Search

International audience; The p-type Ge-doped (0, 1, 4 and 7 at.%) Mg

In this paper, the corrosion behavior of Al-B4C nanocomposites made by stir casting is investigated. The corrosive environments included 0.1 M HCl, 0.6 M NaCl, 0.03 M H3BO3, and 2 M NaOH solutions. Both the optical microscopy and the field emission scanning electron microscopy methods were used for the microstructural investigation. The X-ray diffraction and the energy dispersive spectroscopy techniques were utilized to detect phases. Tafel polarization results showed that the corrosion rate for the Al-B4C nanocomposites reduced by about 94.0 -99.7% in comparison with the aluminum alloy in 0.1 M HCl and 0.6 M NaCl solutions; however, this decrease was 20.4 - 57.1% in 0.03 M H3BO3 solution. Moreover, the electrochemical impedance spectroscopy results demonstrated that for nanocomposites the total increase in the charge transfer resistance increased to 80.7% compared to the aluminum alloy in 0.1 M HCl solution after 72 h. The Al-B4C nanocomposite that was stirred for 6 mins at 8000C exhibited higher corrosion resistance than other samples after 72 h in 0.6M NaCl. However, the sample suggested for all utilized corrosive solutions was the nanocomposite made at 750 0C and stirred for 6 mins, based on the lower crystallite size of a-Al phase.

This study was conducted to investigate the effects of sintering conditions on the phase composition, microstructure, and physico-mechanical properties of the bauxite-based low-cement refractory castables. For this purpose, the specimens were sintered at various temperatures (1350-1450 °C) and heating rates (3-10 °C/min). Results showed that the sintering conditions have a remarkable effect on the physico-mechanical properties of the refractory castables. The mechanical strength was considerably increased by increasing the heating rate from 3 to 10 °C/min which was attributed to lower amounts of porosity and higher amount of the platy crystals of CA6 phase. The lower porosity of the specimens sintered at lower temperature with 10 °C/min of heating rate also resulted in the higher mechanical strength. The results obtained in this study showed a negative linear relationship between the cold crushing strength and porosity of the specimens with a high degree of measurement conformity.

In this study, bulk and thin films of the Pr and Ce co-doped yttrium iron garnet, Pr0.5CexY2.5-xFe5O12, with various contents of Ce, x=0.25, 0.5 and 0.75, were synthesized and investigated. The solid-state method was used to synthesize the bulk samples and the films were deposited by the Pulsed Laser Deposition (PLD) method. The phase and structure analysis of the samples were investigated by the XRD, SEM, and AFM techniques. The results show that the bulk samples contain the secondary phases of cerium oxide (CeO2) and iron oxide (Fe2O3). After deposition, a single garnet phase is formed in the (444) orientation on GGG (111) substrate. The investigation of the magnetic properties was undertaken by VSM. The results of the VSM manifested the positive impression of the additives on the saturation magnetization from 33.47 e m u g in the un-doped sample to 37.07 e m u g in the sample containing 0.25 mol of Ce. The saturation magnetization plunged to 25.39 e m u g in a sample involving 0.75 mol of Ce due to the forming of the secondary phases. In order to find the co-dopant effect on the magneto-optical properties, the Faraday rotation of the films was measured. The Faraday rotation of the samples was found to be 0.74, 0.82 and 1.24 d e g μ m for x= 0.25, 0.5 and 0.75, respectively. Comparing the results with the literature manifests the synergistic effect of the two additives.

In the current work, high density polyethylene (HDPE) composites were fabricated via Friction Stir Processing (FSP). A two-phase Fe-Fe3O4 powder was used as the reinforcing agents. The extremely low cost powder was obtained from shot-blasting of as-forged low carbon steel components. X-ray diffraction (XRD) was used to phase analysis and evaluation of the purity of the as-received powder. The size distribution of the powder was determined by Laser Particle Size Analysis (LPSA). Also, Scanning Electron Microscopy (SEM) was employed to investigate the particles morphology. The processing used a cylindrical tool to impose the severe plastic deformation and material stirring in order to improve the mechanical properties and particles distribution. The tribological and mechanical properties of the fabricated samples were examined. According to the results, both the friction coefficient and specific wear rate of FSPed samples reduced remarkably. The hardness and tensile strength of the FSPed composites were higher than the FSPed HDPE samples; however, their elongations were lower.

Herein, intrinsic p-type conductivity of NiO films were enhanced by high power impulse magnetron sputtering (HiPIMS) technology, where more charged Ni3+ ions are created during the deposition process. The formation of Ni3+ ions are advantageous for strengthening the p-type conductivity of NiO films. As the pulse off-time increases from 0 μs to 3000 μs, Ni3+ concentration improves greatly, indicating the amount of Ni vacancies as well as the hole concentration significantly enhances. It confirms that HiPIMS is a preferential technology for preparing NiO films with high p-type conductivity. Especially, when pulse off-time reaches 3000 μs, a high carrier concentration of 2.86 × 1021 cm−3 and a relatively low electrical resistivity about 0.07 Ω·cm are achieved.

TaC/a-C:H films with varying carbon content within a narrow window were deposited employing HiPIMS in the Ar/C2H2 atmosphere. The DC deposited TaC/a-C:H reference films were prepared under the same deposition parameters for comparison. Analysis and comparison of the chemical bonding state, structure, mechanical and tribological properties, and oxidation resistance of the films were conducted, with the aim of emphasizing the differences in the nanocomposite structure and properties of the films correlated to deposition conditions. It reveals that the HiPIMS deposited TaC/a-C:H films outperform the DC deposited ones, exhibiting higher hardness and toughness, lower friction coefficient and wear rate, and stronger oxidation resistance. The improved performances in HiPIMS are attributed to HiPIMS plasma, which enables (i) the volume fraction of crystalline TaC phase and amorphous carbon phase, (ii) the stoichiometric ratio and grain size of the crystalline phase, (iii) the sp2/sp3 –C ratio, and (iv) the residual stress to develop in the manner that is conducive to film properties. It is demonstrated that HiPIMS plasma can be used as an effective means to modulate the chemical bonding state and nanocomposite structure of TaC/a-C:H film for achieving higher performance in terms of hard yet tough, wear and oxidation resistance.

ZnO/In2O3 composite nanofibers were fabricated by electrospinning method and effects of process parameters on the distribution and mean diameter of synthesized NFs were investigated. Electrospinning process followed by post calcination was performed at two different temperatures to optimize the synthesis condition of ZnO and In2O3 NFs. Thermal Analysis was done on electrospun fibrocomposites to find calcination temperatures. Electrospinning parameters (Tip to Collector Distance (TCD), feeding rate, and applied voltage), which led to a uniform distribution and thinnest NFs, were used for synthesizing ZnO/In2O3 composite in the co-electrospinning process. Structural, morphological, and chemical studies were also carried out on the NFs. TCD increment led to the improvement of diameter distribution and homogeneity of synthesized NFs. Low voltages (below 20 kV) resulted in thinner fibers without appearing any remarkable beads defect and the optimum feeding rate was found to be 1 ml/h. For further application of NFs in gas sensors, well distributed thinnest fibers were obtained.

Metallic platinum&ndash, titanium coatings were deposited by co-sputtering of two metallic Pt and Ti targets in pure argon atmosphere. The titanium concentrations varied from 0 to 47 atomic percent and were adjusted as a function of the current applied to the titanium target. The structural and chemical features of these films were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All as-deposited coatings exhibit a perfect covering of the alumina pellets&rsquo, substrate surface. The coatings containing more than 4 at.% Ti are amorphous, whereas the others crystallize in the face-centered cubic (fcc) structure of platinum. After an annealing treatment under air for 2 h, all of the coatings adopt the fcc structure with a crystallization temperature depending on the titanium content. For titanium concentrations higher than 32 at.%, the TiO2 phase appears during the annealing treatment. For the smaller film thickness of Pt&ndash, Ti alloys (15 nm), the Ostwald ripening mechanism is observed by SEM increasing the annealing temperature regardless of the content of Ti. The film resistivity measured at room temperature is lower than 7 10&minus, 4 &Omega, &middot, cm and increases with the temperature to achieve an insulating behavior (in air and reducing atmosphere Ar-H2 (90-10) at 1123 K the resistivity is &rho, 10+36 &Omega, cm). When the thickness of intermetallic Pt3Ti layer is higher than 50 nm, the coating is continuous and the resistivity is below 5 10&minus, cm in air and in reducing atmosphere (Ar with 10% of H2) up to 1273 K.

Tungsten oxide thin films are grown by DC reactive magnetron sputtering combining glancing angle deposition (GLAD) and reactive gas pulsing process (RGPP). Inclined, zigzag and spiral columnar architectures are produced with various oxygen injections during the growth. The dodecane and ozone sensing properties of these tungsten oxide nanostructured active layers are comparatively studied with that of films deposited by conventional sputtering process. Microstructure, morphologies and electrical behaviors are characterized as a function of the growing conditions. As-deposited films systematically exhibit an amorphous crystal structure with a porous microstructure, which depends on the GLAD architecture. Annealing at 300 °C in air for 12 h leads to a polycrystalline structure keeping voided networks. Dodecane and ozone sensing performances are the most significant for inclined columnar architectures but they also depend on the RGPP sputtering conditions. As a result, the GLAD + RGPP combination proves to be a relevant strategy for the fabricating tungsten oxide nanostructured films as active layers with an attractive potential for gas sensors.

International audience; Tungsten oxide thin films were prepared by DC magnetron sputtering. The reactive gas pulsing processwas implemented to modify tungsten and oxygen concentrations in the films. A rectangular pulsingsignal was used with a pulsing period fixed at P ¼ 16 s, whereas the duty cycle a was systematicallychanged from a ¼ 0e100% of P. The chemical composition of the films showed a gradual increase ofoxygen-to-tungsten concentrations ratio from 0 to more than 3.0 as a function of the duty cycle. Filmsbecame poorly crystallized and even amorphous with an increase of the oxygen content. Similarly, atypical columnar structure was observed for pure or oxygen-rich tungsten films, which vanished whenthe duty cycle was higher than a few % of P. The optical transmittance in the visible range of WOx filmsdeposited on glass also showed a progressive change from absorbent to transparent as the duty cycle wasincreased. Electronic transport properties including conductivity, carrier mobility and concentration alsodemonstrated the controlled and regular evolution of the electrical properties from metallic to insulatorwhen the duty cycle and thus oxygen concentration in the films changed from pure tungsten to overstoichiometricWO3 compound.

In this study, nanoporous BiVO4 thin films were deposited using reactive direct-current (DC) magnetron sputtering. The effects of thickness on the film morphology, crystal structure, microstructure, composition, optical and photocatalytic properties under visible light were investigated. The film porosity and refractive index were also determined via the UV-Vis spectrophotometric technique using transmittance and reflectance spectra and Cauchy dispersion law as the fitting model. The nanoporous morphology was observed using field-emission scanning electron microscopy (FESEM) with average pore sizes in the 20–40 nm range. The X-ray diffraction (XRD) results showed different texture grades corresponding to the (040) crystallographic plane, establishing the film thickness influence on the preferential orientation. The X-ray photoelectron spectroscopy (XPS) was also implemented to investigate the chemical state of the film surface, as well as to determine the valence band position. The film 715 nm in thickness showed the highest porosity (52%), narrowest bandgap (2.44 eV), highest exposed (040) crystallographic plane and highest visible-light-driven photodegradation towards Rhodamine-B (RhB) solution. The pH of the solution also impacted the RhB photodegradation which was optimum at pH 3 with chromophore cleavage pathway dominance, whereas at neutral pH it had distinctively slow kinetics probably due to poor electrostatic interactions and the N-deethylation kinetics bottleneck. The photocatalytic cycle experiments exhibited high stability and recyclability of BiVO4 thin-film photocatalysts after four cycles (4 × 7 h) of exploitation. The photocatalytic mechanism was determined using scavengers and the significance of hydroxyl radicals and photogenerated holes were established. The photocatalytic activity reached 97% after 7 h of illumination with a 400 W light source.

Purpose A self-lubricant surface composite including Al matrix and Babbitt alloy 11 reinforcement has been fabricated via friction stir processing (FSP). Design/methodology/approach The optimum processing condition is estimated by statistical analysis of a L9 Taguchi design of experiment. The results of Taguchi analysis suggested four passes of FSP, traverse speed of 40 mm/min and rotational speeds of 1,250 rpm as the optimum parameters to achieve higher hardness and wear resistance. Findings The needle-shaped particles are fragmented into the finer particles after FSP. There is uniform distribution of precipitations after FSP. The microhardness of manufactured surface bearings has been increased. Finer particles, smaller grains and in situ formed intermetallic precipitations (AlSb) can be responsible for hardness enhancement. Wear resistance of base metal also has been remarkably enhanced after FSP. Originality/value The originality of this paper lies in the following: new self-lubricating surface composite; a tough and resistant to wear sheets; and using a solid-state method to fabricate a surface bearing.

In the present research, multi-pass friction stir processing (FSP) was employed for the first time to disperse graphene in the form of graphene nano-platelets (GNPs) into an AA5052 aluminum‑magnesium alloy to fabricate a new Al-Mg/3 vol% GNPs nanocomposite. After five cumulative FSP passes, the GNPs were distributed within the metal-matrix. Field emission-scanning (FE-SEM) and transmission electron microscopy (TEM) analyses were used to examine the dispersion of GNPs, and suggested negligible deterioration of the graphene planar structure following FSP. Some clusters of graphene originating from the initial powder remained due to the high surface energy of these GNPs, while grain orientations were evaluated in the nanocomposite using electron back scattering diffraction (EBSD). A fine equiaxed recrystallized grain structure with an average size of 2.1 μm was formed in the stir zone (SZ) after FSP while dispersing GNPs. Indentation revealed the hardness of the nanocomposite increased by 53% compared to the processed Al-Mg alloy. Yield strength also was improved by more than three times while preserving ductility which achieved 20% strain before fracture. Fractographic studies of tensile test specimens revealed a mixed ductile-brittle fracture behavior. Based on the micromechanics theory, three models considering the microstructural parameters (i.e., aspect ratio, mean size, and volume fraction of GNPs, grain size, and clustering during process) were developed to predict the strengthening effects of GNPs in the terms of elastic modulus, yield strength, and indentation hardness. Correlation between these predicted values and experimental data are discussed in detail.

As machine tool coating specifications become increasingly stringent, the fabrication of protective titanium aluminum nitride (Ti-Al-N) films by physical vapor deposition (PVD) is progressively more demanding. Nanostructural modification through the incorporation of metal dopants can enhance coating mechanical properties. However, dopant selection and their near-atomic-scale role in performance optimization is limited. Here, yttrium was alloyed in multilayered Ti-Al-N films to tune microstructures, microchemistries, and properties, including mechanical characteristics, adhesion, wear resistance, and resilience to oxidation. By regulating processing parameters, the multilayer period (Λ) and Y content could be adjusted, which, in turn, permitted tailoring of grain nucleation and secondary phase formation. With the composition fixed at x = 0.024 in (Ti0.6Al0.4)1–x Y x N and Λ increased from 5.5 to 24 nm, the microstructure transformed from acicular grains with 〈111〉 preferred orientation to equiaxed grains with 〈200〉 texture, while the hardness (40.8 ± 2.8 GPa to 29.7 ± 4.9 GPa) and Young’s modulus (490 ± 47 GPa to 424 ± 50 GPa) concomitantly deteriorated. Alternately, when Λ = 5.5 nm and x in (Ti0.6Al0.4)1–x Y x N was raised from 0 to 0.024, the hardness was enhanced (28.7 ± 7.3 GPa to 40.8 ± 2.8 GPa) while adhesion and wear resistance were not compromised. The Ti-Al-N adopted a rock-salt type structure with Y displacing either Ti or Al and stabilizing a secondary wurtzite phase. Moreover, Y effectively retarded coating oxidation at 1073 K (800 °C) in air by inhibiting grain boundary oxygen diffusion.

Friction stir processing (FSP) which imposes severe plastic strains has been used as a solid-state process to refine the grain structure of a Mg-Al-Zn alloy and therefore to enhance the strength and wear resistance without significant reduction of ductility. The introduced stepped tools result in more uniform microstructure, and therefore higher mechanical properties, as well as enhanced wear resistance. More passes of FSP could lead to more uniform microstructure and finer grains. The grain size was reduced from above 40 µm to below 4 µm. The pin root hole defect is also reduced during FSP by the stepped tools especially by cylindrical one. Microhardness was increased more than two times compared with the as-received sample. The tensile strength and elongation are almost doubled after different conditions of FSP. Coefficient of friction is reduced to 1/13.3, and weight loss has been reduced to about 50% of initial values after friction stir processing. The obtained results also demonstrated the successful dynamic recrystallization during FSP.

Pure V thin films were dc sputtered with different pressures (0.4 and 0.6 Pa) and particle incident angles α of 0°, 20° and 85°, by using the GLancing Angle Deposition (GLAD) technique. The sputtered films were characterized regarding their electrical resistivity behaviour in atmospheric pressure and in-vacuum conditions as a function of temperature (40–550 °C), in order to control the oxidation process. Aiming at comprehending the oxidation behaviour of the samples, extensive morphological and structural studies were performed on the as-deposited and annealed samples. Main results show that, in opposition to annealing in air, the columnar nanostructures are preserved in vacuum conditions, keeping metallic-like electrical properties.

The purpose of this paper is to investigate the microstructural and corrosion behaviors of Al–B4C nanocomposites fabricated by the stir casting technique. Two parameters included the stirring time and temperature have changed in the manufacturing process to affect the characteristics of nanocomposites. Both the optical microscopy (OM) and the field emission scanning electron microscopy (FESEM) were utilized for microstructural evaluations. Moreover, the X-ray diffraction (XRD) and the energy dispersive spectroscopy (EDS) methods were used to identify various phases and to study the elemental analysis of specimens, respectively. In addition, the polarization and electrochemical impedance spectroscopy (EIS) techniques were employed to peruse the corrosion properties of fabricated nanocomposites in various corrosive environments. The FESEM images showed that B4C nanoparticles were distributed uniformly in the aluminum matrix. Polarization test results demonstrated that the corrosion rate of Al–B4C nanocomposites decreased to lower than 99% compared to the aluminum alloy in 0.6 M NaCl solution; however, such a reduction was about 22–42% in 2 M NaOH solution. The EIS test results depicted that the total increase in the charge transfer resistance values for Al–B4C nanocomposites was about 23–59% with respect to the aluminum matrix in 0.1 M HCl solution. Regression analysis results displayed that for acidic solutions (such as HCl and H3BO3) the stirring temperature was more effective than the stirring time to reduce the corrosion rate.

In this Study, the effects of substitution of Y3+ by Dy3+ ions on the crystal structure and magnetic properties for Y2.8-xDyxCe0.10Bi0.10Fe5O12 (x = 0.0, 0.2, 0.4, 0.6) and pure yttrium iron garnet (YIG) produced by conventional method have been investigated. The Fe2O3, Y2O3, CeO2 and Dy2O3 powders were mixed in stoichiometric ratio and annealed at different temperatures from 1000 to 1420 °C in air atmosphere. At the final stage, Bi2O3 was aggraded in the YIG and annealed in 1000 °C in an air atmosphere. The phase structure, morphology and magnetic properties were investigated using Raman Spectroscopy (RS), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM), respectively. The X-ray diffraction data showed a nearly pure and single-phase of doped garnet with small amounts of CeO2 secondary phase. The RS result reveals the characteristic peak of the YIG structure. The XPS analysis indicates that bismuth, dysprosium, yttrium and iron ions exist in their corresponding “+3” valence states whereas cerium finds in “+3” and “+4”. The saturation magnetization augments from 33.47 emu/g for pure YIG to 35.15 emu/g for xDy = 0.2 due to the small increase in d-p wave function overlap between the octahedral Fe3+ ion and intervening oxygen ion. The coercivity values decrease from 20.16 Oe for pure YIG to 17.78 Oe for xDy = 0.6. The improved magnetic properties promote the doped garnets to microwave absorption and sensing applications.

Lanthanum perovskites are promising candidates to replace platinum group metal (PGM), especially regarding catalytic oxidation reactions. We have prepared thin catalytic coatings of Sr and Ag doped lanthanum perovskite by using the cathodic co-sputtering magnetron method in reactive condition. Such development of catalytic films may optimize the surface/bulk ratio to save raw materials, since a porous coating can combine a large exchange surface with the gas phase with an extremely low loading. The sputtering deposition process was optimized to generate crystallized and thin perovskites films on alumina substrates. We found that high Ag contents has a strong impact on the morphology of the coatings. High Ag loadings favor the growth of covering films with a porous wire-like morphology showing a good catalytic activity for CO oxidation. The most active composition displays similar catalytic performances than those of a Pt film. In addition, this porous coating is also efficient for CO and NO oxidation in a simulated Diesel exhaust gas mixture, demonstrating the promising catalytic properties of such nanostructured thin sputtered perovskite films. Fil: Arab Pour Yazdi, Mohammad. Universite de Bourgogne; Francia Fil: Lizarraga, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Bionanociencias "Elizabeth Jares Erijman"; Argentina. Universite Claude Bernard Lyon 1. Institut de Physique Nucléaire de Lyon.; Francia. Universite Lyon 2; Francia Fil: Vernoux, Philippe. Universite Claude Bernard Lyon 1. Institut de Physique Nucléaire de Lyon.; Francia. Universite Lyon 2; Francia Fil: Billard, Alain. Universite de Bourgogne; Francia Fil: Briois, Pascal. Universite de Bourgogne; Francia

International audience; Mg-Sn thin films (21 ≤ at. % Sn ≤ 42.5) were deposited by magnetron sputtering in the argon atmosphere. The structure and morphology of the films were characterized as a function of the composition. Mg2Sn structure was changed from stable face-centered cubic to metastable orthorhombic structure while the content of Sn in the films increased. The influence of this structural modification on thermoelectric properties was discussed in a wide range of temperatures (30–200 °C). The film carrier concentration and mobility were measured to explain the electronic transport behavior as a function of the film structural modifications. The maximum figure of merit ZT ≈ 0.26 at 200 °C was reached for the film with 36 at. % Sn while a mixture of cubic and orthorhombic Mg2Sn structures coexisted. An annealing treatment was performed under vacuum (∼10−4 Pa) at different temperatures (up to 600 °C) to determine the limit of structural and morphological stability of this film.

Inclined, zigzag and spiral Ti1-xCux films were co-sputtered by the Glancing Angle Deposition technique. Two distinct titanium (Ti) and copper (Cu) targets were used and the films were grown with a particle flow incidence angle α of 80°. The thin films had Cu contents ranging from 36 to 76 ± 5 at. %. The effect of increasing Cu incorporation on the electrical anisotropy, as well as the effect of columnar architecture variations on the morphological, structural and electrical properties of the films was evaluated and correlated with the particular their architectures. Main results show well-defined and highly inclined columns (with an average column angle β = 45° ± 5°) for all sputtering conditions. Quasi-amorphous thin films were obtained with low Cu contents (36 at. %), while crystalline Cu (111) + Ti3Cu (114) bi-component structures were achieved at high Cu concentrations (76 at. %). No permanent oxidation of the films was detected after a two-cycle RT-200 °C-RT (RT – room temperature) annealing in air. The two-dimensional representation of the resistivity anisotropy of the columnar and 2 zigzags films is shaped as an elongated ellipse along the xx direction, with a variation of the effective anisotropy, Aeff, at 200 °C from 1.4 to 2.9. The samples prepared with 2 spirals and the same Cu content (36 at. %) exhibit an isotropic behavior, with an Aeff value at 200 °C of 1.1. The overall results demonstrate the possibility to tune the thin films' morphology and electrical characteristics in order to obtain a set of properties that are suitable for the development of high performance materials, such as the case of resistance temperature detectors., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. Funding was also provided by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION Program (contract ANR-11-LABX-01-01). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged.

International audience; Tungsten oxide thin films exhibiting an oriented columnar architecture were prepared by reactive co-sputtering. Two opposite W and WO3 targets focused on the center of the substrate were simultaneously sputtered using opposite and oblique angles of 80° from the substrate normal. The reactive gas pulsing process was used to adjust the films electrical resistivity. Different inclined columnar structures were produced and applied as gas sensors for dodecane detection. Morphology, structure and resistivity of the films were investigated and connected to the sensing performances measured from 373 to 773 K.

International audience; Hydrogen solid storage in intermetallic compounds has attracted great attention in the recent decades; TiFe-basedmetal hydride is one of the most important candidate materials to hold atomic hydrogen because of its significant storage capacity (about 1.9 wt. %) and its moderate operating pressure and temperature. The main hindrance to an effective and large use of this metal forming hydride is the difficult activation process i.e. the initial hydriding attempt. In this paper an experimental study about the first hydrogenation process of TiFe0.9Mn0.1 is carried out with a Sievert apparatus. At first, powder fabrication protocol then materials and methods used for the experimental characterizations are described. Secondly, a literature survey is presented about the activation processes of TiFe based alloys. Finally experimental results, discussions and conclusions are exposed. Those results lead to a comparison between the hydrogenation behaviors of two TiFe0.9Mn0.1 powder types: the ‘as received’ powder and the same powder after a thermo-chemical treatment. A wide improvement in the hydrogen activation response is noticed when the powder is submitted to this thermo-chemical treatment under specific operating conditions of gas pressure, temperature and time-duration. Plotted PCI curves and XRD patterns demonstrate that the material bulk is not affected by this thermo-chemical treatment. Then, the operating conditions are optimized, and SEM visualizations are performed in order to point out the effects of the treatment on the surface properties of TiFe0.9Mn0.1 particles. At the end, a conclusion summarizes the main results and outlines the perspectives of such thermo-chemical treatment.

ZnO with dense, porous, nano-wire and nano-tree morphologies was successfully synthesized via reactive magnetron sputtering at high pressure (10 Pa) and with different deposition temperatures (RT → 1273 K). The morphological properties of prepared ZnO coatings were revealed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis was performed to determine crystalline structure of the films in relation with their deposition temperature. Hall effect measurements were used to investigate the electrical resistivity, free carrier concentration and mobility in the coatings as a function of their morphology in a temperature range from 293 K to 473 K. Finally, C12H26 dodecane gas sensing properties of ZnO nano-trees were investigated at different temperatures (from 323 K to 566 K) and the results were discussed depending on dodecane concentration. A remarkable response of 39% was observed at 415 K for a low concentration of dodecane in air [1 ppm(v)]. High response to low concentrations of C12H26 as well as good chemical stability of ZnO nano-trees make this kind of structure a potential candidate as sensing layer for practical sensor applications.

Équipe 101 : Nanomagnétisme et électronique de spin; International audience; Zn1-xCoxO (0 < x < 0.146) conductive thin films have been deposited by reactive magnetron sputtering of metallic Zn and Co targets at high pressure and temperature. The structural properties have been investigated by using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It has been observed that all as-deposited films are crystallized in pure hcp ZnO structure and neither traces of metallic nor oxide Co-rich clusters were detected. The average grain size estimated from full width at half maximum of XRD results varied between 65 and 83 nm. XPS analyses exhibit that Co ions are successfully entered into ZnO lattice as Co. The electrical properties including conductivity, carrier density and carrier mobility were determined by Hall effect measurements in a temperature range from 300 K to 475 K. The conductivity of the films decreases from sigma(300K) = 2.2 x 10(4) to 2.3 x 10(-1) Sm-1 as the Co content changes from 0 to 0.146. Magnetic measurements reveal the absence of ferromagnetism even at 3 K and a paramagnetic Curie-Weiss behavior associated to magnetic clusters.

In this study, chopped and attrition milled high strength carbon, E-glass, and S-glass fibers have been used as the reinforcing agents in an aluminum alloy (Al1100) considered as the matrix. The Surface Metal Matrix Composites (SMMCs) then are produced by Friction Stir Processing (FSP). Tensile and micro-hardness examinations represent a magnificent improvement in the hardness, strength, ductility and toughness for all of the processed samples. Scanning Electron Micrographs reveal a proper distribution of the reinforcements in the matrix and a change in the fracture behavior of the FSPed specimens. The synergetic effects of reinforcing by fibers and Severe Plastic Deformation (SPD) lead to an extra ordinary improvement in the mechanical properties.

International audience; wo series of W-Cu thin films were developed by the GLAD co-sputtering technique. The films were produced with two separated W and Cu targets. Both targets were focused on the centre of the substrate and were simultaneously sputtered using opposite and oblique angles of 80° from the substrate normal. In the first series, the W and Cu target currents were inversely changed from 50 to 140. mA in order to tune the elemental concentrations and the microstructure. For the second series, a shield was added between W and Cu targets, perpendicularly to the substrate surface in order to prevent the cross-contamination of the targets. The target currents were varied similarly to the first series. Two argon sputtering pressures were used (0.42 and 1.0. Pa) in each series, with and without the shield.Microstructure showed a tuneable inclined columnar microstructure, which become normal to the substrate at high pressure. The crystallographic structure was not significantly influenced by the shield implementation but rather by the sputtering pressure. The W/Cu atomic concentration ratio varied between 0.2 and 5.5 as a function of the sputtering pressure and target currents and an anisotropic chemical composition was measured inside the columns. The wide range of DC electrical resistivities (3.6×10⁻⁷ to 5.7×10⁻⁵ Ωm) was discussed considering W and Cu target currents, high and low sputtering pressures and the use of a cross-contamination shield. The role of the microstructure was clearly shown since significantly higher resistivity was obtained at high pressure, as a function of the W/Cu atomic concentration ratio. W-Cu sputtered thin films grown at... (PDF Download Available). Available from: https://www.researchgate.net/publication/320080270_W-Cu_sputtered_thin_films_grown_at_oblique_angles_from_two_sources_Pressure_and_shielding_effects [accessed Apr 09 2018].

Mg&ndash, Si thin films (23 &le, at.% Si &le, 43) were deposited by co-sputtering of Mg and Si targets in an argon atmosphere. Two groups of samples were prepared with respect to sputtering parameters. The first Group I was synthesized while residual pressure in the reactor was lower than 7 &times, 10&minus, 4 Pa and the second Group II when reactor was pumped down to pressure higher than 7 &times, 4 Pa. The Mg2Si phase appeared for all as-deposited films of Group I around the stoichiometric composition region (29 &le, 37) and in the Mg-rich region (at.% Si &lt, 29) the Mg2Si and Mg phases coexisted. An amorphous structure was obtained for all as-deposited films of Group II no matter their composition (34 &le, 38) and the Mg2Si structure was achieved after post annealing under air at temperature &ge, 140 &deg, C. Thermal stability of Mg2Si thin films was investigated by annealing treatments under air. Superficial Mg2Si structural decomposition began at T &gt, 500 &deg, C and layer morphology and structure damaged while annealing temperature increased up to 700 &deg, C. The films&rsquo, electrical resistivity, free carrier concentration and mobility as well as Seebeck coefficient were measured and thermoelectric power factors were discussed vs. composition.

Inclined, zigzag and spiral TiAg films were prepared by glancing angle co-deposition, using two distinct Ti and Ag targets with a particle incident angle of 80 degrees and Ag contents ranging from 20 to 75 at%. The effect of increasing Ag incorporation and columnar architecture change on the morphological, structural and electrical properties of the films was investigated. It is shown that inclined columnar features (beta = 47 degrees) with high porosity were obtained for 20 at% Ag, with the column angle sharply decreasing (beta = 21 degrees) for 50 at% Ag, and steeply increasing afterwards until beta = 37 degrees for the film with 75 at% Ag. The sputtered films exhibit a rather well-crystallized structure for Ag contents >= 50 at%, with a TiAg (111) preferential growth. No significant oxidation was detected in all films, except for the one with 20 at% Ag, after two 298-473-298 K temperature cycles in air. The calculated temperature coefficient of resistivity (TCR) values vary between 1.4 and 5.5 x 10(-4)K(-1). Nano-sculptured spiral films exhibit consistently higher resistivity (rho = 1.5. x 10(-6) Omega m) and TCR values (2.9 x 10(-4)K(-1)) than the inclined one with the same Ag content (rho = 1.2 x 10(-6) Omega m and TCR = 2.0 x 10(-4)K(-1)). No significant changes are observed in the zigzag films concerning these properties. The effective anisotropy A(eff) at 473 K changes from 1.3 to 1.7 for the inclined films. Spiral films exhibit an almost completely isotropic behavior with A(eff) = 1.1. Ag-rich TiAg core + shell Janus-like columns were obtained with increasing Ag concentrations., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. Funding was also provided by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION program (contract ANR-11-LABX-01-01). Financial support from the Basque Government Industry Department under the ELKARTEK program is also acknowledged., info:eu-repo/semantics/publishedVersion

CuCr 0.93 Mg 0.07 O 2 thin films were successfully deposited by DC reactive magnetron sputtering at 1123 K from metallic targets. The influence of film thickness on the structural and optoelectronic properties of the films was investigated. X-ray diffraction (XRD) results revealed that all the films had a delafossite structure with no other phases. The optical and electrical properties were investigated by UV–VIS spectrophotometer and Hall measurement, respectively. It was found that the optoelectronic properties exhibited a thickness-dependent behavior. The optical band gap and the average transmittance of the films showed a monotonous decrease with respect to the increase in thickness. The average transmittance in the visible region decreased from 67% to 47% as the thickness increased from ~70 nm to ~280 nm. Simultaneously, the conductivity of the films fell from 1.40 S∙cm −1 to 0.27 S∙cm −1 . According to Haacke's figure of merit (FOM), a film with a maximum FOM value of about 1.72×10 −7 Ω −1 can be achieved when the thickness is about 70 nm (σ≈ 1.40 S·cm −1 and T av. ≈67%).

Among the various Severe Plastic Deformation (SPD) processes, Equal Channel Angular Pressing (ECAP) is one of the most applicable one which improves strength and ductility due to grain refinement and suitable texture development. In this study, cold rolling were carried out on the 4 pass ECAPed (in route A and C) strip shaped specimens of AZ31 magnesium alloy to investigate the ECAP effects on the roll-ability. Results showed that reduction in area which can be concerned as an index for roll-ability increased after ECAP. It was also seen that ECAP in route C enhanced roll-ability more than route A.

In this paper, we investigate the feasibility of La1-xAgxCoO3-α nanowires by reactive magnetron sputtering. After a short description of the experimental and hydrocarbon sensing bench devices, a first part will be dedicated to the chemical, microstructural and structural characterization (SEM, XRD,...) of the coatings. As deposited coatings are amorphous and a post heat-treatment under air at 873 K is necessary to crystallise them in the perovskite structure. Finally, the performance as dodecane-sensors of these coatings with amorphous and crystalline structures will be discussed depending on dodecane concentrations and sensitive surfaces temperature and will be compared to those of La0.40Sr0.15Ag0.45CoO3-α nanowires.

Equal Channel Angular Pressing (ECAP) is one of the most applicable Sever Plastic Deformation (SPD) processes which leads to strength and ductility improvement through the grain refining and development of a suitable texture. In this study, after designing and manufacturing a suitable die, 4 pass ECAP process at route C is done on strip shaped specimens of AZ31 magnesium alloy in order to achieve desirable microstructural and mechanical properties. Microstructure then got studied through the optical microscopy. Results show that mean grain size is decreased and grain size distribution got close to normal distribution state by increasing the pass number. However, the grain size is reduced by increasing of ECAP temperature.

Zn1-xCoxO (0 < x < 14.6) diluted magnetic semiconductor coatings have been obtained by reactive DC magnetron sputtering of metallic Zn and Co targets at high pressure and high temperature. The coatings structural properties have been investigated by X-ray diffraction. All as-deposited coatings are crystalized in ZnO structure and neither traces of metallic nor oxide Co-rich clusters were detected in the films. The temperature dependence of the magnetization shows a paramagnetic Curie-Weiss behavior with antiferromagnetic interaction due to the associated spins and simple paramagnetic curie behavior of isolated free spins.

This paper reports results of dodecane-sensing studies with double-substituted LaCoO3perovskite oxide nanowires. La0.40Sr0.15Ag0.45CoO3-αnanowires were co-sputtered from metallic La, Sr, Ag and Co targets in the presence of a reactive argon-oxygen gas mixture. As deposited coatings are amorphous and crystallise in the perovskite structure after annealing at 873 K for 2 hours under air. Electrical response of the La0.40Sr0.15Ag0.45CoO3-αnanowires was measured at different temperature under air and under air containing 1 to 100 ppm (v) of dodecane vapour. The electrical signal of the nanowires was found to be high and it was possible to detect low concentrations of dodecane (under 5 ppm (v) ) at 573 K.

Cu x O thin films were deposited on glass and silicon substrates by High Power Impulse Magnetron Sputtering (HiPIMS) at room temperature from a metallic copper target. The influence of pulse off-time on the films’ structural, morphological and optoelectronic properties was investigated. It was found that the power intensity applied on the Cu target was strongly affected by pulse off-time, which had an important impact on the films’ composition. Upon increasing the pulse off-time from 500 μs to 3500 μs (pulse on-time fixed at 50 μs), the films’ crystallinity as well as transmittance in the visible region both ameliorate. Meanwhile, the conductivity type changed from n-type to p-type as the films’ composition changed. When the pulse off-time was fixed at 2000 μs, the optimal p-type conductivity of about 3 S × cm −1 was achieved, which is the highest p-type conductivity reported for Cu 2 O films in the last few years. The transition of the films’ conductivity type can be utilized for the fabrication of Cu 2 O-based p-n homojunction, and may also prove useful in developing other oxide films by using HiPIMS technology.

International audience; The optoelectronic properties of Mg-doped CuCrO2 with delafossite structurewere enhanced by stacking CuCr0.93Mg0.07O2/Ag/CuCr0.93Mg0.07O2 multilayers.The influences of the deposition time of the Ag and the thickness of theCuCr0.93Mg0.07O2 layers on the film’s performance were investigated. When thestacks were deposited under our deposition conditions, no continuous Ag layerwas observed. The diffusion of Ag atoms into the neighboring CuCr0.93Mg0.07O2layers caused a composition gradient of Ag in the films and caused Cr3? cationsto be replaced by Ag? cations, which is beneficial for improving the conductivityof the films. When the Ag deposition time was increased, Schottky barriersoccurred between Ag nanocrystallites and CuCr0.93Mg0.07O2 grains, loweringthe films’ optoelectronic performances. The multilayers’ optoelectronic performanceswere enhanced when the thickness of the CuCr0.93Mg0.07O2 layers wasdecreased. Optimal films with a relatively high figure of merit of2.37 9 10-7 X-1 can be achieved when the deposition time of Ag and thethickness of CuCrO2:Mg layers are optimized.

International audience; W-Cu thin films were co-deposited by magnetron sputtering using the glancing angle deposition (GLAD) method. The deposition angle of W and Cu targets was fixed at 80°, and their currents were inversely and systematically changed from 50 to 140 mA. Scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction were used to investigate the morphology and the elemental composition of the films. Electrical properties were also studied by the van der Pauw technique. An increase of the W target current and a decrease of the Cu target produced an improvement of the inclined columnar and porous structure. The W-to-Cu weight concentration ratio was tuned from 0.68 up to 19. Wsingle bondCu films exhibited a diffracted signal corresponding to the (100) planes of the bcc tungsten structure for the highest W current intensities whereas the (111) peak due to the fcc copper phase was measured when the Cu target current increased. The dc electrical resistivity measured at room temperature was gradually changed from 3.59 × 10− 7 up to 9.90 × 10− 6 Ωm by means of an inverse variation of W and Cu target currents. The Cu-rich films exhibited a non-reversible resistivity vs. temperature evolution due to thermal oxidation whereas those co-sputtered with the highest W target currents showed a sudden increase of resistivity when the temperature was above 400 K.

Titanium films were DC sputtered with a particle flux incidence angle of 80 degrees, using the Glancing Angle Deposition (GLAD) technique with increasing sputtering pressures from 0.2 to 1.5 Pa. This range of pressures is typically implemented for the deposition of thin films by the magnetron sputtering process. The main objective of this work was to study the anisotropic electrical resistivity behaviour of the different thin film nanostructures that were obtained. It is shown that low sputtering pressures (0.2-0.5 Pa) promote higher column angles beta with respect to the substrate normal (15 degrees, This work was supported by the Region of Franche-Comte, the French RENATECH network and performed in cooperation with the Labex ACTION program (contract ANR-11-LABX-0101). Funding was also provided by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013 and project PTDC/EEI-SII/5582/2014. Armando Ferreira acknowledges the FCT for the SFRH/BPD/102402/2014 grant. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program., info:eu-repo/semantics/publishedVersion

International audience; The present study describes a sputtering and in situ vacuum electrical resistivity setup that allows a more efficient sputtering-oxidation coupling process for the fabrication of oxide compounds like vanadium dioxide, VO2. After the sputtering deposition of pure V thin films, the proposed setup enables the sample holder to be transferred from the sputtering to the in situ annealing + resistivity chamber without venting the whole system. The thermal oxidation of the V films was studied by implementing two different temperature cycles up to 550 °C, both in air (using a different resistivity setup) and vacuum conditions. Main results show that the proposed system is able to accurately follow the different temperature setpoints, presenting clean and low-noise resistivity curves. Furthermore, it is possible to identify the formation of different vanadium oxide phases in air, taking into account the distinct temperature cycles used. The metallic-like electrical properties of the annealed coatings are maintained in vacuum whereas those heated in air produce a vanadium oxide phase mixture.

There are demands to form nanolayered coating consisting of different materials in order to enhance the coating mechanical properties. However, poor structure control may lead to the formation of second phase and various defects. In this work, we endeavored to use cathodic arc deposition (CAD) method to fabricate TiN/Ti X Al 1 − X N nanolayered coatings with periods (Λ) ranging from 8 to 45 nm, which has great influences on coating microstructures and properties. X-ray diffraction (XRD), electron microscopy, nanoindentation and tribometry were employed to correlate coating microstructure and Λ with mechanical properties and wear resistance. The nanolayered coatings consisted of columnar grains with [111] texture, where individual grains contained low-angle grain boundaries without voids and amorphous phases. As Λ decreased, superlattices were generated, and reducing Λ from 45 nm to 13 nm yielded coatings with superior mechanical properties. The hardness peaked at 38.9 ± 3.6 GPa with a Young's modulus at 502.5 ± 40.4 GPa at 13 nm, however, when the Λ decreased to 8 nm the hardness and the Young's modulus deteriorated. It was concluded that wear resistance improved as the Λ decreased due to the greater interface population that impedes crack propagation.

Herein, a novel method of high-power impulse magnetron sputtering (HiPIMS) was used to prepare Cu2O thin films, which were deposited at ambient temperature without further thermal treatment. The films with varying optoelectronic properties as a function of oxygen flow ratio ( f O 2 ) were investigated. The results demonstrate that the film's performances are dependent on the film's composition and their crystallinity, which is influenced by the oxygen flow ratio. Cu2O-dominated films were fabricated in the oxygen flow range between 12.5% and 35%, whose values were used to determine their optoelectronic properties. Consequently, the films optoelectronic properties can be controlled by adjusting oxygen flow ratio. At low oxygen flow ratio ( f O 2 ≤ 10%), Cu-dominated films present n-type conductivity. With oxygen flow ratio increasing to above 15%, the films conductivity type changes from n-type to p-type due to the majority phase in the films changing from Cu to Cu2O. Meanwhile, the film's transmittance improves significantly from 0.28% for f O 2 of 2.5% to the maximum value of 58.77% for f O 2 of 30% resulting from the phase's transition upon increasing the oxygen flow ratio. When the oxygen flow ratio is at about 20%, a Cu2O film with optimal p-type conductivity of approximately 0.4 S × cm−1 is achieved at room temperature, which is the highest p-type conductivity reported in Cu2O film for the last few years.

BaCe0.8Zr0.1Y0.1O3-α protonic conductor coatings were co-sputter deposited from Ba, Zr and Ce0.9Y0.1 metallic targets in argon-oxygen reactive gas mixtures. The targeted composition of the coatings is obtain by fixing the discharge current applied on Zr and Ce0.9Y0.1 targets and adjusting the discharge current applied on Ba target. As deposited coatings are amorphous and present a good chemical stability against carbonation under air up to 573 K. The coatings crystallise after annealing treatment around 873 K for 2 hours under air in a mixture of BaCO3 and CeO2 in spite of the targeted double substituted BaCeO3 perovskite structure. Nevertheless, the crystallization in the convenient perovskite structure was obtained after annealing treatment under vacuum (5 ×10-3 Pa) at 873 K during 2 hours to prevent the carbonation of the coating. Such crystallized coatings kept mainly their initial morphological properties.

In this study, SrZr0,84Y0,16O3-α (SZY16) coatings and pellets were synthesized by co-sputtering and solid state reaction, respectively, in order to compare their structural and electrical properties. The SZY16 as deposited coatings are amorphous and must be annealed at 623 K to crystallize in the convenient SrZrO3 perovskite structure. After annealing, the grain size of the coatings is about half that of the sintered pellets. SEM analysis shows that both pellets and coatings remain stable after several heating cycles. Activation energies of the total electrical conductivity are 0.68 eV for both the film and the pellet. Nyquist diagrams show that the pellet yields two contributions whereas only one can be detected for the film, attributed to interfacial processes. Finally, the conductivity of the film is about one order of magnitude lower than that of the corresponding bulk pellet.

In this paper, BaZr0,84Y0,16O3-α (BZY16) pellets were synthesized by solid state reaction. ZnO was added at different contents to improve sintering. The effect is investigated as a function of its content in the powder mixture prior to sintering. Whatever the ZnO content, the sole phase observed by X-ray diffraction presents the perovskite structure of BaZrO3 and no trace of crystallized ZnO can be detected. Scanning electron microscopy observations show that the pellets density increases with the ZnO content to reach a maximum around 2 wt.% ZnO. Over this value, a significant increase of macroporosities occurs. On the another hand, the best ionic conductivity is obtained for 1 wt.% ZnO.

International audience; Cu-Cr-O thin films were co-sputtered from metallic Cu and Cr targets in the presence of a reactive argon-oxygen gas mixture. Evolution of the coatings composition as a function of the discharge current dissipated on each target allowed to obtain convenient composition. The films deposited at ambient temperature (without intentional heating of substrate) were initially amorphous and need to be annealed at different temperature under vacuum to achieve delafossite structure. In this case, the delafossite structure presented a thermal instability to the annealing temperature. CuCr2O4 and CuO as the secondary phases were clearly detected by XRD analysis, and could evidently affect the CuCrO2 films optoelectronic properties. Cu-Cr-O thin films were also deposited at high temperatures (substrate temperature varied from 923 to 1083 K) to investigate the influence of substrate temperature on the structure, morphology and optoelectronic properties of the films. Relatively, raising the substrate temperature up to 1033 K was better to obtain CuCrO2 delafossite phase and improved their optoelectronic properties. The optimum conductivity and transparency were achieved for the film deposited at about 1033 K with figure of merit of 6.18 x 10(-13) Omega(-1) (sigma approximate to 1.34 x 10(-2) S cm(-1) and the maximum visible transmittance up to 43%).

International audience; The DC reactive magnetron sputtering of a metallic tungsten target was performed in an argon + oxygen atmosphere for depositing tungsten oxide thin films. In order to control the oxygen concentration in the films, the reactive gas pulsing process, namely RGPP, was implemented. Rectangular pulses were used with a constant pulsing period T = 16 s whereas the duty cycle α (time of oxygen injection to pulsing period T ratio) was systematically changed from 0 to 100% of T. This pulsing injection of the reactive gas allowed a gradual evolution of the films composition from pure metallic to over-stoichiometric WO3+ɛ’ compounds. These WOx films were sputter deposited on commercial MSP 769 Heraeus platforms so as to be used as a sensor for the dodecane gas. It is shown that the sensing performances carried out at 573 K can be adjusted as a function of the duty cycle used during the deposition stage. The relationship between sensing properties and physic-chemical behaviours of the films was especially discussed.

International audience; CuCr0.93Mg0.07O2 thin films with improved optoelectronic properties were deposited by reactive magnetron sputtering on fused quartz substrates. The influence of annealing temperature under vacuum on optoelectronic properties of the films was investigated.The amorphous films annealed under vacuum at temperatures higher than 923K are single-phased delafossite structure, while impurity phases like CuCr2O4 that affect the optoelectronic properties of the films are detected below 873K. c-axis orientation is observed for CuCr0.93Mg0.07O2 layers and the annealing temperature window in which the films are single-phased delafossite is much larger with Mg doping (923K → 1073K) than that for undoped films (~953K). The optical and electrical behaviours of the films are enhanced by Mg substitution and their direct band gap energy of about 3.12–3.14 eV is measured. The film possesses the optimum properties after annealing under vacuum at about 1023K; its average transmittance in the visible region can reach 54.23% while the film’s conductivity is about 0.27 S cm−1.