Search results for "physical vapor deposition"

The Effect of surface topographical changes of two different surface treatments rotary instrument

2018

Background One of the major innovations in endodontics has been the introduction of nickel-titanium (NiTi) alloy. This study evaluated the surface topographical changes of two different surface treatments rotary instrument after instrumentation and sterilization. Material and Methods 240 Extracted teeth were included in this study. 90 new AlphaKite and Revo-S NiTi rotary instruments were selected and divided into two groups (Group A 45 AlphaKite and group B 45 Revo-S). Each group were divided into three subgroups: (A1, B1) n=5 files were used as a control, (A2,B2) n=20 files were used to prepare three root canals using endodontic rotary motor then sterilized by autoclave for one cycle under…

Study of the Chemical Conversion of Aluminum Alloys by Coupling CFDE and EQCM

2004

The ability of the channel flow double electrode (CFDE) technique and electrochemical quartz crystal microbalance (EQCM) for studying in situ chromate phosphate conversion coating on 5182 aluminum alloys was explored. It was first demonstrated that aqueous Cr(VI) can be analyzed quantitatively with the CFDE technique by reduction into Cr(III) on a graphite electrode. Samples used for EQCM were quartz plated by physical vapor deposition using a 5182 alloy target, allowing thin layers of aluminum alloys with a similar chemical composition to be obtained. EQCM was adapted in order to account for the hydrodynamic conditions in an industrial process, by placing the quartz in a flow cell. In orde…

Microhardness and adhesion measurements of reactively sputtered TiN/AlN multilayer coatings deposited as function of mass-flow of nitrogen

1998

Abstract Multilayer coatings of (Ti, Al)N x have been deposited by reactive sputtering from Ti and Al targets in a side-by-side configuration on WC and stainless steel substrates. The rotation of the substrate holder varied from 2 to 14 r.p.m. corresponding to a bilayer thickness of 0.8–8 nm. The acoustic emission scratch technique for adhesion measurements was used for studying coating performance, and critical load values for the coatings on WC substrate up to 150 N were obtained. The Vickers microhardness in the load range 0.003–2 N was measured, and in order to obtain true hardness values, an optimal range of indentation depth and coating thickness was determined. Depending on the nitro…

Growth mechanisms and related thermoelectric properties of innovative hybrid networks fabricated by direct deposition of Bi2Se3 and Sb2Te3 on multiwa…

2020

Abstract Flexible thermoelectric generators are an emerging trend in the field of waste heat conversion, as well as wearable and autonomous devices. However, the energy conversion efficiency of the state-of-the-art flexible thermoelectric devices is too low for their wide application and commercialization. In this work, n- and p-type multiwalled carbon nanotube (MWCNT)-thermoelectric material hybrid networks that may become a promising building block for the fabrication of flexible thermoelectric devices are presented. The hybrid networks were fabricated by direct deposition of thermoelectric material (Bi2Se3, Sb2Te3) on the MWCNT networks using physical vapor deposition technique. Growth m…

Physical vapor deposition of Bi2S3 as absorber material in thin film photovoltaics

2013

Abstract In order to investigate alternative absorber materials for inorganic solar cells, thin films of bismuth trisulfide (Bi2S3) were deposited under high vacuum conditions by the thermal evaporation method from compound material. The effects of the substrate temperature during deposition on the structural, stoichiometric, optical and electrical properties were investigated. Polycrystalline thin films close to an ideal stoichiometry could be deposited for temperatures TSub = 80–290 °C; thereby a transition from rough needle-shaped particles with (hk0)-orientation parallel to the surface of the substrate towards block shaped grains with a preferred direction out of the surface could be ob…

MoO (x≤2) ultrathin film growth from reactions between metallic molybdenum and TiO2 surfaces

2001

Abstract Exposures to oxygen at room temperature and annealings under vacuum were carried out on deposits obtained from molybdenum interacting with (1 1 0) TiO 2 surfaces in order to obtain molybdenum oxide ultra thin films. Exposures to oxygen at room temperature show that the interfacial molybdenum oxide layers resulting from the TiO 2 /Mo interactions are inactive towards oxygen whereas the metallic molybdenum clusters, which grew on top of the interfacial layers, oxidise into MoO 3 . Besides, during annealings under vacuum, substrate oxygen anions can diffuse into the deposit. Thus, between 400 and 500°C, molybdenum oxide layers are progressively oxidised into MoO 2 . Moreover, from the…

2018

Damping distances of surface plasmon polariton modes sustained by different thin titanium nitride (TiN) films are measured at the telecom wavelength of 1.55 μm. The damping distances are correlated to the electrical direct current resistivity of the films sustaining the surface plasmon modes. It is found that TiN/Air surface plasmon mode damping distances drop non-linearly from 40 to 16μm as the resistivity of the layers increases from 28 to 130μΩ.cm, respectively. The relevance of the direct current (dc) electrical resistivity for the characterization of TiN plasmonic properties is investigated in the framework of the Drude model, on the basis of parameters extracted from spectroscopic ell…

Investigations of TiO2 films deposited by different techniques

1991

High refractive TiO2 films deposited by reactive electron beam evaporation, reactive ion plating and dip coating have been characterized by optical spectroscopy, electron spectroscopy for chemical analysis, Rutherford backscattering spectroscopy, nuclear reaction analysis and Raman spectroscopy. The spectral refractive index n exhibits a strong dependence on the deposition conditions. These findings will be connected to variations in density, stoichiometry, hydrogen content (H2O) and binding structure of the layers. A strong correlation is found between optical quantities and microscopic properties of TiO2 films.

Preparation of Catalysts and Photocatalysts Used for Similar Processes

2019

Abstract This chapter reports the main techniques used to synthesize powders and films of heterogeneous catalysts and photocatalysts, often used for similar processes. Traditional preparation processes of bulky (photo)catalysts including precipitation, sol–gel technique, hydrothermal or solvothermal method, solid-state reactions, and flame syntheses were briefly described. The sonochemical method and microwave irradiation technique were also considered. The syntheses of supported catalysts by different techniques, including deposition–precipitation, impregnation, and wet coating technologies were also described. Moreover, a survey is reported of methods to deposit thin films of catalysts on…

Sputtered SiOxNy thin films: improving optical efficiency of liquid crystal diffuser elements in multi-focal near-to-eye display architecture

2021

In this work we present reactive sputtered SiOxNy films with a variable refractive index as a convienent solution for contrast improvement of liquid crystal diffuser multi stacks in near-to-eye AR/VR displays. The focus concerns minimization of light reflections between internal structures, in particular ITO, by optimizing internal layers through tailored properties of thin film coatings, as well as subsequent laser patterning of thin film stack. Inorganic thin films have been deposited on glass by physical vapor deposition. Corresponding refractive index, thickness, uniformity and dielectric characteristics and other electro-optical properties have been measured and their impact on the res…