scholarly journals Optical fluxes propagation in the planar transport layer of multilayer coatings

2021 ◽  
Vol 2144 (1) ◽  
pp. 012013
Author(s):  
E V Egorov ◽  
V K Egorov
Keyword(s):  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Multilayer Coating ◽  
Transport Layer ◽  
Multilayer Coatings ◽  
Resonance Mechanism ◽  
Layer Width ◽  
Efficiency Comparison ◽  
Resonance Propagation ◽  
Waveguide Resonance

Abstract The article is concerned with peculiarities study of the quasimonochromatic optical fluxes propagation through thin planar transparent layer of multilayer coating. There is shown that these fluxes can be transported by the layer in process of its multiple consequtive total internal reflection or by the waveguide-resonance propagation manner depending on correlation between the layer width and the radiation coherence length half of transported fluxes. Efficiency comparison of these radiation transportation mechanisms showed that the waveguide-resonance propagation approach is more adequate for results description of the optical waveguides functioning. It allowed to conclude that optical waveguides (fibers) function in frame of the waveguide-resonance paradigm and the waveguide-resonance mechanism is responsible for the light fluxes transportation on great distances.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

Nanowear of Multilayer [(TiCx/Ti/C)÷a-C]n Coatings

2018 ◽  
Vol 279 ◽  
pp. 153-159 ◽  
Author(s):  
Anna P. Rubshtein ◽  
Alexander B. Vladimirov ◽  
Sergey A. Plotnikov
Keyword(s):  
Wear Rate ◽  
Tool Steel ◽  
Elasticity Modulus ◽  
Multilayer Coating ◽  
Wear Test ◽  
Constant Load ◽  
Multilayer Coatings ◽  
Diamond Indenter ◽  
Low Wear

Hard multilayer coatings are technologically promising materials for reducing wear of tribological parts. Multilayer coatings with a systematic alternation of the pair [(TiCx/Ti/C)÷(a-C)] were deposited on stainless and tool steel by the PVD technique. Hardness (H), elasticity modulus (E) and critical cracking load (Pcr) were determined by the nanoindentation method. Nanofrictional wear test was conducted under multipass sliding of a diamond indenter (Ø 50 nm) under constant load. The specific coefficient of nanofrictional wear of [(TiCx/Ti/C)÷(a-C)]nwith different composition of titanium-containing layers was determined. The nanofrictional wear rate of [(TiCx/Ti/C)÷a-C]ndepends on the elastic and plastic characteristics of multilayer coating as a whole. Coatings having H3/E2> 0.12 and Pcr> 58 mN demonstrate low wear rate.

Influence of the nanostructure of the functional layers of a multilayer coating on the wear of a carbide tool

2021 ◽  
pp. 332-336
Author(s):  
A.A. Vereshchaka ◽  
V.P. Tabakov
Keyword(s):  
Fracture Resistance ◽  
Crack Formation ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
Carbide Tool ◽  
Scratch Testing ◽  
Nanolayer Thickness

The results of studies of the effect of nanolayer thickness on the wear of carbide tools are presented. The effect of nanolayer thicknesses on microhardness and fracture resistance of a multilayer coating during scratch testing is shown. The role of nanostructure in the processes of crack formation in multilayer coatings during cutting is revealed.

Application of PVD Coatings for Improvement of Die Performance in Copper Semi-Solid Processing

2006 ◽  
Vol 116-117 ◽  
pp. 84-87 ◽  
Author(s):  
Sang Yong Lee ◽  
Sang Yul Lee
Keyword(s):  
High Temperature ◽  
Protective Coatings ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
H13 Steel ◽  
Crn Coating ◽  
Aisi H13 ◽  
Improved Performance ◽  
Semi Solid ◽  
Superlattice Period

TiAlN/CrN multilayer coatings with an superlattice period of 6.1nm was applied to a proto-type high temperature segment mold for Cu semi-solid processing so that it was investigated the possibilities of TiAlN/CrN multilayer coating as a candidate protective coatings to extend the lifetime of high temperature molds and dies. Much improved performance was obtained from the TiAlN/CrN coated molds, although different behaviors were observed depending upon the type of substrate mold materials. . Improvement of mold performance was observed by TiAlN/CrN coating on AISI H13 steel, but TZM alloy with TiAlN/CrN coating was found to be the best candidate as a mold for high temperature Cu semi-solid processing.

scholarly journals COMPARATIVE CHARACTERISTICS OF COATINGS WITH SiO AND GeO ON LEUCOSAPPHIRE

2021 ◽  
Vol 26 (2(78)) ◽  
pp. 14-21
Author(s):  
V.F. Zinchenko ◽  
I. R. Magunov ◽  
O. V. Mozkova ◽  
B. A. Gorshtein ◽  
V. P. Sobol’ ◽  
...  
Keyword(s):  
Solid Surface ◽  
Multilayer Coating ◽  
Contact Angles ◽  
Qualitative Assessment ◽  
Condensed State ◽  
Multilayer Coatings ◽  
Gaseous State ◽  
Film Forming ◽  
Spectral Ranges ◽  
First Moment

The reasons for the sharp difference in the adhesion of multilayer coatings containing SiO or GeO together with Ge on a leucosapphire (Al2O3) plate have been established. It should be mentioned that Silicon(II) and Germanium(II) oxides are quite stable in the gaseous state and, contrary, are metastable in condensed state; at high temperature they disproportionate into ultra-dispersed composites of amorphous nature. A comparison is made of the surface properties of ultramicroscopic droplets formed on solid surfaces – a substrate or the previous layer – upon condensation of SiO, GeO, or Ge vapors on leucosapphire. A qualitative assessment of the ratio of the corresponding contact angles of wetting by the indicated melts, formed at the first moment of contact, has been carried out. In assessing the surface tension of SiO and GeO melts (or Si – SiO2 and Ge – GeO2 composites), we proceeded from the corresponding values for SiO2 and GeO2, which are 296 and 248 mJ/m2 near the crystallization temperatures. On this basis, it was established that the smallest value of the contact angle, and hence the best wetting, is observed for the GeO melt (somewhat less for the SiO melt) on the solid surface of Al2O3 or Ge; the solid surface of SiO or GeO (especially, the first of them) with molten germanium should be much weaker wetted. Hence, it follows that thin-film multilayer coatings obtained from Ge and GeO on a leucosapphire substrate should have a significantly higher climatic resistance due to higher adhesion compared to multilayer coatings from SiO and Ge. Indeed, a multilayer coating containing SiO on a leucosapphire substrate with a large surface can withstand storage in air for no more than 2–3 months and begins to peel off; at the same time, the GeO coating remains intact after 4 years of storage. Thus, the GeO film-forming material is a promising one for use in multilayer coatings such as cut-off filters in interference optics of the near and mid-IR spectral ranges.

scholarly journals Anomalous Heat Transport in Nanolaminate Metal/Oxide Multilayer Coatings: Plasmon and Phonon Excitations

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 260
Author(s):  
Anatoly Kovalev ◽  
Dmitry Wainstein ◽  
Vladimir Vakhrushev ◽  
Raul Gago ◽  
Jose Luis Endrino
Keyword(s):  
Metal Oxide ◽  
Electronic Structures ◽  
Thermal Conduction ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
Oxide Interfaces ◽  
Multilayer Design ◽  
Different Types ◽  
Plasmon Polariton ◽  
Anomalous Heat

In this work, the anomalous reduction in the thermal conduction observed for nanolaminate metal-dielectric multilayers has been extended to the case of oxides. For this purpose, Ag/Al2O3 coatings were produced with different layer thicknesses (from 1 to 5 nm for Ag and 8 to 40 nm for Al2O3) and numbers of stacks. It was found that the thermal conduction is significantly lower in such metal–oxide nanolaminates compared to the bulk oxide. Such anomalous behaviour is explained by the influence of plasmon and phonon propagation confinement in nanolayers and at the interfaces. To this end, the characteristics of the different types of acoustic and optical phonon waves propagating in the multilayer coating have been studied. In particular, the electronic structures of the different layers and their influences on the plasmon resonance are investigated as a function of the multilayer design. The plasmon-polariton mechanism of energy transfer through oxide–metal and metal–oxide interfaces is discussed.

Study of a hardened multilayer coating obtained by the cold gas-dynamic spraying with laser intensification

2020 ◽  
Vol 86 (7) ◽  
pp. 33-38
Author(s):  
A. I. Gorunov
Keyword(s):  
Multilayer Coating ◽  
Hardened Layer ◽  
Cold Gas Dynamic Spraying ◽  
Carbide Powder ◽  
Multilayer Coatings ◽  
Powder Materials ◽  
Layer By Layer ◽  
Gas Dynamic ◽  
Powder Particles ◽  
Cold Gas

When reconstructing products obtained using additive technologies based on layer-by-layer melting of metal powder by concentrated energy flows, it is advisable to use methods that minimize melting of the initial powder and reduce structural heterogeneity of the material. Cold gas-dynamic spraying with laser-induced intensification of the process (CGDSL) is one of them. The multilayer coatings obtained by the CGDSL method have a homogeneous metal structure though a significant surface roughness attributed to the particle size of the original powder is observed. The goal of the study is to develop a new method of post-processing of multilayer coatings obtained by CGDSL which can provide a hardened layer on their surface. A hardened layer is formed through introduction of boron carbide powder particles into the laser-molten region formed on the surface of the coating based on 316L stainless steel. An acoustic wave triggered by a «microexplosion» induced by a laser pulse above the surface pushes carbide particles in different directions. Some of them are embedded into the melt pool on the surface of the coating. Thus, the laser microdetonation cartooning of the surface of the CGDSL coating is implemeted. Study of the hardened layer revealed a high content of B, C, Cr, Fe, and Ni. Moreover, it is shown that solid carbides of rhombic form are formed in the hardened layer. Chemical and elemental analyzes showed that diamond-shaped carbides — carbides of the type (Fe, Cr)xBy — contain a high concentration of Cr, Fe and a relatively small percentage of C. Most likely formation of diamond-shaped carbides occurs due to interaction of chromium which is a part of the initial hardened coating with boron that released from the surface of BC particles under laser impact. The developed method provides hardening of the surface layer of the coating previously obtained by CGDSL by embedding the BC powder particles into the surface. The technology of hardening CGDSL coatings can be implemented using other powder materials.

Bioactive Glass-Biopolymer Multilayer Coatings Fabricated by Electrophoretic Deposition Combined with Layer-by-Layer Assembly

2015 ◽  
Vol 654 ◽  
pp. 170-175 ◽  
Author(s):  
Qiang Chen ◽  
Sandra Cabanas-Polo ◽  
Ya Ping Ding ◽  
Aldo Roberto Boccaccini
Keyword(s):  
Bioactive Glass ◽  
Electrophoretic Deposition ◽  
Multilayer Coating ◽  
Multilayer Coatings ◽  
Layer By Layer ◽  
Water Contact ◽  
Characterization Methods ◽  
Angle Measurements ◽  
Contact Angle Measurements

45S5 bioactive glass (BG) based multilayer coatings on stainless steel were produced by a combination of electrophoretic deposition (EPD) and layer-by-layer (LbL) deposition. The properties of the multilayer coating were tested with different characterization methods including SEM, FTIR, XRD, laser profilometer and water contact angle measurements. Degradation and in-vitro bioactivity behaviors were tested in simulated body fluid (SBF) over different time periods. The decomposition of the coating was inhibited and the hydroxyapatite (HA) formation after short immersion period (0.5d) was confirmed. At the same time, levofloxacin, used as a model antibiotic, was incorporated into the multilayer structure for antibacterial purpose.

Novel Multilayer Coatings on Polyethylene for Acetabular Devices

2006 ◽  
Vol 514-516 ◽  
pp. 868-871
Author(s):  
Veronica Santos ◽  
João P. Borges ◽  
Cláudia M.S. Ranito ◽  
Eduardo Pires ◽  
Hugo F. Araújo ◽  
...  
Keyword(s):  
Acetabular Component ◽  
Multilayer Coating ◽  
Rf Magnetron Sputtering ◽  
Clinical Work ◽  
Multilayer Coatings ◽  
Titanium Coating ◽  
Acetabular Cup ◽  
Artificial Hip ◽  
Metallic Shell ◽  
Argon Ion Bombardment

Total hip replacement is a common practice in every day clinical work. Artificial hip implants consist of a femoral component and an acetabular component. Nowadays the acetabular component is composed of a polymeric cup and a metallic shell. This study focuses the development of an innovative acetabular component substituting the metallic shell by a multilayer coating on the acetabular cup. A titanium coating was deposited onto ultra-high molecular weight polyethylene (UHMWPE) samples by physical vapour deposition (PVD), having an in situ pretreatment with argon ion bombardment in order to optimize the adhesive strength by surface modification, followed by the deposition of a thin film of hydroxyapatite (HA) using rf magnetron sputtering technique, at room temperature. Results obtained seem to indicate that these multilayer coatings can be a viable alternative to the metallic shell, leading to the substitution of a two part for a one part acetabular component.

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