Wear behavior of HPPMS deposited (Ti,Al,Si)N coating under impact loading

Over the last decade the interest in High Power Pulse Magnetron Sputtering (HPPMS) and High impulse Magnetron Sputtering (HiPIMS) has undergone a considerable increase. This is mainly due to the fact that several researchers have shown that in these processes a distinct increase of the ionization of deposition species is observable. However, there is only little known about the performance of these films with regard to applications. Recently Hovsepian et al. [1] and Bobzin et al. [2] presented cutting results of different films. Both authors show that films deposited using HPPMS or HiPIMS outperform state‐of‐the‐art coatings. Depending on the cutting process, besides hardness and adhesion also excellent impact behavior is required. Therefore this work deals with the impact behavior of (Ti,Al,Si)N which was deposited using HPPMS for the application in interrupted cutting process. The impact behavior of HPPMS coating under normal and tangential loads is analyzed. During impact tests number of impacts, loads and inclination angle of the samples with regard to the load direction are varied. (Ti,Al,Si)N shows an excellent endurance even at very high loads causing Hertzian stresses in the range of 10–13 GPa. At an inclination angle of 10° and an impact load of 100 N, which corresponds to app. 10 GPa initial Hertzian stress, no damage was observed after 800×10³ impacts.     

Ultrafast thermal plasma physical vapor deposition of thick SiC films

Thick silicon carbide films have been successfully deposited at a deposition rate of 125 nm/s on stationary graphite substrates by the thermal plasma physical vapor deposition technique, with ultrafine SiC powder fed into a hybrid plasma jet and completely evaporated. The relationship between the processing parameters and the morphology, deposition rate, composition and crystal structure has been investigated under the typical conditions of substrate temperature in the range of 1400–1700 °C and chamber pressure of 250 Torr, and compared with the results of rotating substrate deposition at the substrate temperature of around 750 °C. It was found that the deposition rate and composition showed different processing parameter dependences for rotating substrate deposition and stationary substrate deposition. The films showed dense cross-sections or cauliflower-like structures depending on the deposition conditions.

©2003 Elsevier Science Ltd. All rights reserved.     

Structural and chemical characteristics of (Ti,Al)N films prepared by ion mixing and vapor deposition

The characterization of titanium aluminum nitride (Ti,Al)N films prepared by ion mixing and vapor deposition (IVD) technique has been performed using several analytical techniques. In this study, the phase diagram of the films with various evaporation ratios Al/Ti was summarized successfully. The phase transition from single-phase NaCl to double-phase (NaCl+wurtzite) structure occurs with an increase of Al/Ti and/or with a decrease of substrate temperature. The (Ti,Al)N films with two-phase structure have a high performance in hardness. They are also highly resistant to oxidation. Consequently, the results suggest that the Al oxide layers formed on the top of (Ti,Al)N films during elevated temperature oxidation tests protect the films from further oxidation.     

Deposition of nanocrystalline translucent h-BN films by chemical vapor deposition at high temperature

h-BN layers were deposited on α-SiC and sapphire substrates by chemical vapor deposition at high temperature (1500-1900 °C) using B₂H₆ and NH₃ diluted in Ar. Growth rates were in the 6-10 μm/h range. In all the conditions studied, the as deposited BN layers were found to be translucent to light, some having a light whitish aspect and other a more yellowish one. It was also observed that the deposit was not always adhesive. Characterizations showed that the layers were nano-crystalline with crystallite size < 10 nm. The growth rate was found to be temperature and N/B ratio dependent due to an N limited growth regime which is more pronounced above 1700 °C.     

Catalyst-free synthesis of macro-scale ZnO nanonail arrays on Si substrate by simple physical vapor deposition

Macro-scale ZnO nanonail arrays have been synthesized on silicon wafer by a simple physical vapor deposition approach without any catalyst. These synthesized ZnO nanonails grow vertically on the substrate with their caps upside. This probably results from the crowding effect. Each ZnO nanonail has a large hexagonal cap and a thinner shaft of several microns in length. Most of the nanonails are perfect single crystals with wurtzite structure and their preferred growth orientation is along [001] direction. The growth mechanism is VS mechanism and the detailed growth process is also proposed. The macro-scale nanonail arrays on Si substrate could offer novel opportunities for both fundamental research and technological applications.     

Experimental development and deposition of nanocomposite films by a hybrid dc magnetron sputtering and cluster gun technique

A novel hybrid experimental prototype involving dc magnetron sputtering combined with an ingenious nanocluster source has been developed to deposit nanocomposite coatings by incorporating pre-formed clusters into a sputtered coating under high vacuum conditions. An electromagnetic fuel injector was connected with the nanocluster chamber and then optimised along with the sputtering chamber in order to incorporate the clusters in the coating matrix. The injection flux was primarily controlled by: the argon pressure and the amount of nanoclusters, the duration and repetition time of the injection and distance between the nozzle of the injector and the substrates. Several experiments were carried out on various substrates such as carbon tape, Al, Si and M2 steel with different nanoparticles of WO₃, SiC and WS₂. The preliminary characterization, consisting in the phase analysis, SEM micrographs and elemental composition, allowed confirming the presence of the clusters attached to the carbon tape when a free plasma injection was performed. Furthermore, the co-existence of Ti and TiN matrixes containing the SiC, WO₃ and WS₂ nanoparticles was confirmed.     

Thermoelectric properties of SiC thick films deposited by thermal plasma physical vapor deposition

SiC thick films of about 300 µm could be prepared with a deposition rate above 300 nm/s by thermal plasma physical vapor deposition (TPPVD) using ultrafine SiC powder as a starting material. The thermoelectric properties were investigated as a function of composition and doping content. The nondoped films showed n-type conduction. Although the Seebeck coefficient reached as high as -480 µV/K, the power factor was only around 1.6 × 10^-4 Wm^-1 K^-2 at 973 K due to the relatively high electrical resistivity. In order to reduce the electrical resistivity and to deposit layers with n-type and p-type conduction, N₂, B and B₄C were selected as the dopants. Nitrogen-doped samples exhibit n-type characterization, B and B₄C-doped samples exhibit p-type characterization, and the electrical resistivity decreased from 10^-2–10^-3 to 10^-4–10^-5 Ωm after doping. The maximum power factor of the nitrogen-doped SiC and the thick films deposited with B₄C powder reached 1.0 × 10^-3 and 6.4 × 10^-4 Wm^-1 K^-2 at 973 K, respectively.

© 2003 Elsevier Science Ltd. All rights reserved.     

Ge组分渐变的Si1-x-yGexCy薄膜的制备

用化学气相淀积方法在Si（100）衬底上外延生长了Ge组分最高约0．40的组分渐变的Si1-x-yGexCy合金薄膜,研究了生长温度等工艺参数的影响．结果表明,生长温度和C2H4分压的提高均导致薄膜中碳组分的增加和合金薄膜晶格常数的减小,这表明外延薄膜中的C主要以替位式存在．C掺入量的变化可有效地调节薄膜的禁带宽度,而提高生长温度有助于改善Si1-x-yGexCy薄膜的的晶体质量．组分渐变的Si1-x-yGexCy合金薄膜包括由因衬底中Si原子扩散至表面与GeH4．C2H4反应而生成的Ni1-x-yGexCy外延层和由Ni1-x-yGexCy外延层中Ge原子向衬底方向扩散而形成的Ni1-xGex层．     

Micro-hardness, microstructures and thermal stability of (Ti,Cr,Al,Si)N films deposited by cathodic arc method

(Ti,Cr,Al,Si)N films were deposited by cathodic arc method using TiCrAlSi alloy cathodes. It was found that the microstructures of (Ti,Cr,Al,Si)N were closely related to (Al+Si) content. The crystal structure of (Ti,Cr,Al,Si)N was NaCl-type structure up to the (Al+Si) content of 0.60, where it changed to a hexagonal structure. The maximum hardness of 33 GPa was obtained at the lowest (Al+Si) content of 0.56, still in the cubic structure. The micro-hardness decreased down to 28 GPa as the crystal structure changed from NaCl-type to wurtzite-type.To investigate the thermal stabilities of (Ti,Cr,Al,Si)N, the films were annealed in a vacuum furnace. In Ti_0.20Cr_0.20Al_0.55Si_0.05N with cubic structure, the phase segregation occurred by annealing at over 900 °C, while Ti_0.22Cr_0.22Al_0.44Si_0.12N remained in cubic phase up to 1000 °C. The micro-hardness of Ti_0.20Cr_0.20Al_0.55Si_0.05N increased and that of Ti_0.22Cr_0.22Al_0.44Si_0.12N decreased at 1000 °C. Ti_0.20Cr_0.11Al_0.58Si_0.11N with a cubic and hexagonal mixture phase held its (c,h)-mixture phase up to 1000 °C, while there was an indication of an increase both in micro-hardness and in cubic ratio after annealing.In this paper, the micro-hardness and microstructure of (Ti,Cr,Al,Si)N are discussed as a function of annealing temperature and investigated by X-ray diffraction and electron microscopy.     

Fatigue strength of an (α + β)-type titanium alloy Ti-6Al-4V produced by the electron-beam physical vapor deposition method

The fatigue test results are presented for an (α + β )-type titanium alloy Ti-6Al-4V in the form of two-layered smooth specimens (the first layer is a condensate prepared by the electron-beam physical vapor deposition method, the second one is a substrate from a standard sheet material of the same type) and condensate specimens. It has been found that the presence in the condensate of deposition defects such as droplets lowers the fatigue limit of the material by approximately 1.5 times as compared to that of the condensate which is free of defects. It is shown that in the absence of droplets, the fatigue limit of the condensate is no lower than that of the substrate material. The microstructure, texture and fracture surfaces of the materials under study are analyzed, on the basis of which the fatigue limits of the defectless condensate and substrate material are calculated using approaches of linear fracture mechanics. Good agreement has been obtained between calculated and experimental data. __________ Translated from Problemy Prochnosti, No. 6, pp. 113–121, November–December, 2006.     

Epitaxial growth of titanium oxide thin films on MgO(100) single-crystal substrates by reactive deposition methods

We synthesized titanium oxide thin films on MgO(100) single-crystal substrates by two reactive deposition methods and compared the structures of the thin films formed by these methods. In one method (pulsed-molecular-beam deposition method), molecular oxygen is supplied to the substrates by using a pulsed-molecular-oxygen beam source and deposition of one unit layer of titanium and subsequent supply of molecular oxygen are repeatedly performed. In the other method (radical beam deposition method), atomic oxygen is irradiated to the substrates by using an atomic oxygen beam generated by the radical beam source and irradiation of the atomic oxygen and deposition of titanium are simultaneously performed. In the case of the pulsed-molecular-beam deposition method, the crystal structure was changed by increasing the number of oxygen pulses supplied from the beam source. We found that the crystal structure of titanium oxide depended on the composition ratio of O:Ti in the film. The maximum ratio of O:Ti attainable by this method was 1.85, and at this ratio, (100)-oriented pseudorutile was formed. In the case of the radical beam deposition method, (100)-oriented anatase was formed below the titanium deposition rate of 0.10 nm/s and pseudorutile (TiO_2−δ) was formed above 0.15 nm/s. The pseudorutile structure synthesized on this experiment was very stable in air. We concluded that the crystal structure of the pseudorutile is a new crystal structure of titanium oxide.     

Field-induced strain of (Pb, La)(Zr, Ti)O3 epitaxial films grown by metal organic chemical vapor deposition

Two micrometers thick (Pb, La)(Zr, Ti)O₃ [PLZT] films with wide composition range were epitaxially grown on (1 0 0)SrRuO₃ bottom electrode layers epitaxially grown (1 0 0) SrTiO₃ substrates by metal organic chemical vapor deposition. Constituent phase of the films were found to be almost the same with the reported phase diagram for the sintered body except for the wider coexistence region of tetragonal and rhombohedral phases. The change of the measured field-induced strain with the electric field was almost respond to the square of the polarization of the films except the negative strain region, but the magnitude was different. This is due to the increase of the electrostatic coefficient of the film with increasing the La/(Pb + La) ratio. As a results, field induced strain of the PLZT film was found to be controlled by adjusting the composition of PLZT films.     

Initiated chemical vapor deposition of pH responsive poly(2-diisopropylamino)ethyl methacrylate thin films

Poly(2-(diisopropylamino)ethyl methacrylate) (PDPAEMA) thin films were deposited on low temperature substrates by initiated chemical vapor deposition (iCVD) method using tertbutyl peroxide as an initiator. Very high deposition rates up to 38 nm/min were observed at low filament temperatures due to the use of the initiator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy show the formation of PDPAEMA films with high retention of tertiary amine functionality which is responsible for pH induced changes in the wetting behavior of the surfaces. As-deposited PDPAEMA thin films on flat Si surface showed a reversible switching of water contact angle values between 87° and 28°; after successive treatments of high and low pH water solutions, respectively. Conformal and non-damaging nature of iCVD allowed to functionalize fragile and rough electrospun poly(methyl methacrylate) fiber mat surfaces by PDPAEMA, which creates a surface with a switching behavior between superhydrophobic and approaching superhydrophilic with contact angle values of 155 ± 3°and 22 ± 5°, respectively.     

Effect of the microstructure on the cutting performance of superhard (Ti,Si,Al)N nanocomposite films

A d.c. reactive magnetron sputtering technique was used to deposit (Ti,Si,Al)N coatings onto WC-Co cutting tools. The microstructure of the coatings was analysed using X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) measurement. Before the cutting experiments, the XRD results revealed a structure indexed to an fcc TiN. The results obtained by the XRD tests, with detector variation in asymmetric mode (rocking curves) showed a decrease in the quality of the fiber texture in the (111) grains with the change on deposition chamber geometry (two magnetrons in place of four magnetrons). Cross-sectional HRTEM images of the (Ti,Al)N sample showed grains with a diameter between 16 and 30 nm, while for the (Ti,Si,Al)N samples grains with a diameter between 6 and 10 nm were observed. Furthermore, through the visualization of bright field images it was possible to discern a columnar structure. For samples prepared at high deposition rates (2 μm/h), HRTEM micrographs revealed the formation of the multilayer stacking of (Ti,Si)N/(Ti,Al)N.     

Investigation of the aluminum oxide/Si(1 0 0) interface formed by chemical vapor deposition

Thin films of aluminum oxide were deposited using trimethylaluminum and oxygen. The deposition rate was found to decrease with increasing temperature. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to investigate the film/substrate interface. When dry O₂ was used during deposition, the film/substrate interface was free of any silicon dioxide or aluminum silicate phase. On annealing the as-deposited films in Ar, a layer of silicon dioxide film formed at the interface. XPS results indicated that the O/Al ratio in the as-deposited films was higher than that in stoichiometric Al₂O₃. However, the ratio was found to decrease in the annealed samples suggesting that excess oxygen present in the deposited films is responsible for the formation of interfacial silicon dioxide layer. Interfacial phase formation was observed in the as-deposited samples, when small amounts of ozone along with oxygen were used as the oxygen precursor.     

Filter effects on the wear and corrosion behaviors of arc deposited (Ti,Al)N coatings for application on cold-work tool steel

In this study, (Ti,Al)N coatings were deposited on Japanese Industrial Standard SKD11 modified cold-work tool steel using a cathodic arc deposition system with and without magnetic filter attachment. Coating morphology and properties such as coating structure, adhesion, hardness, abrasion and corrosion behaviors were analyzed to evaluate the effects of magnetic filter on the coatings. The results showed that magnetic filtering slowed down (Ti,Al)N deposition rate, but it improved component homogeneity, roughness and adhesion of the coatings. Although (Ti,Al)N coated specimens produced with or without filter both showed superior abrasion resistance in service, however, filtered (Ti,Al)N coatings yielded better corrosion protection of the steel than unfiltered ones in 3.5 wt.% NaCl aqueous medium.     

等离子喷涂-物理气相沉积Si/莫来石/Yb2SiO5环境障涂层

采用等离子喷涂-物理气相沉积技术(PS-PVD)在SiC/SiC复合材料表面依次制备了Si(底层)、3Al₂O₃-2SiO₂ (中间层)、Yb₂SiO₅(面层)环境障涂层(EBC)。利用扫描电子显微镜(SEM)观察分析EBC涂层表面与界面的微观形貌, X射线衍射仪对喷涂过程中易非晶化的莫来石涂层进行物相分析, 研究了喷涂粉末与高温等离子体的相互作用并探讨了EBC涂层的沉积机制。结果表明：通过PS-PVD技术可制备出低孔隙率、高致密界面的EBC涂层。通过观察EBC涂层表面, Si涂层表面无裂纹, 而莫来石和Yb₂SiO₅涂层表面均发现有微裂纹, 其中莫来石涂层表面的裂纹尺度大于Yb₂SiO₅涂层。三层结构的致密EBC涂层以液相沉积为主, 同时伴随有气、固沉积。在Yb₂SiO₅涂层沉积过程中, 液相沉积导致涂层为致密的层状结构, 蒸发后气相在等离子焰流中及基体表面发生均匀形核和非均匀形核导致涂层中出现大量的纳米晶粒, 而微熔粒子和溅射粒子则形成涂层中亚微米、微米晶粒。     

Preparation of CuInSe2 thin films through metal organic chemical vapor deposition method by using di-μ-methylselenobis(dimethylindium) and bis(ethylisobutyrylacetato) copper(II) precursors

Highly polycrystalline copper indium diselenide (CuInSe₂) thin films on molybdenum substrate were successfully grown at 330 °C through two-stage metal organic chemical vapor deposition (MOCVD) method by using two precursors at relatively mild conditions. First, phase pure InSe thin film was prepared on molybdenum substrate by using a single-source precursor, di-μ-methylselenobis(dimethylindium). Second, on this InSe/Mo film, bis(ethylisobutyrylacetato) copper(II) designated as Cu(eiac)₂ was treated by MOCVD to produce CuInSe₂ films. The thickness and stoichiometry of the product films were found to be easily controlled in this method by adjusting the process conditions. Also, there were no appreciable amounts of carbon and oxygen impurities in the prepared copper indium diselenide films.     

On the photoluminescence of multilayer arrays of silicon rich oxide with high silicon content prepared by low pressure chemical vapor deposition

The photoluminescence emission of multilayer structures composed of layers of silicon rich oxide with high silicon content and layers of silicon rich oxide with low silicon content obtained by low pressure chemical vapor deposition is here presented. Different parameters for the preparation of the multilayers have been varied such as the Si concentration and the thicknesses of the layers. Additionally, the samples were oxidized at different temperatures. For all samples the photoluminescence seems to have the same origin: defects in the oxide matrix and defects at the interfaces between the Si nanocrystals. The structural and compositional properties of the multilayer structures are discussed.