improved Q-switched and mode-locked performances of black titanium dioxide (BTiO2-x) nanoparticles embedded in thin-film composite material as a saturable absorber compared to TiO2 in an erbium-doped fiber laser. The thin-film saturable absorbers were prepared by mixing the nanoparticles with polyvinyl alcohol (PVA) as a host. BTiO2-x has a better nonlinear absorption coefficient, β of -12.46 x 10-7 m/W compared to -7.15x 10-7 m/W for TIO2 determined using z-scan measurement. The laser performance was evaluated in the 85.21 mW – 126.48 mW pump power range. Upon inserting TiO2 and BTiO2-x SA in a laser cavity, the peaks of the output spectrum shifted from 1566.62 nm to 1563.24 nm and 1565.75 nm, respectively. Regarding Q-switched performances, BTiO2-x SA generates a shorter pulse width of 16.00 µs than TiO2 SA. The slope efficiency of the TiO2 SA was 11.72 %, which is higher than the slope efficiency of the BTiO2-x SA. The maximum average and peak power generated by the BTiO2-x SA were 55.67 % and 54.83 % higher than the TiO2 SA. As for mode-locked outputs, BTiO2-x SA can generate pulsed laser at a low threshold power of 62.29 mW compared to TiO2 SA. Furthermore, BTiO2-x SA produced a shorter pulse width of 5.04 ps, whereas TiO2 is 9.20 ps. This study demonstrates that BTiO2-x SA has the potential to produce ultrashort pulse width using the mode-locked technique.

Highly Sensitive Wearable Sensor Based on (001)-Orientated TiO2 for Real-Time Electrochemical Detection of Dopamine, Tyrosine, and Paracetamol.

The concentration of dopamine (DA) and tyrosine (Tyr) reflects the condition of patients with Parkinson's disease, whereas moderate paracetamol (PA) can help relieve their pain. Therefore, real-time measurements of these bioanalytes have important clinical implications for patients with Parkinson's disease. However, previous sensors suffer from either limited sensitivity or complex fabrication and integration processes. This work introduces a simple and cost-effective method to prepare high-quality, flexible titanium dioxide (TiO2) thin films with highly reactive (001)-facets. The as-fabricated TiO2 film supported by a carbon cloth electrode (i.e., TiO2-CC) allows excellent electrochemical specificity and sensitivity to DA (1.390µAµM-1cm-2), Tyr (0.126µAµM-1cm-2), and PA (0.0841µAµM-1cm-2). More importantly, accurate DA concentration in varied pH conditions can be obtained by decoupling them within a single differential pulse voltammetry measurement without additional sensing units. The TiO2-CC electrochemical sensor can be integrated into a smart diaper to detect the trace amount of DA or an integrated skin-interfaced patch with microfluidic sampling and wireless transmission units for real-time detection of the sweat Try and PA concentration. The wearable sensor based on TiO2-CC prepared by facile manufacturing methods holds great potential in the daily health monitoring and care of patients with neurological disorders.

Characterization of titanium oxide thin films obtained by galvanostatic anodization in black acacia pyroligny liqueur

The condensation of smoke from the pyrolysis of black wattle for the production of charcoal generates a by-product known as pyroligneous liquor. It is widely used in the agricultural area as a fertilizer and phytosanitiser, and its chemical composition presents compounds rich in hydrogen and oxygen, which makes it a potential electrolyte for anodizing. Thus, black wattle pyroligneous liquor was used as anodizing electrolyte for commercially pure titanium. The anodized surfaces were characterized in terms of topography by scanning electron microscopy (SEM); regarding the crystalline structure by X-ray diffraction (DRX); to electrochemical behavior by open-circuit potential (OCP) and electrochemical impedance spectroscopy (EIS); regarding wettability by the sessile drop method; and for semiconductor behavior by UV–visible spectrophotometry. The results showed that the anodized TiO2 film obtained forms interfering colors, with an estimated thickness between 18.4 and 52 nm, being basically amorphous with crystalline concretions that appear with the anodization time. In addition, they exhibit hydrophilic behavior in water and maintain the electrochemical passivity of native titanium oxide, as well as showing semiconductor characteristics with a band gap between 1.75 and 2.9 eV.

Characterization and photocatalytic activity of TiO2 thin films prepared by sol-gel method for NOx degradation

Titanium dioxide (TiO2) thin film photocatalysts for the elimination of nitrogen oxides (NOx) were prepared by the dip-coating process using the sol–gel method. To prepare the sols, titanium (IV) butoxide (Ti(OBu)4), diethanolamine (DEA), butanol, and HCl were chosen. The TiO2 coatings were prepared using sols with varying volume ratios of Ti(OBu)4:DEA:Butanol. Additionally, three withdrawal speeds from the sol were employed. Subsequently, the TiO2 thin films were sintered at 500 and 700 °C. The obtained thin films were characterized using SEM to determine thickness, AFM to determine roughness, and the Step 500 platform for the adhesion test. NOx was found to be efficiently eliminated by TiO2 thin film photocatalyst. It is possible to obtain a TiO2 coating that is capable of degrading 300 ppb of NO in real time under specific conditions: a relative humidity of 30 %, a UV intensity of 20 W/m2, a gas flow rate of 1 dm3/min.

Investigations of TiC and SiC films synthesized by DC magnetron sputtering and thermal annealing

In this research article, two-dimensional thin films of titanium, hierarchical titanium-carbon, titanium carbide, hierarchical silicon-carbon, and silicon carbide films were synthesized on the plates of AISI 304 stainless steel and glass slides, individually, using DC magnetron sputtering techniques. During the sputtering process, the creation of stable plasma was affected by the vacuum level, DC potential, plasma current, and Argon gas. The results showed that the coatings of titanium, titanium-carbon, and titanium carbide modified the optical properties of stainless steel. Additionally, titanium carbide coatings displayed a shiny gold appearance with a hardness of 1500 HV. Besides this, X-ray diffraction studies revealed a hexagonal Ti in the metallic films and C60, and diamond-like structures dispersed on its surface after the carbon coating. The spherical particulates of Ti and C60/diamond-like carbon particulates anchored on its surface were observed using scanning electron microscope analysis. The structural analysis indicated C vacant sites, which are available for ionic/electronic charge diffusion, thereby rendering these structures suitable for making Li storage batteries as electrode material.

Integration of a recyclable silver substrate for in situ surface-enhanced Raman spectroscopy in digital microfluidics.

We report a new chip-integrated recyclable SERS substrate, achieved by photochemical deposition of silver nanoparticles onto titanium dioxide (TiO2) thin film. Facilitated by the photocatalytic activity of titanium dioxide the SERS substrate can be recycled for multiple analysis. This enables quasi-real time detection of various compounds in an automated and reusable DMF-SERS platform.

Sol-gel Spin Coated Hydrophilic Composite Titania-Silica Coatings on the Glass Substrates for Automotive Applications

The pollutants from the environment can also degrade the surface of the glass, which result in loss of transmittance of the glass surface. This necessitates the formation of a dedicated crew for the correct maintenance of glass furniture, notably in the Middle East. In this paper, we describe sol-gel spin coating of titania thin films on glass substrates, which may function as a hydrophilic coating by spreading water molecules across the substrate and removing pollutants and other dust particles, hence eliminating the need for maintenance and wipers. The fabricated coating was tested with X-ray diffractogram (XRD) and evidenced anatase nature of titania and amorphous nature of silica at Bragg angle 25° in the coating. Fourier transform infrared spectroscopy (FTIR) investigations endorsed Ti-O-Ti and Si-O-Si functional linkages at wavenumbers 551, and 957 cm-1 demonstrating the presence of titania and silica in the as-developed coating. Cross sectional field emission scanning electron microscopy (FESEM) investigation evidenced the formation of composite titania-silica film on the glass substrate with a thickness about 36 nm. The coating transmittance was studied by ultraviolet-visible and near-infrared (UV-Vis-NIR) spectroscopy and found 95% transmittance in the visible region. Moreover, wetting study utilizing the sessile drop technique yielded a 74° contact angle when the water droplets were interacted.

The Effect of Copper Doping on Some Structural and Electrical Properties of Titanium Dioxide Nanofilms

Thin films of titanium dioxide (TiO2) with several copper ratios were deposited on glass substrates using pulsed laser deposition (PLD) for pure and doped samples (TiO2 Pure, 1 % Cu, 2 % Cu, and 3 % Cu), energy (600 mJ), and frequency (6 Hz). X-ray diffraction (XRD) showed that the width of the peaks decreases with increasing the ratio of doping with copper. This leads to an increase in the crystal size and in the intensity of the copper peaks, as well as a gradual decrease in the intensity of the titanium dioxide peaks. The results of the atomic force microscope showed that increasing the inoculation percentage leads to an increase in the surface roughness and the average grain diameter, and thus an increase in the growth of the particle size. The electrical tests (Hall effect) showed that the prepared films are of (n-type) and that the concentration of carriers (n) increased with the doping ratio, while the mobility values ​​(µH) decreased directly with the increase in copper. The electrical conductivity (DC) test showed an increase in the activation energy as a result of the increase in the copper inoculation percentage and thus the electrical conductivity increases.

On the Scope of the Oxygen Plasma Treatment on FTO Electrodes for Electrochemical Processes

The cleaning and/or activation of electrodes for electrochemical purposes using the oxygen plasma treatment has been widely used because of its proven effectiveness to improve the properties of electrodes. Beyond its cleaning effect, the plasma can either create stepped and functionalized carbon-based materials which are active for specific electroanalytes and increase their capacitance [1]. Prussian Blue can also be activated by creating oxygen rich sites thus enhancing its electrochromism [2]. In the case of transparent conductive oxides (TCOs) electrodes such as FTO and ITO-coated glass this treatment has proven to be suitable in the preparation of spray-pyrolyzed titania thin films used as blocking hole layer or electron transporting layer in efficient third generation solar cells [3]. However, the role of this treatment on TCOs when used for electrochemical purposes has not been deeply explored yet. The reason to carry out this study lies in the great number of electrochemical processes that are usually employed for the growth of wide and middle band gap semiconductor metal oxides and chalcogenides with applications in photoelectrochemical and photovoltaic cells [4].To assess the role of the oxygen plasma, FTO was chosen as TCO reference material and the effect of different time exposure and power of plasma was analysed by electrochemical polarization in aqueous media for both anodic and cathodic directions. In the former, PbO2 electrodeposition and oxygen evolution reaction (OER) were considered. In the later, hydroxide generating reactions that usually precipitate in presence of transition metal cations were studied: i) the oxygen reduction reaction (ORR, Figure 1), ii) hydrogen peroxide reduction. Further, the reduction of S8 in DMSO media to sulphide ion was also considered as an aprotic media to growth chalcogenides. Interestingly, all these electrochemical reactions exhibited an increased activation overpotential. The behaviour of treated FTO for OER demonstrated the as implanted oxyanions do not act as source of molecular oxygen as previously claimed [5]. This was verified by the poorly response of ORR after anodic polarizations in acid media.Besides, contact angle measurements allowed to estimate the energetic of the FTO surfaces being these energies correlated with open circuit potential values. Capacitance (Mott-Schottky plots), XPS, UPS and UV-Vis spectroscopy were used to study the semiconductor energy levels of both treated and untreated FTO electrodes. The oxyanion implantation in the oxygen vacancies would be responsible of the sharply diminution of the ORR wave. However, the electrochemical response of the well-known Ferri/Ferro couple only suffered changes under highly aggressive treatments, i.e. for long times or power. Meanwhile, XRD data has shown only slight changes in the structural features of FTO. We can conclude that oxygen plasma treatment is not suitable in FTO for electrochemical purposes, contrary to other deposition methods. Surprisingly, an exception in metals deposition (Ni and Zn) was found.

Structural, Optical, and Electrical Characteristics of Titanium Dioxide Thin Films Prepared by Pulsed Laser Deposition

In this research, the Pulsed Laser Deposition (PLD) technique was used, and the operating frequency of the laser was tuned to a double frequency. This was done in order to construct nano-thin films of titanium oxide (TiO2). An Nd-YAG laser with a wavelength of 1064 nm, pulse frequency of 6 Hz, and laser energy of 700, 800, and 900 mJ were used on glass and Si (p-type) substrates of different thicknesses. Then, the TiO2 films were annealed for 2 hours at a temperature of 400 °C. UV-Vis spectra revealed that TiO2 has strong UV absorption, as well as a large energy gap (2.9, 3.06, and 3.3) eV for energy levels (700, 800, and 900) mJ in contrast. In addition, FESEM analysis showed a granular morphology that showed a tendency for fragmentation into smaller particles with the growth of the thickness of the sample. The thickness of the thin films was determined using the FESEM cross-section, and the results showed that the thicknesses were 278.01, 1630.53, and 2579.66 nm for TiO2 at laser energy of 700, 800, and 900 mJ, respectively. As the laser energy increased, the results showed an increase in the thickness of the thin film. In addition, the absorbance increased while the transmittance decreased with increasing thin film thickness. In terms of the electrical properties of the cell, we found that the efficiency of the annealed cell was significantly increased compared to that of the unannealed cell.

Integrated synthesis and comprehensive characterization of TiO2/AgBi2S3 ternary thin films via SILAR method

AgBi2S3, a copious and innocuous ternary metal chalcogenide affiliated with the I-V-IV group of semiconductors, was synthesized. With an energy gap of 1.2eV, it closely matches the optimal 1.39eV for solar cell absorbers. Importantly, this chalcogenide exhibits a high absorption coefficient of 105 cm−1 at 600 nm. Using the successive ionic layer adsorption and reaction (SILAR) method; we deposited an AgBi2S3 thin film onto a titanium dioxide (TiO2) thin film. Characterization techniques encompassed XRD, SEM, EDXS, UV–Vis, EIS, and PEC performance analyses. The resulting TiO2/AgBi2S3 composite film ranged in thickness from 8 μm to 13 μm, with particle sizes spanning 20 nm–265 nm. Notably, the deposition of AgBi2S3 onto the TiO2 film caused depreciation in the TiO2 energy gap from 3.1eV to 1.7eV. Furthermore, it significantly enhanced the TiO2 film's absorbance across the visible and near-infrared regions. Intriguingly, the TiO2/AgBi2S3 composite film also exhibited discernible photoelectrochemical behavior.

Effect of chromium doping on the band gap tuning of titanium dioxide thin films for solar cell applications

A simple and inexpensive spray pyrolysis deposition (SPD) approach was used to produce TiO2 and Cr (2–8) at.%-doped TiO2 thin films. To explore the morphological features of the films, FE-SEM micrographs were used and found that 6 and 8 at.% TiO2:Cr films had fibrous patterns with diameters of 0.45 and 0.78 μm, respectively, while the remainder of the films were agglomerated particles. From X-ray diffraction investigation, it was found that the TiO2 thin films had an anatase crystal phase (tetragonal) up to 6 at.% Cr doping, while an anatase-rutile mixed crystalline phase was identified for 8 at.% Cr doping. The crystallite size of the pristine TiO2 film was 35 nm, while for TiO2:Cr films, it ranges from 35 to 46 nm. The Fizeau fringes technique was employed to measure the thickness of the TiO2 film and 165 nm was found for pristine TiO2 and 164–180 nm for TiO2:Cr films. UV–visible spectroscopy was used to study optical properties such as absorbance, refractive index, optical band gap, dielectric constant, and optical conductivity. As the Cr concentration increases, the optical band gap decreases from 3.40 eV to 2.70 eV. Using the four-point probe method, it was found that the resistivity changes with temperature and is also affected by the Cr content.

Electroactive Prussian Blue Analogues/TiO2 Nanocomposites Obtained through SILAR Assembly in Mesoporous Nanoarchitectures

AbstractThe preparation of nanomaterials for energy applications such as intercalation batteries and materials that can act as substrates for water oxidation is a subject of major interest nowadays. In this work, we report the deposition of Prussian blue (PB) and its cobalt analogue (CoPBA) on mesoporous titania thin films (MTTF) using the successive ionic layer adsorption reaction (SILAR) technique under soft conditions. A bifunctional ligand, 1,10‐phenanthroline‐5,6‐dione (pd), was used to functionalize the titania surface and promote the growth of PB and CoPBA. The resulting PB@MTTF and CoPBA@MTTF nanocomposites were characterized using several techniques and it was determined that PB and CoPBA grow in a controlled and sequential manner, maintaining the mesoporous architecture. Both PB@MTTF and CoPBA@MTTF demonstrated very good electroactive properties, while CoPBA@MTTF exhibited water oxidation capabilities. The flexibility of this PBA@MTTF platform allows the incorporation of any labile transition metal ion or fragment into the structure of the coordination polymer embedded into a mesoporous matrix, opening the door for (photo)electrochemical devices and catalysts.

Reactive remote plasma sputtering of TiOx thin films and controlled growth of textured single-phase rutile using rf substrate biasing

Titanium oxide (TiOx) thin films were deposited by remote plasma sputtering (RPS) with the use of rf substrate bias onto unheated and water-cooled glass, Si, and Kapton substrates. The rf remote plasma power was kept constant (2.0 kW) and the properties of the films were studied as a function of deposition rate and substrate bias voltage. Four different reactive processes at four different deposition rates were developed under zero bias conditions by altering the target bias voltage and the flow of oxygen to give highly transparent TiOx films. These processes were studied with varying substrate bias voltage and the film structural, optical, and surface properties were investigated by GI-XRD, SEM, transmission, and sessile drop measurements. The changes in film structure and properties observed were related to the plasma conditions of the RPS system, investigated by dc electrical probe and OES measurements, and compared with other observations for films deposited under energetic conditions in the literature. All films deposited under zero bias conditions exhibited amorphous structures in GI-XRD and SEM images. Sufficient application of substrate bias was seen to promote columnar growth in cross-sectional SEM images and to crystallise phase pure rutile with no detection of the anatase phase in GI-XRD. Rutile bearing films were noted for their change in optical properties. Further increase of the substrate bias voltage caused a change in the texture of the rutile films from a low-energy [110] preferred orientation to a high-energy [101] and [002] preferred orientation. Contact angles of water with deposited films were found to increase with increasing substrate bias voltage and decreasing deposition rate. Film stress was also found to be influenced mainly by the substrate bias voltage process parameter.

Endoscope Capsules: The Present Situation and Future Outlooks.

This paper presents new perspectives on photonic technologies for capsule endoscopy. It first presents a review of conventional endoscopy (upper endoscopy and colonoscopy), followed by capsule endoscopy (CE), as well as their techniques, advantages, and drawbacks. The technologies for CEs presented in this paper include integration with the existing endoscopic systems that are commercially available. Such technologies include narrow-band imaging (NBI), photodynamic therapy (PDT), confocal laser endomicroscopy (CLE), optical coherence tomography (OCT), and spectroscopy in order to improve the performance of the gastrointestinal (GI) tract examination. In the context of NBI, two optical filters were designed and fabricated for integration into endoscopic capsules, allowing for the visualization of light centered at the 415 nm and 540 nm wavelengths. These optical filters are based on the principle of Fabry-Perot and were made of thin films of titanium dioxide (TiO2) and silicon dioxide (SiO2). Moreover, strategies and solutions for the adaptation of ECs for PDT are also discussed.

The Deposition and Properties of Titanium Films Prepared by High Power Pulsed Magnetron Sputtering

Titanium thin films are particularly important as electrode layers, barrier layers, or intermediate buffer layers in the semiconductor industry. In order to improve the quality of Ti thin films and the adhesion and diffraction abilities of irregular parts, this paper used high-power pulsed magnetron sputtering (HPPMS/HiPIMS) to prepare titanium thin films. The effects of different trigger voltages (700 V, 800 V, and 900 V) on plasma properties were studied, and the microstructure, mechanical properties and corrosion resistance of the films were also studied. The results showed that as the voltage increased, the grain size of the thin films gradually increased. The residual stress of the titanium films changed from compressive stress (−333 MPa) to tensile stress (55 MPa) and then to low compressive stress (−178 MPa). The hardness values were 13 GPa, 9.45 GPa and 6.62 GPa, respectively. The wear resistance of the films gradually decreased, while the toughness gradually increased. The corrosion resistance of the films decreased as well.