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1.
CrNx films were deposited on stainless steel and Si (1 1 1) substrates via medium frequency magnetron sputtering in a N2 + Ar mixed atmosphere. The influence of N2 content on the deposition rate, composition, microstructure, mechanical and tribological properties of the as-deposited films was investigated by means of the X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), nanoindentation and tribometer testing. It was found that the N atomic concentration increased and the phase transformed from a mixture of Cr2N + Cr(N) to single-phase Cr2N, and then Cr2N + CrN to pure CrN phase with the increase of N2 content. The Cr 2p3/2 and N 1s of XPS spectra also confirmed the evolution of phase. Accordingly, all films exhibited a typical columnar structure which lies in the zone T of Thornton Model. The mixed Cr2N and Cr(N) phases showed low hardness and high friction coefficient. Cr2N possessed higher hardness than CrN while CrN exhibited lower friction coefficient.  相似文献   

2.
The CrNxOyCz coatings were deposited by planar DC reactive magnetron sputtering onto AZ31 Mg alloy and high speed tool steel (HSTS) substrates at a substrate temperature of 200 °C. The effect of N2 content on composition and structure of the CrNxOyCz coatings was investigated. The structure of the CrNxOyCz coatings was analyzed by a glancing angle X-ray diffraction (GXRD). The cross-section morphology and thickness of the CrNxOyCz coatings were checked by a field emission scanning electron microscope (FESEM), and the composition profile and chemical state were carried out by an X-ray photoelectron spectroscopy (XPS). The experimental results showed that the structure and phase composition of the CrNxOyCz coatings depended on N2 content. The evolution of the structure of CrNxOyCz coatings was consistent with CrNx-based coatings, and the CrNxOyCz coatings contained Cr2O3, CrO2, CrO, Cr3C2, CrNx (Cr, CrN, Cr2N), as well as different chromium oxynitride. However, the carbide and oxynitride were oxidized after annealing.  相似文献   

3.
Two nanocomposite Ti-Cx-Ny thin films, TiC0.95N0.60 and TiC2.35N0.68, as well as one pure TiN, were deposited at 500 °C on Si(1 0 0) substrate by reactive unbalanced dc-magnetron sputtering. Oxidation experiments of these films were carried out in air at fixed temperatures in a regime of 250-600 °C with an interval of 50 °C. As-deposited and oxidized films were characterized and analyzed using X-ray diffraction (XRD), microindentation, Newton's ring methods and atomic force microscopy (AFM). It was found that the starting oxidation temperature of nanocomposite Ti-Cx-Ny thin films was 300 °C irrespective of the carbon content; however their oxidation rate strongly depended on their carbon content. Higher carbon content caused more serious oxidation. After oxidation, the film hardness value remained up to the starting oxidation temperature, followed by fast decrease with increasing heating temperature. The residual compressive stress did not show a similar trend with the hardness. Its value was first increased with increase of heating temperature, and got its maximum at the starting oxidation temperature. A decrease in residual stress was followed when heating temperature was further increased. The film surface roughness value was slightly increased with heating temperature till the starting oxidation temperature, a great decrease in surface roughness was followed with further increase of heating temperature.  相似文献   

4.
Compositionally gradient CrNx coatings were fabricated using arc ion plating by gradually increasing N2 flow rate during the deposition process. The effect of substrate bias, ranging from 0 to −250 V, on film microstructure and mechanical properties were systematically investigated with XRD, SEM, HRTEM, nanoindentation, adhesion and wear tests. The results show that substrate bias has an important influence on film microstructure and mechanical properties of gradient CrNx coatings. The coatings mainly crystallized in the mixture of hexagonal Cr2N, bcc Cr and fcc rock-salt CrN phases. N2 flow rate change during deposition results in phase changes in order of Cr, Cr + Cr2N, Cr2N, Cr2N + CrN, and CrN, respectively, along thickness direction. Phase fraction and preferred orientation in CrNx coatings vary with substrate bias, exerting an effective influence on film hardness. With the increasing of bias, film microstructure evolves from an apparent columnar structure to a highly dense one. The maximum hardness of 39.1 GPa was obtained for the coatings deposited at a bias of −50 V with a friction coefficient of 0.55. It was also found that adhesion property and wear resistance of gradient CrNx coatings were better than that of homogeneous CrN coatings.  相似文献   

5.
The Zn1−xMgxO thin films were grown on Al2O3 substrate with various O2 flow rates by plasma-assisted molecular beam epitaxy (P-MBE). The growth conditions were optimized by the characterizations of morphology, structural and optical properties. The Mg content of the Zn1−xMgxO thin film increases monotonously with decreasing the oxygen flux. X-ray diffractometer (XRD) measurements show that all the thin films are preferred (0 0 2) orientated. By transmittance and absorption measurements, it was found that the band gap of the film decreases gradually with increasing oxygen flow rate. The surface morphology dependent on the oxygen flow rate was also studied by field emission scanning electron microscopy (FE-SEM). The surface roughness became significant with increasing oxygen flow rate, and the nanostructures were formed at the larger flow rate. The relationship between the morphology and the oxygen flow rate of Zn1−xMgxO films was discussed.  相似文献   

6.
Herein is a report of a study on a Cd1−xZnxS thin film grown on an ITO substrate using a chemical bath deposition technique. The as-deposited films were annealed in air at 400 °C for 30 min. The composition, surface morphology and structural properties of the as-deposited and annealed Cd1−xZnxS thin films were studied using EDX, SEM and X-ray diffraction techniques. The annealed films have been observed to possess a crystalline nature with a hexagonal structure. The optical absorption spectra were recorded within the range of 350-800 nm. The band gap of the as-deposited thin films varied from 2.46 to 2.62 eV, whereas in the annealed film these varied from 2.42 to 2.59 eV. The decreased band gap of the films after annealing was due to the improved crystalline nature of the material.  相似文献   

7.
Hydrogenated-carbon nitride (CNx:H) films were synthesized on silicon substrate in a large quantity by the pyrolysis of ethylenediamine in a temperature range of 700-950 °C. The influence of temperature on the morphology, structure, adhesion to substrate, and friction and wear behavior of CNx:H films was investigated. It has been found that CNx:H films obtained at 700 °C and 800 °C are amorphous, and those prepared at 900 °C and 950 °C consist of carbon nitride nanocrystal. Besides, CNx:H film sample obtained at 700 °C has the maximum N content of 9.1 at.% but the poorest adhesion to Si substrate, while the one prepared at 900 °C has the lower N content and the highest adhesion to substrate. As a result, nanocrystalline CNx:H (nc-CNx:H) film synthesized at 900 °C possesses the best wear resistance when slides against stainless steel counterpart. N atom is incorporated into the graphitic network in three different bonding forms, and their relative content is closely related to temperature, corresponding to different adhesion as well as friction and wear behavior of the films obtained at different temperatures. Furthermore, the friction coefficient and antiwear life of as-deposited CNx:H films vary with varying deposition temperature and thickness, and the film with thickness of 1.3 μm, obtained at 900 °C, has the longest antiwear life of over 180,000 s.  相似文献   

8.
Sn1−xMnxO2 (x=0.01-0.05) thin films were synthesized on quartz substrate using an inexpensive ultrasonic spray pyrolysis technique. The influence of doping concentration and substrate temperature on structural and magnetic properties of Sn1−xMnxO2 thin films was systematically investigated. X-ray diffraction (XRD) studies of these films reflect that the Mn3+ ions have substituted Sn4+ ions without changing the tetragonal rutile structure of pure SnO2. A linear increase in c-axis lattice constant has been observed with corresponding increase in Mn concentration. No impurity phase was detected in XRD patterns even after doping 5 at% of Mn. A systematic change in magnetic behavior from ferromagnetic to paramagnetic was observed with increase in substrate temperature from 500 to 700 °C for Sn1−xMnxO2 (x=0.01) films. Magnetic studies reveal room-temperature ferromagnetism (RTFM) with 3.61×10−4 emu saturation magnetization and 92 Oe coercivity in case of Sn1−xMnxO2 (x=0.01) films deposited at 500 °C. However, paramagnetic behavior was observed for the films deposited at a higher substrate temperature of 700 °C. The presence of room-temperature ferromagnetism in these films was observed to have an intrinsic origin and could be obtained by controlling the substrate temperature and Mn doping concentration.  相似文献   

9.
In this paper, TaxC1−x coatings were deposited on 316L stainless steel (316L SS) by radio-frequency (RF) magnetron sputtering at various substrate temperatures (Ts) in order to improve its corrosion resistance and hemocompatibility. XRD results indicated that Ts could significantly change the microstructure of TaxC1−x coatings. When Ts was <150 °C, the TaxC1−x coatings were in amorphous condition, whereas when Ts was ≥150 °C, TaC phase was formed, exhibiting in the form of particulates with the crystallite sizes of about 15-25 nm (Ts = 300 °C). Atomic force microscope (AFM) results showed that with the increase of Ts, the root-mean-square (RMS) values of the TaxC1−x coatings decreased. The nano-indentation experiments indicated that the TaxC1−x coating deposited at 300 °C had a higher hardness and modulus. The scratch test results demonstrated that TaxC1−x coatings deposited above 150 °C exhibited good adhesion performance. Tribology tests results demonstrated that TaxC1−x coatings exhibited excellent wear resistance. The results of potentiodynamic polarization showed that the corrosion resistance of the 316L SS was improved significantly because of the deposited TaxC1−x coatings. The platelet adhesion test results indicated that the TaxC1−x coatings deposited at Ts of 150 °C and 300 °C possessed better hemocompatibility than the coating deposited at Ts of 25 °C. Additionally, the hemocompatibility of the TaxC1−x coating on the 316L SS was found to be influenced by its surface roughness, hydrophilicity and the surface energy.  相似文献   

10.
BixY3−xFe5O12 thin films have been grown on GGG (Gd3Ga5O12) (1 1 1) substrates by the combinatorial composition-spread techniques under substrate temperature (Tsub) ranging from 410 to 700 °C and O2 pressure of 200 mTorr. In order to study the effect of substrates on the deposition of BixY3−xFe5O12 thin films, garnet substrates annealed at 1300 °C for 3 h were also used. Magneto-optical properties were characterized by our home-designed magneto-optical imaging system. From the maps of Faraday rotation angle θF, it was evident that the Faraday effect appears only when Tsub = 430-630 °C. θF reaches to the maximum value (∼6°/μm, λ = 632 nm) at 500 °C, and is proportional to the Bi contents. XRD and EPMA analyses showed that Bi ions are easier to substitute for Y sites and better crystallinity is obtained for annealed substrates than for commercial ones.  相似文献   

11.
Zn1−xCoxO thin films with c-axis preferred orientation were deposited on sapphire (0 0 0 1) by pulsed laser deposition (PLD) technique at different substrate temperatures in an oxygen-deficient ambient. The effect of substrate temperature on the microstructure, morphology and the optical properties of the Zn1−xCoxO thin films was studied by means of X-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible-NIR spectrophotometer, fluorescence spectrophotometer. The results showed that the crystallization of the films was promoted as substrate temperature rose. The structure of the samples was not distorted by the Co incorporating into ZnO lattice. The surface roughness of all samples decreased as substrate temperature increased. The Co concentration in the film was higher than in the target. Emission peak near band edge emission of ZnO from the PL spectra of the all samples was quenched because the dopant complexes acted as non-radiative centers. While three emission bands located at 409 nm (3.03 eV), 496 nm (2.5 eV) and 513 nm (2.4 eV) were, respectively, observed from the PL spectra of the four samples. The three emission bands were in relation to Zn interstitials, Zn vacancies and the complex of VO and Zni (VOZni). The quantity of the Zn interstitials maintained invariable basically, while the quantity of the VOZni slightly decreased as substrate temperature increased.  相似文献   

12.
We have fabricated high-quality FeSe1−x superconducting films with a bulk Tc of 11–12 K on different substrates, Al2O3(0 0 0 1), SrTiO3(1 0 0), MgO(1 0 0), and LaAlO3(1 0 0), by using a pulsed laser deposition technique. All the films were grown at a high substrate temperature of 610 °C, and were preferentially oriented along the (1 0 1) direction, the latter being to be a key to fabricating of FeSe1−x superconducting thin films with high Tc. According to the energy dispersive spectroscopy data, the Fe:Se composition ratio was 1:0.90 ± 0.02. The FeSe1−x film grown on a SrTiO3 substrate showed the best quality with a high upper critical magnetic field [Hc2(0)] of 56 T.  相似文献   

13.
SiCxNy thin films with different nitrogen contents were deposited by way of incorporation of different amounts of nitrogen into SiC0.70 using unbalanced reactive dc magnetron sputtering method. Their phase configurations, nanostructures and mechanical behaviors were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and microindentation methods. The result indicated SiC0.70 and all SiCxNy thin films exhibited amorphous irrespective of the nitrogen content. The phase configuration and mechanical behaviors of SiCxNy thin films strongly depended on nitrogen content. SiC0.70 exhibited a mixture consisting of SiC, Si and a small amount of C. Incorporated nitrogen, on one hand linked to Si, forming SiNx, on the other hand produced CNx and C at the expense of SiC. As a result, an amorphous mixture consisting of SiC, SiNx, C and CNx were produced. Such effects were enhanced with increase of nitrogen content. A low hardness of about 16.5 GPa was obtained at nitrogen-free SiC0.70. Incorporation of nitrogen or increase of nitrogen content increased the film hardness. A microhardness maximum of ∼29 GPa was obtained at a nitrogen content of 15.7 at.%. This value was decreased with further increase of N content, and finally a hardness value of ∼22 GPa was obtained at a N content of ∼25 at.%. The residual compressive stress was consistent with the hardness in the nitrogen content range of 8.6-25.3 at.%.  相似文献   

14.
Rare-earth oxide films for gate dielectric on n-GaAs have been investigated. The oxide films were e-beam evaporated on S-passivated GaAs, considering interfacial chemical bonding state and energy band structure. Rare-earth oxides such as Gd2O3, (GdxLa1−x)2O3, and Gd-silicate were employed due to high resistivity and no chemical reaction with GaAs. Structural and bonding properties were characterized by X-ray photoemission, absorption, and diffraction. The electrical characteristics of metal-oxide-semiconductor (MOS) diodes were correlated with material properties and energy band structures to guarantee the feasibility for MOS field effect transistor (FET) application.Gd2O3 films were grown epitaxially on S-passivated GaAs (0 0 1) at 400 °C. The passivation induced a lowering of crystallization temperature with an epitaxial relationship of Gd2O3 (4 4 0) and GaAs (0 0 1). A better lattice matching relation between Gd2O3 and GaAs substrate was accomplished by the substitution of Gd with La, which has larger ionic radius. The in-plane relationship of (GdxLa1−x)2O3 (4 4 0) with GaAs (0 0 1) was found and the epitaxial films showed an improved crystalline quality. Amorphous Gd-silicate film was synthesized by the incorporation of SiO2 into Gd2O3. These amorphous Gd-silicate films excluded defect traps or current flow path due to grain boundaries and showed a relatively larger energy band gap dependent on the contents of SiO2. Energy band parameters such as ΔEC, ΔEV, and Eg were effectively controlled by the film composition.  相似文献   

15.
NbNx films were deposited on Nb substrate using pulsed laser deposition. The effects of substrate deposition temperature, from room temperature to 950 °C, on the preferred orientation, phase, and surface properties of NbNx films were studied by X-ray diffraction, atomic force microscopy, and electron probe micro analyzer. We find that the substrate temperature is a critical factor in determining the phase of the NbNx films. For a substrate temperature up to 450 °C the film showed poor crystalline quality. With temperature increase the film became textured and for a substrate temperature of 650−850 °C, mix of cubic δ-NbN and hexagonal phases (β-Nb2N + δ′-NbN) were formed. Films with a mainly β-Nb2N hexagonal phase were obtained at deposition temperature above 850 °C. The c/a ratio of β-Nb2N hexagonal shows an increase with increased nitrogen content. The surface roughness of the NbNx films increased as the temperature was raised from 450 to 850 °C.  相似文献   

16.
A series of ZnO1−xSx alloy films (0 ≤ x ≤ 1) were grown on quartz substrates by radio-frequency (rf) magnetron sputtering of ZnS ceramic target, using oxygen and argon as working gas. X-ray diffraction measurement shows that the ZnO1−xSx films have wurtzite structure with (0 0 2) preferential orientation in O-rich side (0 ≤ x ≤ 0.23) and zinc blende structure with (1 1 1) preferential orientation in S-rich side (0.77 ≤ x ≤ 1). However, when the S content is in the range of 0.23 < x < 0.77, the ZnO1−xSx film consists of two phases of wurtzite and zinc blende or amorphous ZnO1−xSx phase. The band gap energy of the films shows non-linear dependence on the S content, with an optical bowing parameter of about 2.9 eV. The photoluminescence (PL) measurement reveals that the PL spectrum of the wurtzite ZnO1−xSx is dominated by visible band and its PL intensity and intensity ratio of UV to visible band decrease greatly compared with undoped ZnO. All as-grown ZnO1−xSx films behave insulating, but show n-type conductivity for w-ZnO1−xSx and maintain insulating properties for β-ZnO1−xSx after annealed. Mechanisms of effects of S on optical and electrical properties of the ZnO1−xSx alloy are discussed in the present work.  相似文献   

17.
The (γ′-Fe4N/Si-N)n (n: number of layers) multilayer films and γ′-Fe4N single layer film synthesized on Si (1 0 0) substrates by direct current magnetron sputtering were annealed at different temperatures. The structures and magnetic properties of as-deposited films and films annealed at different temperatures were characterized using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. The results showed that the insertion of Si-N layer had a significant influence on the structures and magnetic properties of γ′-Fe4N film. Without the addition of Si-N lamination, the iron nitride γ′-Fe4N tended to transform to α-Fe when annealed at the temperatures over 300 °C. However, the phase transition from γ′-Fe4N to ?-Fe3N occurred at annealing temperature of 300 °C for the multilayer films. Furthermore, with increasing annealing temperature up to 400 °C or above, ?-Fe3N transformed back into γ′-Fe4N. The magnetic investigations indicated that coercivity of magnetic phase γ′-Fe4N for as-deposited films decreased from 152 Oe (for single layer) to 57.23 Oe with increasing n up to 30. For the annealed multilayer films, the coercivity values decreased with increasing annealing temperature, except that the film annealed at 300 °C due to the appearance of phase ?-Fe3N.  相似文献   

18.
We have deposited germanium carbide (Ge1−xCx) films on Si(1 0 0) substrate via radio-frequency (RF) reactive magnetron sputtering in a CH4/Ar mixture discharge, and explored the effects of carbon content (x) on the chemical bonding and hardness for the obtained films. We find that x significantly influences the chemical bonding, which leads to a pronounced change in the hardness of the film. To reveal the relationship between the chemical bonding and hardness, first-principles calculations have been carried out. It is shown that as x increases from 0 to 0.33, the fraction of sp3 C-Ge bonds in the film increases at the expense of Ge-Ge bonds, which promotes formation of a strong covalently bonded network, and thus enhances the hardness of the film. However, as x further increases from 0.33 to 0.59, the fraction of sp3 C-Ge bonds in the film gradually reduces, while that of sp3 C-H and graphite-like sp2 C-C bonds increases, which damages the compact network structure, resulting in a sharp decrease in the hardness. This investigation suggests that the medium x (0.17<x<0.40) is most favorable to the preparation of hard Ge1−xCx films due to the formation of dominant sp3 C-Ge bonds.  相似文献   

19.
This investigation experimentally studies the low-frequency alternating-current magnetic susceptibility (χac) of amorphous and nanocrystalline CoFeB films by measuring the magnetic field established by passing currents of various frequencies through such films of various thicknesses (tf). A CoFeB film is sputtered onto a glass substrate with tf from 100 Å to 500 Å under the following conditions: (a) As-deposited films were maintained at room temperature (RT) and (b) films were post-annealed at TA=150 °C for 1 h. The samples thus obtained are analyzed in a magnetic field that was generated by an alternating current (AC) at various frequencies from 10 Hz to 25,000 Hz. The experimental results demonstrate that the χac declines as the thickness of the as-deposited sample and the post-annealed sample (TA=150 °C) increases because the lower coercivity (Hc) of thinner CoFeB films is similar to a soft magnetic characteristic and is associated with a higher χac value. The best χac value is obtained at a thickness of 100 Å under both conditions. The χac value of the post-annealed sample exceeds that of the RT sample at thicknesses from 100 Å to 500 Å because the magneto crystalline anisotropy of the post-annealed sample yields the highest χac value at the optimal resonance frequency (fres), at which the spin sensitivity is maximal. The X-ray diffraction patterns (XRD) of as-deposited CoFeB films reveal their amorphous structure. The XRD results for the post-annealed films include a main peak at 2θ=44.7° from the body-centered cubic (BCC) nanocrystalline CoFe that indicated a (110) textured structure. Post-annealing treatment caused that the amorphous structure to become more crystalline by a thermally driven process, such that the χac value of the post-annealed sample exceeded that of the RT sample. This experimental result demonstrates that the χac value decreased as the thickness of the thin film increased. Finally, the CoFeB thin films had the best χac at low frequency (<50 Hz) following post-annealing treatment. The results obtained under the two conditions indicate that the maximum χac value and the optimal fres of a 100 Å-thick CoFeB thin film were 1.6 and 30 Hz, respectively, following post-annealing at TA=150 °C for 1 h, suggesting that a 100 Å-thick CoFeB thin film that has been post-annealed at TA=150 °C can be utilized as a gage sensor and in transformer applications at low frequencies.  相似文献   

20.
Be3N2 thin films have been grown on Si(1 1 1) substrates using the pulsed laser deposition method at different substrate temperatures: room temperature (RT), 200 °C, 400 °C, 600 °C and 700 °C. Additionally, two samples were deposited at RT and were annealed after deposition in situ at 600 °C and 700 °C. In order to obtain the stoichiometry of the samples, they have been characterized in situ by X-ray photoelectron (XPS) and reflection electron energy loss spectroscopy (REELS). The influence of the substrate temperature on the morphological and structural properties of the films was investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD). The results show that all prepared films presented the Be3N2 stoichiometry. Formation of whiskers with diameters of 100-200 nm appears at the surface of the films prepared with a substrate temperature of 600 °C or 700 °C. However, the samples grown at RT and annealed at 600 °C or 700 °C do not show whiskers on the surface. The average root mean square (RMS) roughness and the average grain size of the samples grown with respect the substrate temperature is presented. The films grown with a substrate temperature between the room temperature to 400 °C, and the sample annealed in situ at 600 °C were amorphous; while the αBe3N2 phase was presented on the samples with a substrate temperature of 600 °C, 700 °C and that deposited with the substrate at RT and annealed in situ at 700 °C.  相似文献   

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